• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-21
Wout Merbis, Max Riegler

Abstract In this paper we perform the Hamiltonian reduction of the action for three- dimensional Einstein gravity with vanishing cosmological constant using the Chern-Simons formulation and Bondi-van der Burg-Metzner-Sachs (BMS) boundary conditions. An equivalent formulation of the boundary action is the geometric action on BMS3 coad- joint orbits, where the orbit representative is identified as the bulk holonomy. We use this reduced action to compute one-loop contributions to the torus partition function of all BMS3 descendants of Minkowski spacetime and cosmological solutions in flat space. We then consider Wilson lines in the ISO(2, 1) Chern-Simons theory with endpoints on the boundary, whose reduction to the boundary theory gives a bilocal operator. We use the expectation values and two-point correlation functions of these bilocal operators to compute quantum contributions to the entanglement entropy of a single interval for BMS3 invariant field theories and BMS3 blocks, respectively. While semi-classically the BMS3 boundary theory has central charges c1 = 0 and c2 = 3/GN, we find that quantum corrections in flat space do not renormalize GN, but rather lead to a non-zero c1.

更新日期：2020-02-23
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-20
D. Baxter, J. I. Collar, P. Coloma, C. E. Dahl, I. Esteban, P. Ferrario, J. J. Gomez-Cadenas, M.C. Gonzalez-Garcia, A. R. L. Kavner, C. M. Lewis, F. Monrabal, J. Munõz Vidal, P. Privitera, K. Ramanathan, J. Renner

Abstract The European Spallation Source (ESS), presently well on its way to completion, will soon provide the most intense neutron beams for multi-disciplinary science. Fortuitously, it will also generate the largest pulsed neutrino flux suitable for the detection of Coherent Elastic Neutrino-Nucleus Scattering (CEνNS), a process recently measured for the first time at ORNL’s Spallation Neutron Source. We describe innovative detector technologies maximally able to profit from the order-of-magnitude increase in neutrino flux provided by the ESS, along with their sensitivity to a rich particle physics phenomenology accessible through high-statistics, precision CEνNS measurements.

更新日期：2020-02-23
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-20
Aqeel Ahmed, Barry M. Dillon, Saereh Najjari

Abstract We consider a strongly interacting twin Higgs (SITH) model where an ultraviolet completion of twin Higgs mechanism is realized by a strongly coupled approximately scale invariant theory. Besides the Standard Model (SM) and twin sectors, the low energy effective theory contains a relatively light scalar called a dilaton — the pseudo Goldstone boson of spontaneously broken scale invariance. The dilaton provides a unique portal between the SM and twin sectors whose phenomenology could provide an important probe of the twin Higgs mechanism. As a concrete example, we consider a holographic twin Higgs model where the role of the dilaton is played by the radion. The phenomenology of this model is fully determined by a few parameters and our analysis concludes that at the HL-LHC (14 TeV) and HE-LHC (27 TeV) with 3000 fb−1 most of the natural parameter space can be probed.

更新日期：2020-02-23
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-20
Arunima Bhattacharya, Maguni Mahakhud, Prakash Mathews, V. Ravindran

Abstract We compute the radiative corrections to the four-point amplitude g+g → A+A in massless Quantum Chromodynamics (QCD) up to order $${\alpha}_s^4$$ in perturbation theory. We used the effective field theory that describes the coupling of pseudo-scalars to gluons and quarks directly, in the large top quark mass limit. Due to the CP odd nature of the pseudo-scalar Higgs boson, the computation involves careful treatment of chiral quantities in dimensional regularisation. The ultraviolet finite results are shown to be consistent with the universal infrared structure of QCD amplitudes. The infrared finite part of these amplitudes constitutes the important component of any next to next to leading order corrections to observables involving pair of pseudo-scalars at the Large Hadron Collider.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-20
Samuel Abreu, Ruth Britto, Claude Duhr, Einan Gardi, James Matthew

Abstract It is well known that Feynman integrals in dimensional regularization often evaluate to functions of hypergeometric type. Inspired by a recent proposal for a coaction on one-loop Feynman integrals in dimensional regularization, we use intersection numbers and twisted homology theory to define a coaction on certain hypergeometric functions. The functions we consider admit an integral representation where both the integrand and the contour of integration are associated with positive geometries. As in dimensionally- regularized Feynman integrals, endpoint singularities are regularized by means of exponents controlled by a small parameter ϵ. We show that the coaction defined on this class of integral is consistent, upon expansion in ϵ, with the well-known coaction on multiple polylogarithms. We illustrate the validity of our construction by explicitly determining the coaction on various types of hypergeometric p+1Fp and Appell functions.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Björn Garbrecht, Philipp Klose, Carlos Tamarit

Abstract For leptogenesis with heavy sterile neutrinos above the electroweak scale, asymmetries produced at early times (in the relativistic regime) are relevant, if they are protected from washout. This can occur for weak washout or when the asymmetry is partly protected by being transferred to spectator fields. We thus study the relevance of relativistic effects for leptogenesis in a minimal seesaw model with two sterile neutrinos in the strongly hierarchical limit. Starting from first principles, we derive a set of momentum-averaged fluid equations to calculate the final B − L asymmetry as a function of the washout strength and for different initial conditions at order one accuracy. For this, we take the leading fluid approximation for the relativistic CP-even and odd rates. Assuming that spectator fields remain in chemical equilibrium, we find that for weak washout, relativistic corrections lead to a sign flip and an enhancement of the asymmetry for a vanishing initial abundance of sterile neutrinos. As an example for the effect of partially equilibrated spectators, we consider bottom-Yukawa and weak-sphaleron interactions in leptogenesis driven by sterile neutrinos with masses ≳ 5 × 1012 GeV. For a vanishing initial abundance of sterile neutrinos, this can give rise to another flip and an absolute enhancement of the final asymmetry in the strong washout regime by up to two orders of magnitude relative to the cases either without spectators or with fully equilibrated ones. These effects are less pronounced for thermal initial conditions for the sterile neutrinos. The CP-violating source in the relativistic regime at early times is important as it is proportional to the product of lepton-number violating and lepton-number conserving rates, and therefore less suppressed than an extrapolation of the nonrelativistic approximations may suggest.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Gabriel Cuomo

Abstract We include vortices in the superfluid EFT for four dimensional CFTs at large global charge. Using the state-operator correspondence, vortices are mapped to charged operators with large spin and we compute their scaling dimensions. Different regimes are identified: phonons, vortex rings, Kelvin waves, and vortex crystals. We also compute correlators with a Noether current insertion in between vortex states. Results for the scaling dimensions of traceless symmetric operators are given in arbitrary spacetime dimensions.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Heng-Yu Chen, Taro Kimura, Norton Lee

Abstract We systematically study the interesting relations between the quantum elliptic Calogero-Moser system (eCM) and its generalization, and their corresponding supersymmetric gauge theories. In particular, we construct the suitable characteristic polynomial for the eCM system by considering certain orbifolded instanton partition function of the corresponding gauge theory. This is equivalent to the introduction of certain co-dimension two defects. We next generalize our construction to the folded instanton partition function obtained through the so-called “gauge origami” construction and precisely obtain the corresponding characteristic polynomial for the doubled version, named the elliptic double Calogero-Moser (edCM) system.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Amin Aboubrahim, Wan-Zhe Feng, Pran Nath

Abstract In extended supersymmetric models with a hidden sector the lightest R-parity odd particle can reside in the hidden sector and act as dark matter. We consider the case when the hidden sector has ultraweak interactions with the visible sector. An interesting phenomenon arises if the LSP of the visible sector is charged in which case it will decay to the hidden sector dark matter. Due to the ultraweak interactions, the LSP of the visible sector will be long-lived decaying outside the detector after leaving a track inside. We investigate this possibility in the framework of a U(1)X-extended MSSM/SUGRA model with a small gauge kinetic mixing and mass mixing between the U(1)X and U(1)Y where U(1)Y is the gauge group of the hypercharge. Specifically we investigate the case when the LSP of MSSM is a stop which decays into the hidden sector dark matter and has a lifetime long enough to traverse the LHC detector without decay. It is shown that such a particle can be detected at the HL-LHC and HE-LHC as an R-hadron which will look like a slow moving muon with a large transverse momentum pT and so can be detected by the track it leaves in the inner tracker and in the muon spectrometer. Further, due to the ultraweak couplings between the hidden sector and the MSSM fields, the dark matter particle has a relic density arising from a combination of the freeze-out and freeze-in mechanisms. It is found that even for the ultraweak or feeble interactions the freeze-out contribution relative to freeze-in contribution to the relic density is substantial to dominant, varying between 30% to 74% for the model points considered. It is subdominant to freeze-in for relatively small stop masses with relatively larger stop annihilation cross-sections and the dominant contribution to the relic density for relatively large stop masses and relatively smaller stop annihilation cross-sections. Our analysis shows that the freeze-out contribution must be included for any realistic analysis even for dark matter particles with ultraweak or feeble interactions with the visible sector. A discovery of a long-lived stop as the lightest particle of the MSSM may point to the nature of dark matter and its production mechanism in the early universe.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-20
Gregor Kälin, Rafael A. Porto

Abstract We recently introduced in [9] a boundary-to-bound dictionary between gravitational scattering data and observables for bound states of non-spinning bodies. In this paper, we elaborate further on this holographic map. We start by deriving the following — remarkably simple — formula relating the periastron advance to the scattering angle: $$\Delta \Phi \left(J,\mathcal{E}\right)=\upchi \left(J,\mathcal{E}\right)+\upchi \left(-J,\mathcal{E}\right)$$, via analytic continuation in angular momentum and binding energy. Using explicit expressions from [9], we confirm its validity to all orders in the Post-Minkowskian (PM) expansion. Furthermore, we reconstruct the radial action for the bound state directly from the knowledge of the scattering angle. The radial action enables us to write compact expressions for dynamical invariants in terms of the deflection angle to all PM orders, which can also be written as a function of the PM-expanded amplitude. As an example, we reproduce our result in [9] for the periastron advance, and compute the radial and azimuthal frequencies and redshift variable to two-loops. Agreement is found in the overlap between PM and Post-Newtonian (PN) schemes. Last but not least, we initiate the study of our dictionary including spin. We demonstrate that the same relation between deflection angle and periastron advance applies for aligned-spin contributions, with J the (canonical) total angular momentum. Explicit checks are performed to display perfect agreement using state-of-the-art PN results in the literature. Using the map between test- and two-body dynamics, we also compute the periastron advance up to quadratic order in spin, to one-loop and to all orders in velocity. We conclude with a discussion on the generalized ‘impetus formula’ for spinning bodies and black holes as ‘elementary particles’. Our findings here and in [9] imply that the deflection angle already encodes vast amount of physical information for bound orbits, encouraging independent derivations using numerical and/or self-force methodologies.

更新日期：2020-02-21
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Wen Chen

Abstract In this paper, the reduction of Feynman integrals in the parametric representation is considered. This method proves to be more efficient than the integration-by-part (IBP) method in the momentum space. Tensor integrals can directly be parametrized without performing tensor reductions. The integrands of parametric integrals are functions of Lorentz scalars, instead of four momenta. The complexity of a calculation is determined by the number of propagators that are present rather than the number of all the linearly independent propagators. Furthermore, the symmetries of Feynman integrals under permutations of indices are transparent in the parametric representation. Since all the indices of the propagators are nonnegative, an algorithm to solve those identities can easily be developed, which can be used for automatic calculations.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Astrid Eichhorn, Johannes Lumma, Antonio D. Pereira, Arslan Sikandar

Abstract Four-dimensional random geometries can be generated by statistical models with rank-4 tensors as random variables. These are dual to discrete building blocks of random geometries. We discover a potential candidate for a continuum limit in such a model by employing background-independent coarse-graining techniques where the tensor size serves as a pre-geometric notion of scale. A fixed point candidate which features two relevant directions is found. The possible relevance of this result in view of universal results for quantum gravity and a potential connection to the asymptotic-safety program is discussed.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Costas G. Papadopoulos, Christopher Wever

Abstract A new approach to compute Feynman Integrals is presented. It relies on an integral representation of a given Feynman Integral in terms of simpler ones. Using this approach, we present, for the first time, results for a certain family of non-planar five-point two-loop Master Integrals with one external off-shell particle, relevant for instance for H + 2 jets production at the LHC, in both Euclidean and physical kinematical regions.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Subham Dutta Chowdhury, Abhijit Gadde, Tushar Gopalka, Indranil Halder, Lavneet Janagal, Shiraz Minwalla

Abstract We study the space of all kinematically allowed four photon and four graviton S-matrices, polynomial in scattering momenta. We demonstrate that this space is the permutation invariant sector of a module over the ring of polynomials of the Mandelstam invariants s, t and u. We construct these modules for every value of the spacetime dimension D, and so explicitly count and parameterize the most general four photon and four graviton S-matrix at any given derivative order. We also explicitly list the local Lagrangians that give rise to these S-matrices. We then conjecture that the Regge growth of S-matrices in all physically acceptable classical theories is bounded by s2 at fixed t. A four parameter subset of the polynomial photon S-matrices constructed above satisfies this Regge criterion. For gravitons, on the other hand, no polynomial addition to the Einstein S-matrix obeys this bound for D ≤ 6. For D ≥ 7 there is a single six derivative polynomial Lagrangian consistent with our conjectured Regge growth bound. Our conjecture thus implies that the Einstein four graviton S-matrix does not admit any physically acceptable polynomial modifications for D ≤ 6. A preliminary analysis also suggests that every finite sum of pole exchange contributions to four graviton scattering also violates our conjectured Regge growth bound, at least when D ≤ 6, even when the exchanged particles have low spin.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Francesco Andreucci, Andrea Cappelli, Lorenzo Maffi

Abstract Compact nonlocal Abelian gauge theory in (2 + 1) dimensions, also known as loop model, is a massless theory with a critical line that is explicitly covariant under duality transformations. It corresponds to the large NF limit of self-dual electrodynamics in mixed three-four dimensions. It also provides a bosonic description for surface excitations of three-dimensional topological insulators. Upon mapping the model to a local gauge theory in (3 + 1) dimensions, we compute the spectrum of electric and magnetic solitonic excitations and the partition function on the three torus $${\mathbbm{T}}_3$$. Analogous results for the S2 × S1 geometry show that the theory is conformal invariant and determine the manifestly self-dual spectrum of conformal fields, corresponding to order-disorder excitations with fractional statistics.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Domenico Fiorenza, Hisham Sati, Urs Schreiber

Abstract In the quest for the mathematical formulation of M-theory, we consider three major open problems: a first-principles construction of the single (abelian) M5-brane Lagrangian density, the origin of the gauge field in heterotic M-theory, and the supersymmetric enhancement of exceptional M-geometry. By combining techniques from homotopy theory and from supergeometry to what we call super-exceptional geometry within super-homotopy theory, we present an elegant joint solution to all three problems. This leads to a unified description of the Nambu-Goto, Perry-Schwarz, and topological Yang-Mills Lagrangians in the topologically nontrivial setting. After explaining how charge quantization of the C-field in Cohomotopy reveals D’Auria-Fré’s “hidden supergroup” of 11d supergravity as the super-exceptional target space, in the sense of Bandos, for M5-brane sigma-models, we prove, in exceptional generalization of the doubly-supersymmetric super-embedding formalism, that a Perry-Schwarz-type Lagrangian for single (abelian) $$\mathcal{N}$$ = (1, 0) M5-branes emerges as the super-exceptional trivialization of the M5-brane cocycle along the super-exceptional embedding of the “half ” M5-brane locus, super-exceptionally compactified on the Hořava-Witten circle fiber. From inspection of the resulting 5d super Yang-Mills Lagrangian we find that the extra fermion field appearing in super-exceptional M-geometry, whose physical interpretation had remained open, is the M-theoretic avatar of the gaugino field.

更新日期：2020-02-20
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Kohei Fujikura, Yuichiro Nakai, Masaki Yamada

Abstract We propose a new radion stabilization mechanism in the Randall-Sundrum spacetime, introducing a bulk SU(NH) gauge field which confines at a TeV scale. It turns out that the radion is stabilized by the balance between a brane tension and a pressure due to the Casimir energy of the strong SU(NH) gauge field. We investigate the phase transition between the Randall-Sundrum (compactified) spacetime and a de-compactified spacetime and determine the parameter regime in which eternal (old) inflation is avoided and the phase transition can be completed. In comparison to the Goldberger-Wise mechanism, the 5D Planck mass can be larger than the AdS curvature and a classical description of the gravity is reliable in our stabilization mechanism. We also discuss the effect of the phase transition in cosmology such as an entropy dilution and a production of gravitational waves.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Dibakar Roychowdhury

Abstract We show nonrelativistic (NR) giant magnon dispersion relations by probing the torsional Newton Cartan (TNC) geometry with (semi)classical nonrelativistic rigidly rotating strings. We construct NR sigma models over R × S2 and consider two specific limiting cases those are of particular interest. Both of these limiting conditions give rise to what we identify as the small momentum limit of the giant magnon dispersion relation in the dual SMT at strong coupling. We further generalize our results in the presence of background NS-NS fluxes. Our analysis reveals that unlike its relativistic counterpart, the NR string theory lacks of single spike solutions.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-19
Daniel Robbins, Thomas Vandermeulen

Abstract We extend the modular orbits method of constructing a two-dimensional orbifold conformal field theory to higher genus Riemann surfaces. We find that partition functions on surfaces of arbitrary genus can be constructed by a straightforward generalization of the rules that one would apply to the torus. We demonstrate how one can use these higher genus objects to compute correlation functions and OPE coefficients in the underlying theory. In the case of orbifolds of free bosonic theories by subgroups of continuous symmetries, we can give the explicit results of our procedure for symmetric and asymmetric orbifolds by cyclic groups.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Yu Muramatsu, Yoshihiro Shigekami

Abstract In the standard model (SM), the Cabibbo-Kobayashi-Maskawa (CKM) matrix is the only origin of flavor violations (FVs). On the other hand, in general, there are a lot of sources of the FVs in a physics beyond the SM, through the diagonalizing matrices which make Yukawa matrices diagonal. Although most of the diagonalizing matrices are unknown ones, grand unified theories (GUTs) can fix these matrices. In particular, if we consider a GUT model based on the SO(10) group, these diagonalizing matrices are strongly related to each other because of the matter unification. However, this unification causes the problem on the realization of measured SM fermion masses and mixing angles. Up to now, many people showed that supersymmetric (SUSY) threshold corrections can solve this problem, especially unfavorable fermion mass relations. In this paper, we show that how these SUSY threshold corrections affect unknown diagonalizing matrices. Since these contributions are also related to the FVs induced by SUSY particles, we can estimate the maximal effect to the diagonalizing matrices. We found that the (1, 3) and (3, 1) elements of diagonalizing matrices for quarks can be as large as the corresponding mixing angle of the CKM matrix. Moreover, we found that the higher SUSY scale can predict the larger mixing angles, although strong cancellation between the Higgs mass parameters is needed to realize the electroweak symmetry breaking.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Claude Duhr, Lorenzo Tancredi

Abstract We present algorithms to work with iterated Eisenstein integrals that have recently appeared in the computation of multi-loop Feynman integrals. These algorithms allow one to analytically continue these integrals to all regions of the parameter space, and to obtain fast converging series representations in each region. We illustrate our approach on the examples of hypergeometric functions that evaluate to iterated Eisenstein integrals as well as the well-known sunrise graph.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Federico Carta, Simone Giacomelli, Hirotaka Hayashi, Raffaele Savelli

Abstract We provide a precise geometric picture that demystifies the phenomenon of supersymmetry enhancement along certain RG flows of four-dimensional field theories, recently discovered by Maruyoshi and Song. It applies to theories of arbitrary rank and it is based on a hyperkähler-structure restoration on the moduli space of solutions of (twisted) Hitchin systems, which underly the class-$$\mathcal{S}$$ construction we use as an engineering tool. Along the way, we formulate a necessary algebraic condition for supersymmetry enhancement, and, when enhancement occurs, we are able to derive the Seiberg-Witten geometry and all conformal dimensions of Coulomb-branch operators for the infrared theory, without using a-maximization.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14

In figure 11 of the original paper.

更新日期：2020-02-19
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Dongmin Gang, Masahito Yamazaki

Abstract We study a perturbative expansion of the squashed 3-sphere $$\left({s}_b^3\right)$$ partition function of 3d $$\mathcal{N}$$ = 2 gauge theories around the squashing parameter b = 1. Our proposal gives the coefficients of the perturbative expansion as a finite sum over the saddle points of the supersymmetric-localization integral in the limit b → 0 (the so-called Bethe vacua), and the contribution from each Bethe vacua can be systematically computed using saddle-point methods. Our expansion provides an efficient and practical method for computing basic CFT data (F, CT, CJJ and higher-point correlation functions of the stress-energy tensor) of the IR superconformal field theory without performing the localization integrals.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-18
Xin Li, Yu Tian, Hongbao Zhang

Abstract Within the simplest holographic superfluid model and without any ingredient put by hand, it is shown that vortices can be generated when the angular velocity of rotating superfluids exceeds certain critical values, which can be precisely determined by linear perturbation analyses (quasi-normal modes of the bulk AdS black brane). These vortices appear at the edge of the superfluid system first, and then automatically move into the bulk of the system, where they are eventually stabilized into certain vortex lattices. For the case of 18 vortices generated, we find (at least) five different patterns of the final lattices formed due to different initial perturbations, which can be compared to the known result for such lattices in weakly coupled Bose-Einstein condensates from free energy analyses.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Nicolas Kovensky, Andreas Schmitt

Abstract We study the phase structure of the Witten-Sakai-Sugimoto model in the plane of temperature and baryon chemical potential, including the effect of a nonzero current quark mass. Our study is performed in the decompactified limit of the model, which, at least regarding the chiral phase transition, appears to be closer to real-world QCD than the original version. Following earlier studies, we account for the quark mass in an effective way based on an open Wilson line operator whose expectation value is identified with the chiral condensate. We find that the quark mass stabilizes a configuration with string sources and point out that this phase plays an important role in the phase diagram. Furthermore, we show that the quark mass breaks up the first-order chiral phase transition curve and introduces critical points to the phase diagram. Similarities of the phase structure to other holographic approaches and to lattice simulations of “heavy QCD” are found and discussed. By making holographic QCD more realistic, our results open the door to a better understanding of real-world strongly coupled hot and dense matter.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Charlotte Sleight, Massimo Taronna

Abstract We develop a Mellin space approach to boundary correlation functions in anti-de Sitter (AdS) and de Sitter (dS) spaces. Using the Mellin-Barnes representation of correlators in Fourier space, we show that the analytic continuation between AdSd+1 and dSd+1 is encoded in a collection of simple relative phases. This allows us to determine the late-time tree-level three-point correlators of spinning fields in dSd+1 from known results for Witten diagrams in AdSd+1 by multiplication with a simple trigonometric factor. At four point level, we show that Conformal symmetry fixes exchange four-point functions both in AdSd+1 and dSd+1 in terms of the dual Conformal Partial Wave (which in Fourier space is a product of boundary three-point correlators) up to a factor which is determined by the boundary conditions. In this work we focus on late-time four-point correlators with external scalars and an exchanged field of integer spin-ℓ. The Mellin-Barnes representation makes manifest the analytic structure of boundary correlation functions, providing an analytic expression for the exchange four-point function which is valid for general d and generic scaling dimensions, in particular massive, light and (partially-)massless fields. It moreover naturally identifies boundary correlation functions for generic fields with multi-variable Meijer-G functions. When d = 3 we reproduce existing explicit results available in the literature for external conformally coupled and massless scalars. From these results, assuming the weak breaking of the de Sitter isometries, we extract the corresponding correction to the inflationary three-point function of general external scalars induced by a general spin- ℓ field at leading order in slow roll. These results provide a step towards a more systematic understanding of de Sitter observables at tree level and beyond using Mellin space methods.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Yu Gao, Mingjie Jin, Kechen Wang

Abstract The Higgs boson can mix with a singlet scalar that dynamically generates the Majorana mass of the right-handed neutrino NR. We show that even a tiny mixing between the Higgs boson and a ‘decoupled’ singlet scalar allows for Higgs-mediated pair production of NR without significant mixings between the active neutrinos and NR, and thus testable at colliders via a characteristic signal of two same-sign same-flavor lepton pairs, plus missing energy. We demonstrate that this search channel is mostly background- free in pp-collision and can be a highly sensitive probe of the Higgs-singlet mixing at the current and future pp colliders. Such channel provides a clean signal to discover the singlet scalar and explore the origin of neutrino masses.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Jacob L. Bourjaily, Matthias Volk, Matt von Hippel

Abstract We reproduce the two-loop seven-point remainder function in planar, maximally supersymmetric Yang-Mills theory by direct integration of conformally-regulated chiral integrands. The remainder function is obtained as part of the two-loop logarithm of the MHV amplitude, the regularized form of which we compute directly in this scheme. We compare the scheme-dependent anomalous dimensions and related quantities in the conformal regulator with those found for the Higgs regulator.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Tatsuo Kobayashi, Yusuke Shimizu, Kenta Takagi, Morimitsu Tanimoto, Takuya H. Tatsuishi

Abstract We study a flavor model with A4 symmetry which originates from S4 modular group. In S4 symmetry, Z2 subgroup can be anomalous, and then S4 can be violated to A4. Starting with a S4 symmetric Lagrangian at the tree level, the Lagrangian at the quantum level has only A4 symmetry when Z2 in S4 is anomalous. We obtain modular forms of two singlets and a triplet representations of A4 by decomposing S4 modular forms into A4 representations. We propose a new A4 flavor model of leptons by using those A4 modular forms. We succeed in constructing a viable neutrino mass matrix through the Weinberg operator for both normal hierarchy (NH) and inverted hierarchy (IH) of neutrino masses. Our predictions of the CP violating Dirac phase δCP and the mixing sin2θ23 depend on the sum of neutrino masses for NH.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Jacques Distler, Mario Martone, Andrew Neitzke

Abstract The F-theory realization of the rank-1 Minahan Nemeschansky (MN) E6, E7 and E8 theories leads to a description of the BPS states on the Coulomb branch in terms of Type IIB (p, q)-string networks. Subject to a simple ansatz for the types of networks which can occur, we study the representations of the flavor symmetry group which occur in the BPS spectrum. The results we find for the E6 and E7 theories are in perfect agreement with previous calculations by other methods (in particular, we find that arbitrarily large representations occur), but our scheme is easier to implement and more computationally efficient. The string network picture also gives a possible explanation of the experimental observation that in rank-1 MN theories, BPS states whose charge is n times a primitive charge occur with BPS index divisible by (−1)n+1n.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Enrico Herrmann, Julio Parra-Martinez

Abstract We describe in detail how a d log representation of Feynman integrals leads to simple differential equations. We derive these differential equations directly in loop momentum or embedding space making use of a localization trick and generalized unitarity. For the examples we study, the alphabet of the differential equation is related to special points in kinematic space, described by certain cut equations which encode the geometry of the Feynman integral. At one loop, we reproduce the motivic formulae described by Goncharov [1] that reappeared in the context of Feynman integrals in [2–4]. The d log representation allows us to generalize the differential equations to higher loops and motivates the study of certain mixed-dimension integrals.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-17
Yunfeng Jiang

Abstract We study the expectation value of the $$\mathrm{T}\overline{\mathrm{T}}$$ operator in maximally symmetric spacetimes. We define an diffeomorphism invariant biscalar whose coinciding limit gives the expectation value of the $$\mathrm{T}\overline{\mathrm{T}}$$ operator. We show that this biscalar is a constant in flat spacetime, which reproduces Zamolodchikov’s result in 2004. For spacetimes with non-zero curvature, we show that this is no longer true and the expectation value of the $$\mathrm{T}\overline{\mathrm{T}}$$ operator depends on both the one- and two-point functions of the stress-energy tensor.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
S. Kürkçüoğlu, G. Ünal, İ. Yurduşen

Abstract Continuum models for time-reversal (TR) invariant topological insulators (Tis) in d ≥ 3 dimensions are provided by harmonic oscillators coupled to certain SO(d) gauge fields. These models are equivalent to the presence of spin-orbit (SO) interaction in the oscillator Hamiltonians at a critical coupling strength (equivalent to the harmonic oscillator frequency) and leads to flat Landau Level (LL) spectra and therefore to infinite degeneracy of either the positive or the negative helicity states depending on the sign of the SO coupling. Generalizing the results of [1] to d ≥ 4, we construct vector operators commuting with these Hamiltonians and show that SO(d, 2) emerges as the non-compact extended dynamical symmetry. Focusing on the model in four dimensions, we demonstrate that the infinite degeneracy of the flat spectra can be fully explained in terms of the discrete unitary representations of SO(4,2), i.e. the doubletons. The degeneracy in the opposite helicity branch is finite, but can still be explained exploiting the complex conjugate doubleton representations. Subsequently, the analysis is generalized to d-dimensions, distinguishing the cases of odd and even d. We also determine the spectrum generating algebra in these models and briefly comment on the algebraic organization of the LL states w.r.t. an underlying “deformed” AdS geometry as well as on the organization of the surface states under open boundary conditions in view of our results.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
Song He, Hongfei Shu

Abstract In this paper, we regard the $$T\overline{T}/J\overline{T}$$-deformed CFTs as perturbation theories and calculate the first order correction of the correlation functions due to the $$T\overline{T}/J\overline{T}$$­deformation. As applications, we study the Rényi entanglement entropy of excited state in the $$T\overline{T}/J\overline{T}$$-deformed two-dimensional CFTs. We find, up to the first order perturbation of the deformation, the Rényi entanglement entropy of locally excited states will acquire a non­trivial time dependence. The excess of the Rényi entanglement entropy of locally excited state is changed up to order O(c). Furthermore, the out of time ordered correlation function is investigated to confirm that the $$T\overline{T}/J\overline{T}$$-deformations do not change the maximal chaotic behavior of holographic CFTs up to the first order of the deformations.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
Darius A. Faroughy, Jernej F. Kamenik, Nejc Košnik, Aleks Smolkovič

Abstract We analyze the prospects of probing the C P -odd $$i\tilde{\kappa}\overline{t}\gamma$$5th interaction at the LHC and its projected upgrades, the high-luminosity and high-energy LHC, directly using associated on-shell Higgs boson and top quark or top quark pair production. To this end we first construct a C P -odd observable based on top quark polarization in Wb → th scattering with optimal linear sensitivity to $$\tilde{\kappa}$$. For the corresponding hadronic process pp → thj we present a method of extracting the phase-space dependent weight function that allows to retain close to optimal sensitivity to $$\tilde{\kappa}$$. We project future sensitivity to the signal in pp → t(→ ℓ𝜈b)h(→ b$$\overline{b}$$)j. We also propose novel C P -odd observables for top quark pair production in association with the Higgs, pp → t$$\overline{t}$$h, with semileptonically decaying tops and h → b$$\overline{b}$$, that rely solely on measuring the momenta of leptons and b-jets from the decaying tops without having to distinguish the charge of the b-jets. Among the many possibilities we single out an observable that can potentially probe $$\tilde{\kappa}$$ ∼ 0.1 at the high-energy LHC with 2𝜎 confidence.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
Dimitrios Katsinis, Georgios Pastras

Abstract We study the entanglement entropy and the mutual information in coupled harmonic systems at finite temperature. Interestingly, we find that the mutual information does not vanish at infinite temperature, but it rather reaches a specific finite value, which can be attributed to classical correlations solely. We further obtain high and low temperature expansions for both quantities. Then, we extend the analysis performed in the seminal paper by Srednicki [1] for free real scalar field theories in Minkowski space-time in 3 + 1 dimensions at a thermal state. We find that the mutual information obeys an area law, similar to that obeyed by the entanglement entropy at vanishing temperature. The coefficient of this area law does not vanish at infinite temperature. Then, we calculate this coefficient perturbatively in a 1/μ expansion, where μ is the mass of the scalar field. Finally, we study the high and low temperature behaviour of the area law term.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
Andreas Banlaki, Abhishek Chowdhury, Abhiram Kidambi, Maria Schimpf

Abstract We provide further evidence that CY3 manifolds are involved in an intricate way in Mathieu moonshine, i.e., their Gromov-Witten invariants are related to the expansion coefficients of the twined/twisted-twined elliptic genera of K3. We use the string duality between CHL orbifolds of heterotic string theory on K3 × T2 and type IIA string theory on CY3 manifolds to explicitly show this connection. We then work out two concrete examples where we exactly match the expansion coefficients on both sides of the duality.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
Marieke Postma, Jorinde van de Vis

Abstract In electroweak baryogenesis the baryon asymmetry of the universe is created during the electroweak phase transition. The quantum transport equations governing the dynamics of the plasma particles can be derived in the vev-insertion approximation, which treats the vev-dependent part of the particle masses as a perturbation. We calculate the next-to-leading order (NLO) contribution to the CP-violating source term and CP-conserving relaxation rate, corresponding to Feynman diagrams for the self-energies with four mass insertions. We consider both a pair of Weyl fermions and a pair of complex scalars, that scatter off the bubble wall. We find: (i) The NLO correction becomes large for $$\mathcal{O}$$(1) couplings. If only the Standard Model (SM) Higgs obtains a vev during the phase transition, this implies the vev-insertion approximation breaks down for top quarks. (ii) The resonant enhancement of the source term and relaxation rate, that exists at leading order in the limit of degenerate thermal masses for the fermions/scalars, persists at NLO.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-14
Walter D. Goldberger, Jingping Li

Abstract We extend Shen’s recent formulation (arXiv:1806.07388) of the classical double copy, based on explicit color-kinematic duality, to the case of finite-size sources with non-zero spin. For the case of spinning Yang-Mills sources, the most general consistent double copy consists of gravitating objects which carry pairs of spin degrees of freedom. We find that the couplings of such objects to background fields match those of a classical (i.e. heavy) closed bosonic string, suggesting a string theory interpretation of sources related by color-kinematics duality. As a special case, we identify a limit, corresponding to unoriented strings, in which the 2-form Kalb-Ramond axion field decouples from the gravitational side of the double copy. Finally, we apply the classical double copy to extended objects, described by the addition of finite-size operators to the worldline effective theory. We find that consistency of the color-to-kinematics map requires that the Wilson coefficients of tidal operators obey certain relations, indicating that the extended gravitating objects generated by the double copy of Yang-Mills are not completely generic.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
M. Grazzini, S. Kallweit, J.M. Lindert, S. Pozzorini, M. Wiesemann

Abstract We present the first combination of NNLO QCD and NLO EW corrections for vector-boson pair production at the LHC. We consider all final states with two, three and four charged leptons, including resonant and non-resonant diagrams, spin correlations and off-shell effects. Detailed predictions are discussed for three representative channels corresponding to W+W−, W±Z and Z Z production. Both QCD and EW corrections are very significant, and the details of their combination can play a crucial role to achieve the level of precision demanded by experimental analyses. In this context we point out nontrivial issues that arise at large transverse momenta, where the EW corrections are strongly enhanced by Sudakov logarithms and the QCD corrections can feature so-called giant K -factors. Our calculations have been carried out in the Matrix+OpenLoops framework and can be extended to the production of an arbitrary colour singlet in hadronic collisions, provided that the required two-loop QCD amplitudes are available. Combined NNLO QCD and NLO EW predictions for the full set of massive diboson processes will be made publicly available in the next release of Matrix and will be instrumental in advancing precision diboson studies and new-physics searches at the LHC and future hadron colliders.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13

Abstract In this paper, a modified teleparallel gravity action containing a coupling be- tween a scalar field potential and magnetism, in anisotropic and homogeneous backgrounds, is investigated through Noether symmetry approach. The focus of this work is to describe late-time-accelerated expansion. Since finding analytical solutions carrying all conserved currents emerged by Noether symmetry approach, is very difficult, hence regularly in the literature, the authors split the total symmetry into sub-symmetries and then select, usually, some of them to be carried by the solutions. This manner limits the forms of unknown functions obtained. However, in ref. [67], B.N.S. approach was proposed in order to solve such problems but its main motivation was carrying more conserved currents by solutions. In this paper, by eliminating the aforementioned limitation as much as possible, a trick leading to some graceful forms of unknown functions is suggested. Through this fruitful approach, the solutions may carry more conserved currents than usual ways and maybe new forms of symmetries. I named this new approach to be CSSS-trick (Combination of Sub-symmetries through Special Selections). With this approach, it is demonstrated that the unified dark matter potential is deduced by the gauge fields. Utilizing the B-function method, a detailed data analysis of results obtained yielding perfect agreements with recent observational data are performed. And finally, the Wheeler-De Witt (WDW) equation is discussed to demonstrate recov- ering the Hartle criterion due to the oscillating feature of the wave function of the universe.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Sorna Prava Barik, Rashmi R. Nayak, Kamal L. Panigrahi

Abstract We discuss finite-size corrections to the spiky strings in AdS space which is dual to the long 𝒩 = 4 SYM operators of the form Tr($${\varDelta}_{+}^{J_1}{\phi}_1{\varDelta}_{+}^{J_2}{\phi}_2\dots {\varDelta}_{+}^{J_n}{\phi}_n$$). We express the finite-size dispersion relation in terms of Lambert W-function. We further establish the finite-size scaling relation between energy and angular momentum of the spiky string in presence of mixed fluxes in terms of W-function. We comment on the solution in pure NS-NS background as well.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Tudor Dimofte, Niklas Garner, Michael Geracie, Justin Hilburn

Abstract We study half-BPS line operators in 3d $$\mathcal{N}$$ = 4 gauge theories, focusing in particular on the algebras of local operators at their junctions. It is known that there are two basic types of such line operators, distinguished by the SUSY subalgebras that they preserve; the two types can roughly be called “Wilson lines” and “vortex lines,” and are exchanged under 3d mirror symmetry. We describe a large class of vortex lines that can be characterized by basic algebraic data, and propose a mathematical scheme to compute the algebras of local operators at their junctions — including monopole operators — in terms of this data. The computation generalizes mathematical and physical definitions/analyses of the bulk Coulomb-branch chiral ring. We fully classify the junctions of half-BPS Wilson lines and of half-BPS vortex lines in abelian gauge theories with sufficient matter. We also test our computational scheme in a non-abelian quiver gauge theory, using a 3d-mirror-map of line operators from work of Assel and Gomis.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12

Abstract The multiplicity dependence of electron production from heavy-flavour hadron decays as a function of transverse momentum was measured in p-Pb collisions at $$\sqrt{s_{\mathrm{NN}}}$$ = 5.02 TeV using the ALICE detector at the LHC. The measurement was performed in the centre-of-mass rapidity interval −1.07 < ycms< 0.14 and transverse momentum interval 2 < pT< 16 GeV/c. The multiplicity dependence of the production of electrons from heavy-flavour hadron decays was studied by comparing the pT spectra measured for different multiplicity classes with those measured in pp collisions (QpPb) and in peripheral p-Pb collisions (Qcp). The QpPb results obtained are consistent with unity within uncertainties in the measured pT interval and event classes. This indicates that heavy-flavour decay electron production is consistent with binary scaling and independent of the geometry of the collision system. Additionally, the results suggest that cold nuclear matter effects are negligible within uncertainties, in the production of heavy-flavour decay electrons at midrapidity in p-Pb collisions.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Dominik Bendle, Janko Böhm, Wolfram Decker, Alessandro Georgoudis, Franz-Josef Pfreundt, Mirko Rahn, Pascal Wasser, Yang Zhang

Abstract We introduce an algebro-geometrically motived integration-by-parts (IBP) re- duction method for multi-loop and multi-scale Feynman integrals, using a framework for massively parallel computations in computer algebra. This framework combines the com- puter algebra system Singular with the workflow management system GPI-Space, which are being developed at the TU Kaiserslautern and the Fraunhofer Institute for Industrial Mathematics (ITWM), respectively. In our approach, the IBP relations are first trimmed by modern tools from computational algebraic geometry and then solved by sparse linear algebra and our new interpolation method. Modelled in terms of Petri nets, these steps are efficiently automatized and automatically parallelized by GPI-Space. We demonstrate the potential of our method at the nontrivial example of reducing two-loop five-point non- planar double-pentagon integrals. We also use GPI-Space to convert the basis of IBP reductions, and discuss the possible simplification of master-integral coefficients in a uni- formly transcendental basis.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Dario Benedetti, Razvan Gurau, Sabine Harribey, Kenta Suzuki

Abstract We compute the OPE coefficients of the bosonic tensor model of [1] for three point functions with two fields and a bilinear with zero and non-zero spin. We find that all the OPE coefficients are real in the case of an imaginary tetrahedral coupling constant, while one of them is not real in the case of a real coupling. We also discuss the operator spectrum of the free theory based on the character decomposition of the partition function.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Yusuke Kimura

Abstract In this study, we introduce a new class of rational elliptic 3-folds, which we refer to as “1/2 Calabi-Yau 3-folds”. We construct elliptically fibered Calabi-Yau 3-folds by utilizing these rational elliptic 3-folds. The construction yields a novel approach to build elliptically fibered Calabi-Yau 3-folds of various Mordell-Weil ranks. Our construction of Calabi-Yau 3-folds can be considered as a three-dimensional generalization of the operation of gluing pairs of 1/2 K3 surfaces to yield elliptic K3 surfaces. From one to seven U(1)s form in six-dimensional N = 1 F-theory on the constructed Calabi-Yau 3-folds. Seven tensor multiplets arise in these models.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
David Dunsky, Lawrence J. Hall, Keisuke Harigaya

Abstract An exact parity replicates the Standard Model giving a Mirror Standard Model, SM ↔ SM′. This “Higgs Parity” and the mirror electroweak symmetry are spontaneously broken by the mirror Higgs, 〈H′〉 = v′ ≫ 〈H〉, yielding the Standard Model Higgs as a Pseudo-Nambu-Goldstone Boson of an approximate SU (4) symmetry, with a quartic coupling λSM(v′) ∼ 10−3. Mirror electromagnetism is unbroken and dark matter is composed of e′ and $${\overline{e}}^{\prime }$$. Direct detection may be possible via the kinetic mixing portal, and in unified theories this rate is correlated with the proton decay rate. With a high reheat temperature after inflation, the et dark matter abundance is determined by freeze-out followed by dilution from decays of mirror neutrinos, ν′→ ℓH . Remarkably, this requires v′∼ (108–1010) GeV, predicting a Higgs mass of 123 ± 3 GeV at 1σ and a Standard Model neutrino mass of (10−2–10−1) eV, consistent with observed neutrino masses. The mirror QCD sector exhibits a first order phase transition producing gravitational waves that may be detected by future observations. Mirror glueballs decay to mirror photons giving dark radiation with ∆Neff∼ 0.03–0.4. With a low reheat temperature after inflation, the e′ dark matter abundance is determined by freeze-in from the SM sector by either the Higgs or kinetic mixing portal.

更新日期：2020-02-18
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
Evgeny I. Buchbinder, Andre Lukas, Burt A. Ovrut, Fabian Ruehle

Abstract We consider non-perturbative superpotentials from world-sheet instantons wrapped on holomorphic genus zero curves in heterotic string theory. These superpotential contributions feature prominently in moduli stabilization and large field axion inflation, which makes their presence or absence, as well as their functional dependence on moduli, an important issue. We develop geometric methods to compute the instanton superpotentials for heterotic string theory with monad and extension bundles. Using our methods, we find a variety of examples with a non-vanishing superpotential. In view of standard vanishing theorems, we speculate that these results are likely to be attributed to the non-compactness of the instanton moduli space. We test this proposal, for the case of monad bundles, by considering gauged linear sigma models where compactness of the instanton moduli space can be explicitly checked. In all such cases, we find that the geometric results are consistent with the vanishing theorems. Surprisingly, linearly dependent Pfaffians even arise for cases with a non-compact instanton moduli space. This suggests some gauged linear sigma models with a non-compact instanton moduli space may still have a vanishing instanton superpotential.

更新日期：2020-02-14
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
Yogesh Dandekar, Arunabha Saha

Abstract We derive the effective equations of the membranes dual to black holes in a particular theory of higher derivative gravity namely Einstein-Gauss-Bonnet (EGB) gravity at sub-leading order in 1/D upto linear order in the Gauss-Bonnet (GB) parameter β. We find an expression for an entropy current which satisfies a local version of second law onshell in this regime. We also derive the membrane equations upto leading order in 1/D but non-perturbatively in β for EGB gravity. In this regime we write down an expression for a world-volume stress tensor of the membrane and also work out the effective membrane equation for stationary black holes.

更新日期：2020-02-14
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
Akikazu Hashimoto, David Kutasov

Abstract We calculate the torus partition sum of a general CFT2 with left and right moving conserved currents J and $$\overline{J}$$, perturbed by a combination of the irrelevant operators $$T\overline{T},J\overline{T}$$ and $$T\overline{J}$$. We use string theory techniques to write it as an integral transform of the partition sum of the unperturbed CFT with chemical potentials for the left and right moving conserved charges. The resulting expression transforms in the right way under the modular group, and reproduces the known spectrum of these models. We also derive a formula for the partition function of deformed CFT2 with non-vanishing chemical potentials.

更新日期：2020-02-14
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-13
Stefan Antusch, Christian Hohl, Vasja Susič

Abstract Since SO(10) GUTs unify all fermions of the Standard Model plus a right-chiral neutrino in a representation 16 per family, they have the potential to be maximally predictive regarding the ratios between the masses (or Yukawa couplings) of different fermion types, i.e. the up-type quarks, down-type quarks, charged leptons and neutrinos. We analyze the predictivity of classes of SO(10) (SUSY) GUT models for the fermion mass ratios, where the Yukawa couplings for each family are dominated by a single effective GUT operator of the schematic form 162 · 45n · 210m · H, for H ∈ {10,120,$$\overline{\mathbf{126}}$$}. This extends previous works to general vacuum expectation value directions for GUT-scale VEVs and to larger Higgs representations. In addition, we show that the location of the MSSM Higgses in the space of all doublets is a crucial aspect to consider. We discuss highly predictive cases and illustrate the predictive power in toy models consisting of masses for the 3rd and 2nd fermion family.

更新日期：2020-02-14
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Robert Franken, Christian Schwinn

Abstract We perform a comprehensive study of on-shell recursion relations for Born amplitudes in spontaneously broken gauge theories and identify the minimal shifts required to construct amplitudes with a given particle content and spin quantum numbers. We show that two-line or three-line shifts are sufficient to construct all amplitudes with five or more particles, apart from amplitudes involving longitudinal vector bosons or scalars, which may require at most five-line shifts. As an application, we revisit selection rules for multi-boson amplitudes using on-shell recursion and little-group transformations.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-12
Hirotaka Hayashi, Sung-Soo Kim, Kimyeong Lee, Futoshi Yagi

Abstract For any 5d $$\mathcal{N}$$ = 1 superconformal field theory, we propose a “complete” prepotential which reduces to the perturbative prepotential for any of its possible gauge theory realizations, manifests its global symmetry when written in terms of the invariant Coulomb branch parameters, and is valid for the whole parameter region. As concrete examples, we consider SU(2) gauge theories with up to 7 flavors, Sp(2) gauge theories with up to 9 flavors, and Sp(2) gauge theories with 1 antisymmetric tensor and up to 7 flavors, as well as their dual gauge theories.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-11
Harold Erbin, Carlo Maccaferri, Jakub Vošmera

Abstract We consider the algebraic couplings in the tree level effective action of the heterotic string. We show how these couplings can be computed from closed string field theory. When the light fields we are interested in are charged under an underlying $$\mathcal{N}$$ = 2 R-charge in the left-moving sector, their quartic effective potential localizes at the boundary of the worldsheet moduli space, in complete analogy to the previously studied open string case. In particular we are able to compute the quartic closed string field theory potential without resorting to any explicit expression for the 3- and the 4-strings vertices but only using the L∞ relations between them. As a non trivial example we show how the heterotic Yang-Mills quartic potential arises in this way.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-11
Shamik Banerjee, Pranjal Pandey

Abstract Representations of the (Lorentz) conformal group with the soft operators as highest weight vectors have two universal properties, which we clearly state in this paper. Given a soft operator with a certain dimension and spin, the first property is about the existence of “(large) gauge transformation” that acts on the soft operator. The second property is the decoupling of (large) gauge-invariant null-states of the soft operators from the S-matrix elements. In each case, the decoupling equation has the form of zero field-strength condition with the soft operator as the (gauge) potential. Null-state decoupling effectively reduces the number of polarisation states of the soft particle and is crucial in deriving soft-theorems from the Ward identities of asymptotic symmetries. To the best of our understanding, these properties are not directly related to the Lorentz invariance of the S-matrix or the existence of asymptotic symmetries. We also verify that the results obtained from the decoupling of null-states are consistent with the leading and subleading soft-theorems with finite energy massive and massless particles in the external legs.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-11
Ralph Blumenhagen, Max Brinkmann, Andriana Makridou

Abstract Taking the anti-de Sitter minimum of KKLT and the large volume scenario at face value, we argue for the existence of logarithmic quantum corrections to AdS swampland conjectures. If these conjectures receive such corrections, it is natural to suspect that they also arise for other swampland conjectures, in particular the dS swampland conjecture. We point out that the proposed log-corrections are in accord with the implications of the recently proposed trans-Planckian censorship conjecture. We also comment on the emergence proposal in the context of both perturbative flux models and the KKLT construction.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-11
Fredrik Björkeroth, Luca Di Luzio, Federico Mescia, Enrico Nardi

Abstract The flavour neutrino puzzle is often addressed by considering neutrino mass matrices m with a certain number of vanishing entries (mij = 0 for some values of the indices), since a reduction in the number of free parameters increases the predictive power. Symmetries that can enforce textures zero can also enforce a more general type of conditions f(mij) = 0 with f some function of the matrix elements mij. In this case m can have all entries non-vanishing with no reduction in its predictive power. We classify all generation-dependent U(1) symmetries which, in the presence of two leptonic Higgs doublets, can reduce the number of independent high-energy parameters of type-I seesaw to the minimum number compatible with non-vanishing neutrino mixings and CP violation. These symmetries are broken above the scale where the effective operator is generated and can thus remain covert, in the sense that no explicit evidence of the symmetry can be read off the neutrino mass matrix, and different symmetries can give rise to the same low-energy structure. We find that only two cases are viable: one yields a structure with two zero-textures already considered in the literature, the other has no zero-textures and has never been considered before. It predicts normal ordering, a lightest neutrino mass ∼ 10 meV, a Dirac phase δ ∼ $$\frac{3\pi }{2}$$ and definite values for the Majorana phases.

更新日期：2020-02-13
• J. High Energy Phys. (IF 5.833) Pub Date : 2020-02-11
Marco Drewes, Jan Hajer

Abstract We study the sensitivity of displaced vertex searches for heavy neutrinos produced in W boson decays in the LHC detectors ATLAS, CMS and LHCb. We also propose a new search that uses the muon chambers to detect muons from heavy neutrino decays outside the tracker. The sensitivity estimates are based on benchmark models in which the heavy neutrinos mix exclusively with one of the three Standard Model generations. In the most sensitive mass regime the displaced vertex searches can improve existing constraints on the mixing with the first two SM generations by more than four orders of magnitude and by three orders of magnitude for the mixing with the third generation.

更新日期：2020-02-13
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