Wed·Feb 17, 2021Wednesday·February 17, 2021

1. 01*

   Proton mass decomposition: naturalness and interpretations

   Xiangdong Ji🇺🇸

   I discuss the scope and naturalness of the proton mass decomposition (or sum rule) published in PRL74, 1071 (1995) and answer a few criticisms that appeared recently in the literature, focusing particularly on its interpretation and the quantum anomalous energy contribution. I comment on the so-called frame-independent or invariant-mass decomposition from the trace of the energy-momentum tensor. I stress the importance of measuring the quantum anomalous energy through experiments. Finally, I point out a large discrepancy in the scalar radius of the nucleon extracted from vector-meson productions and lattice QCD calculations.

   hep-phhep-latnucl-exnucl-thFront.Phys.(Beijing)(2021)·104 citations
2. 02*

   Studying squark mass spectrum through gluino decay at 100 TeV future hadron colliders

   So Chigusa🇺🇸 · Koichi Hamaguchi🇯🇵 · Takeo Moroi🇯🇵 · Atsuya Niki🇯🇵 · Kosaku Ono🇯🇵

   We study the prospect of determining the decay properties of the gluino in the supersymmetric (SUSY) standard model at a 100 TeV future hadron collider. We consider the case where the neutral Wino is the lightest superparticle. In this case, the long-lived charged Wino can be used to eliminate standard model backgrounds, which enables us to study the details of superparticles. We show that, based on the analysis of the numbers of high $p_T$ leptons, boosted $W$-jets, and $b$-tagged jets, we may determine the gaugino species and the quark flavors in the gluino decay. With such determinations, we can obtain information about the mass spectrum of squarks even if squarks are out of the kinematical reach.

   hep-phhep-exPLB(2021)·2 citations
3. 03*

   Hunting for direct CP violation in ${\bar{B}}_s^0\to {\pi }^{+}{\pi }^{-}{K}^{\ast 0}$

   Sheng-Tao Li🇨🇳 · Gang Lü🇨🇳

   In perturbative QCD approach, based on the first order of isospin symmetry breaking, we study the direct $CP$ violation in the decay of ${\bar{B}}_s^0\to \rho (\omega )K^{\ast 0}\to {\pi }^{+}{\pi }^{-}{K}^{\ast 0}$. An interesting mechanism is applied to enlarge the $CP$ violating asymmetry involving the charge symmetry breaking between $\rho$ and $\omega$. We find that the $CP$ violation is large by the $\rho -\omega$ mixing mechanism when the invariant masses of the ${\pi }^{+}{\pi }^{-}$ pairs is in the vicinity of the $\omega$ resonance. For the decay process of ${\bar{B}}_s^0\to \rho (\omega )K^{\ast 0}\to {\pi }^{+}{\pi }^{-}{K}^{\ast 0}$, the maximum $CP$ violation can reach $-59.12\%$. Furthermore, taking $\rho -\omega$ mixing into account, we calculate the branching ratio for ${\bar{B}}_s^0\to \rho (\omega )K^{\ast 0}$. We also discuss the possibility of observing the predicted $CP$ violation asymmetry at the LHC.

   hep-phAdv.High Energy Phys.(2022)·2 citations
4. 04*

   Manifestations of non-zero Majorana CP violating phases in oscillations of supernova neutrinos

   Artem Popov🇷🇺 · Alexander Studenikin🇷🇺

   We investigate effects of non-zero Dirac and Majorana CP violating phases on neutrino-antineutrino oscillations in a magnetic field of astrophysical environments. It is shown that in the presence of strong magnetic fields and dense matter, non-zero CP phases can induce new resonances in the oscillations channels ${\nu }_e\leftrightarrow {\bar{\nu }}_e$, ${\nu }_e\leftrightarrow {\bar{\nu }}_{\mu }$ and ${\nu }_e\leftrightarrow {\bar{\nu }}_{\tau }$. We also consider all other possible oscillation channels with ${\nu }_{\mu }$ and ${\nu }_{\tau }$ in the initial state. The resonances can potentially lead to significant phenomena in neutrino oscillations accessible for observation in experiments. In particular, we show that neutrino-antineutrino oscillations combined with Majorana-type CP violation can affect the ${\bar{\nu }}_e$/${\nu }_e$ ratio for neutrinos coming from the supernovae explosion. This effect is more prominent for the normal neutrino mass ordering. The detection of supernovae neutrino fluxes in the future experiments, such as JUNO, DUNE and Hyper-Kamiokande, can give an insight into the nature of CP violation and, consequently, provides a tool for distinguishing the Dirac or Majorana nature of neutrinos.

   hep-phPRD(2021)·14 citations
5. 05*

   Structure of the meson Regge trajectories

   Jiao-Kai Chen🇨🇳

   We investigate the structure of the meson Regge trajectories based on the quadratic form of the spinless Salpeter-type equation. It is found that the forms of the Regge trajectories depend on the energy region. As the employed Regge trajectory formula does not match the energy region, the fitted parameters neither have explicit physical meanings nor obey the constraints although the fitted Regge trajectory can give the satisfactory predictions if the employed formula is appropriate mathematically. Moreover, the consistency of the Regge trajectories obtained from different approaches is discussed. And the Regge trajectories for different mesons are presented. Finally, we show that the masses of the constituents will come into the slope and explain why the slopes of the fitted linear Regge trajectories vary with different kinds of mesons.

   hep-phEPJA(2021)·27 citations
6. 06*

   Higgs $p_T$ Spectrum and Total Cross Section with Fiducial Cuts at Third Resummed and Fixed Order in QCD

   Georgios Billis🇩🇪 · Bahman Dehnadi🇩🇪 · Markus A. Ebert🇩🇪 · Johannes K. L. Michel🇺🇸 · Frank J. Tackmann🇩🇪

   We present predictions for the gluon-fusion Higgs $p_T$ spectrum at third resummed and fixed order (N${}^3$LL${}^{\prime }+$N${}^3$LO) including fiducial cuts as required by experimental measurements at the Large Hadron Collider. Integrating the spectrum, we predict for the first time the total fiducial cross section to third order (N${}^3$LO) and improved by resummation. The N${}^3$LO correction is enhanced by cut-induced logarithmic effects and is not reproduced by the inclusive N${}^3$LO correction times a lower-order acceptance. These are the highest-order predictions of their kind achieved so far at a hadron collider.

   hep-phhep-exPRL(2021)·110 citations
7. 07*

   Rapidity dependence of heavy-flavour production in heavy-ion collisions within a full 3+1 transport approach: quenching, elliptic and directed flow

   Andrea Beraudo🇮🇹 · Arturo De Pace🇮🇹 · Marco Monteno🇮🇹 · Marzia Nardi🇮🇹 · Francesco Prino🇮🇹

   We extend our POWLANG transport setup for the modelling of heavy-flavour production in heavy-ion collisions to the case of full 3+1 simulations, dropping the approximation of longitudinal boost-invariance of the background medium. This enables us to provide predictions for observables for which the rapidity dependence is essential in order to obtain a non-vanishing signal, like the directed flow $v_1$, and to get reliable results also for kinematic distributions of heavy-flavour particles at forward rapidity. We compare our predictions with experimental data obtained in Au-Au and Pb-Pb collisions at RHIC and at the LHC.

   hep-phnucl-exnucl-thJHEP(2021)·32 citations
8. 08*

   Diffusion coefficient matrix of the strongly interacting quark-gluon plasma

   Jan A. Fotakis🇩🇪 · Olga Soloveva🇩🇪 · Carsten Greiner🇩🇪 · Olaf Kaczmarek🇩🇪 · Elena Bratkovskaya🇩🇪

   We study the diffusion properties of the strongly interacting quark-gluon plasma (sQGP) and evaluate the diffusion coefficient matrix for the baryon ($B$), strange ($S$) and electric ($Q$) charges - ${\kappa }_{q{q}^{\prime }}$ ($q,q^{\prime }=B,S,Q$) and show their dependence on temperature $T$ and baryon chemical potential ${\mu }_B$. The non-perturbative nature of the sQGP is evaluated within the Dynamical Quasi-Particle Model (DQPM) which is matched to reproduce the equation of state of the partonic matter above the deconfinement temperature $T_c$ from lattice QCD. The calculation of diffusion coefficients is based on two methods: i) the Chapman-Enskog method for the linearized Boltzmann equation, which allows to explore non-equilibrium corrections for the phase-space distribution function in leading order of the Knudsen numbers as well as ii) the relaxation time approximation (RTA). In this work we explore the differences between the two methods. We find a good agreement with the available lattice QCD data in case of the electric charge diffusion coefficient (or electric conductivity) at vanishing baryon chemical potential as well as a qualitative agreement with the recent predictions from the holographic approach for all diagonal components of the diffusion coefficient matrix. The knowledge of the diffusion coefficient matrix is also of special interest for more accurate hydrodynamic simulations.

   hep-phnucl-thPRD(2021)·37 citations
9. 09*

   Mass sum rule of hadrons in the QCD instanton vacuum

   Ismail Zahed🇺🇸

   We briefly review the key aspect of the QCD instanton vacuum in relation to the quantum breaking of conformal symmetry and the trace anomaly. We use Ji${}^{\prime }s$ invariant mass decomposition of the energy momentum tensor together with the trace anomaly, to discuss the mass budget of the nucleon and pion in the QCD instanton vacuum. A measure of the gluon condensate in the nucleon, is a measure of the compressibility of the QCD instanton vacuum as a dilute topological liquid.

   hep-phhep-thPRD(2021)·23 citations
10. 10*

    Reduction of planar double-box diagram for single-top production via auxiliary mass flow

    Najam ul Basat🇨🇳 · Zhao Li🇨🇳 · Yefan Wang🇨🇳

    The single-top production is an important process at the LHC to test the Standard Model (SM) and search for the new physics beyond the SM. Although the complete next-to-next-to-leading order (NNLO) QCD correction to the single-top production is crucial, this calculation is still challenging at present. In order to efficiently reduce the NNLO single-top amplitude, we improve the auxiliary mass flow (AMF) method by introducing the $ϵ$ truncation. For demonstration we choose one typical planar double-box diagram for the $tW$ production. It is shown that one coefficient of the form factors on its amplitude can be systematically reduced into the linear combination of 198 scalar integrals.

    hep-phPRD(2021)·8 citations
11. 11*

    B-hadron hadro-production in NNLO QCD: application to LHC $t\bar{t}$ events with leptonic decays

    Michal Czakon🇩🇪 · Terry Generet🇩🇪 · Alexander Mitov🇬🇧 · Rene Poncelet🇬🇧

    We calculate, for the first time, the NNLO QCD corrections to identified heavy hadron production at hadron colliders. The calculation is based on a flexible numeric framework which allows the calculation of any distribution of a single identified heavy hadron plus jets and non-QCD particles. As a first application we provide NNLO QCD predictions for several differential distributions of $B$ hadrons in $t\bar{t}$ events at the LHC. Among others, these predictions are needed for the precise determination of the top quark mass. The extension of our results to other processes, like open or associated $B$ and charm production is straightforward. We also explore the prospects for extracting heavy flavor fragmentation functions from LHC data.

    hep-phhep-exJHEP(2021)·62 citations
12. 12*

    Texture of One Equality in Neutrino Mass Matrix

    A. Ismael🇪🇬 · E. I. Lashin🇪🇬 · M. AlKhateeb🇸🇾 · N. Chamoun🇸🇾

    We carry out a phenomenological and analytical study of the texture structures for the Majorana neutrino mass matrix characterized by one single equality between two independent matrix elements, with vanishing non-physical phases whose role in the definition we clarify. We find that fourteen textures are viable in both types of hierarchy, whereas the remaining fifteenth one is viable only in normal hierarchy. We also present symmetry realizations for some patterns by using Abelian flavor symmetries within type-I, type-II and mixed type-(I+II) seesaw scenarios.

    hep-phNPB(2021)·9 citations
13. 13*

    Four lepton production in gluon fusion: off-shell Higgs effects in NLO QCD

    Massimiliano Grazzini🇨🇭 · Stefan Kallweit🇮🇹 · Marius Wiesemann🇩🇪 · Jeong Yeon Yook🇨🇭

    We consider the production of four charged leptons in hadron collisions and compute the next-to-leading order (NLO) QCD corrections to the loop-induced gluon fusion contribution by consistently accounting for the Higgs boson signal, its corresponding background and their interference. The contribution from heavy-quark loops is exactly included in the calculation except for the two-loop $gg\to ZZ\to 4\ell$ continuum diagrams, for which the unknown heavy-quark effects are approximated through a reweighting procedure. Our calculation is combined with the next-to-next-to-leading order QCD and NLO electroweak corrections to the $q\bar{q}\to 4\ell$ process, including all partonic channels and consistently accounting for spin correlations and off-shell effects. The computation is implemented in the MATRIX framework and allows us to separately study the Higgs boson signal, the background and the interference contributions, whose knowledge can be used to constrain the Higgs boson width through off-shell measurements. Our state-of-the-art predictions for the invariant-mass distribution of the four leptons are in good agreement with recent ATLAS data.

    hep-phhep-exPLB(2021)·21 citations
14. 14*

    Inelastic dark matter scattering off Thallium cannot save DAMA

    Sunniva Jacobsen🇸🇪 · Katherine Freese🇸🇪 · Chris Kelso🇺🇸 · Pearl Sandick🇺🇸 · Patrick Stengel🇸🇪

    We study the compatibility of the observed DAMA modulation signal with inelastic scattering of dark matter (DM) off of the $0.1\%$ Thallium (Tl) dopant in DAMA. In this work we test whether there exist regions of parameter space where the Tl interpretation gives a good fit to the most recent data from DAMA, and whether these regions are compatible with the latest constraints from other direct detection experiments. Previously, Chang et al. in 2010, had proposed the Tl interpretation of the DAMA data, and more recently (in 2019) the DAMA/LIBRA collaboration found regions in parameter space of Tl inelastic scattering that differ by more than $10\sigma$ from a no modulation hypothesis. We have expanded upon their work by testing whether the regions of parameter space where inelastic DM-Tl scattering gives a good fit to the most recent DAMA data survive the constraints placed by the lack of a DM signal in XENON1T and CRESST-II. In addition, we have tested how these regions change with the main sources of uncertainty: the Tl quenching factor, which has never been measured directly, and the astrophysical uncertainties in the DM distribution. We conclude that inelastic DM scattering off Tl cannot explain the DAMA data in light of null results from other experiments.

    hep-phJCAP(2021)·6 citations
15. 15*

    Topological Obstructions to Autoencoding

    Joshua Batson🇺🇸 · C. Grace Haaf🇨🇳 · Yonatan Kahn🇺🇸 · Daniel A. Roberts🇺🇸

    Autoencoders have been proposed as a powerful tool for model-independent anomaly detection in high-energy physics. The operating principle is that events which do not belong to the space of training data will be reconstructed poorly, thus flagging them as anomalies. We point out that in a variety of examples of interest, the connection between large reconstruction error and anomalies is not so clear. In particular, for data sets with nontrivial topology, there will always be points that erroneously seem anomalous due to global issues. Conversely, neural networks typically have an inductive bias or prior to locally interpolate such that undersampled or rare events may be reconstructed with small error, despite actually being the desired anomalies. Taken together, these facts are in tension with the simple picture of the autoencoder as an anomaly detector. Using a series of illustrative low-dimensional examples, we show explicitly how the intrinsic and extrinsic topology of the dataset affects the behavior of an autoencoder and how this topology is manifested in the latent space representation during training. We ground this analysis in the discussion of a mock "bump hunt" in which the autoencoder fails to identify an anomalous "signal" for reasons tied to the intrinsic topology of $n$-particle phase space.

    hep-phcs.LGstat.MLJHEP(2021)·47 citations
16. 16*

    Heavy Higgs Bosons in 2HDM at a Muon Collider

    Tao Han🇺🇸 · Shuailong Li🇺🇸 · Shufang Su🇺🇸 · Wei Su🇦🇺 · Yongcheng Wu🇺🇸

    We study the discovery potential of the non-Standard Model (SM) heavy Higgs bosons in the Two-Higgs-Doublet Models (2HDMs) at a multi-TeV muon collider and explore the discrimination power among different types of 2HDMs. We find that the pair production of the non-SM Higgs bosons via the universal gauge interactions is the dominant mechanism once above the kinematic threshold. Single Higgs boson production associated with a pair of heavy fermions could be important in the parameter region with enhanced Yukawa couplings. For both signal final states, ${\mu }^{+}{\mu }^{-}$ annihilation channels dominate over the vector boson fusion (VBF) processes, except at high center of mass energies where the VBF processes receive large logarithmic enhancement with the increase of energies. Single Higgs boson $s$-channel production in ${\mu }^{+}{\mu }^{-}$-annihilation via the radiative return can also be important for the Type-L 2HDM in the very large $\tan \beta$ region, extending the kinematic reach of the heavy Higgs boson mass to the collider energy. Considering both the production and decay of non-SM Higgs bosons, signals can be identified over the Standard Model backgrounds. With the pair production channels via annihilation, 95\% C.L. exclusion reaches in the Higgs mass up to the production mass threshold of $\sqrt{s}/2$ are possible when channels with different final states are combined. Including single production modes can extended the reach further. Different types of 2HDMs can be distinguishable for moderate and large values of $\tan \beta$.

    hep-phhep-exPRD(2021)·84 citations
17. 17*

    Matching NNLO to parton shower using N${}^3$LL colour-singlet transverse momentum resummation in GENEVA

    Simone Alioli🇮🇹 · Christian W. Bauer🇺🇸 · Alessandro Broggio🇮🇹 · Alessandro Gavardi🇮🇹 · Stefan Kallweit🇮🇹 · Matthew A. Lim🇮🇹 · Riccardo Nagar🇮🇹 · Davide Napoletano🇮🇹 · Luca Rottoli🇨🇭

    We extend the GENEVA Monte Carlo framework using the transverse momentum of a colour-singlet system as the resolution variable. This allows us to use next-to-next-to-next-to leading logarithm (N${}^3$LL) resummation via the \radish formalism to obtain precise predictions for any colour-singlet production process at the fully exclusive level. Thanks to the implementation of two different resolution variables within the GENEVA framework, we are able to assess the impact of such a choice on differential observables for the first time. As a first application we present predictions for Drell-Yan lepton pair production at next-to-next-to-leading order (NNLO) in QCD interfaced to a parton shower simulation that includes additional all-order radiative corrections. We provide fully showered and hadronised events using PYTHIA8, while retaining the NNLO QCD accuracy for observables which are inclusive over the additional radiation. We also show that it is possible to obtain a numerically good agreement between showered GENEVA predictions and the N${}^3$LL resummation for the transverse momentum spectrum by choosing a more local recoil scheme. We compare our final predictions to LHC data at 13 TeV, finding good agreement across several distributions.

    hep-phhep-exPRD(2021)·66 citations
18. 18*

    Challenging the Stability of Light Millicharged Dark Matter

    Joerg Jaeckel🇩🇪 · Sebastian Schenk🇬🇧

    We investigate the cosmological stability of light bosonic dark matter carrying a tiny electric charge. In the wave-like regime of high occupation numbers, annihilation into gauge bosons can be drastically enhanced by parametric resonance. The millicharged particle can either be minimally coupled to photons or its electromagnetic interaction can be mediated via kinetic mixing with a massless hidden photon. In the case of a direct coupling current observational constraints on the millicharge are stronger than those arising from parametric resonance. For the (theoretically preferred) case of kinetic mixing large regions of parameter space are affected by the parametric resonance leading at least to a fragmentation of the dark matter field if not its outright destruction.

    hep-phastro-ph.COPRD(2021)·17 citations
19. 19*

    Unveiling the $K_1(1270)$ double-pole structure in the $\bar{B}\to J/\psi \rho \bar{K}$ and $\bar{B}\to J/\psi {\bar{K}}^{\ast }\pi$ decays

    J. M. Dias🇲🇽 · G. Toledo🇲🇽 · L. Roca🇪🇸 · E. Oset🇪🇸

    By looking at the pseudoscalar-vector meson spectra in the $\bar{B}\to J/\psi \rho \bar{K}$ and $\bar{B}\to J/\psi {\bar{K}}^{\ast }\pi$ weak decays, we theoretically investigate the double-pole structure of the $K_1(1270)$ resonance by using the Chiral Unitary approach to account for the final state interactions between the pseudoscalar and vector mesons. The $K_1(1270)$ resonance appears as dynamically generated through these interactions in coupled channels and influence the shape of the invariant mass distributions under consideration. We show how those shapes are affected by the $K_1(1270)$ double-pole structure to confront the results from our model with future experiments that might investigate the $PV$ spectra in these decays.

    hep-phPRD(2021)·29 citations
20. 20*

    Doubly hidden $0^{++}$ molecules and tetraquarks states from QCD at NLO

    R. M. Albuquerque · S. Narison · A. Rabemananjara · D. Rabetiarivony · G. Randriamanatrika

    Motivated by the LHCb-group discovery of exotic hadrons in the range (6.2 $\sim$ 6.9) GeV, we present new results for the masses and couplings of $0^{++}$ fully heavy $(\bar{Q}Q)(Q\bar{Q})$ molecules and $(QQ)(\overline{QQ})$ tetraquaks states from relativistic QCD Laplace Sum Rule (LSR) within stability criteria where Next-to-Leading Order (NLO) Factorized (F) Perturbative (PT) corrections is included. As the Operator Product Expansion (OPE) usually converges for $d⩽6-8$, we evaluated the QCD spectral functions at Lowest Order (LO) of PT QCD and up to $⟨G^3⟩$. We also emphasize the importance of PT radiative corrections for heavy quark sum rules in order to justify the use of the running heavy quark mass value in the analysis. We compare our predictions in Table 3 with the ones from ratio of Moments (MOM). The broad structure arround (6.2 $\sim$ 6.9) GeV can be described by the ${\overline{\eta }}_c{\eta }_c$, $\overline{J/\psi }J/\psi$ and ${\overline{\chi }}_{c1}{\chi }_{c1}$ molecules or/and ${\overline{S}}_c{S}_c$, ${\overline{A}}_c{A}_c$ and ${\overline{V}}_c{V}_c$ tetraquarks lowest mass ground states. The narrow structure at (6.8 $\sim$ 6.9) GeV if it is a $0^{++}$ state can be a ${\overline{\chi }}_{c0}{\chi }_{c0}$ molecules or/and its analogue ${\overline{P}}_c{P}_c$ tetraquark. The ${\overline{\chi }}_{c1}{\chi }_{c1}$ predicted mass is found to be below the ${\chi }_{c1}{\chi }_{c1}$ threshold while for the beauty states, all of the estimated masses are above the ${\eta }_b{\eta }_b$ and ${\rm Y}(1S){\rm Y}(1S)$ threshold.

    hep-phhep-exNucl.Part.Phys.Proc.(2021)·15 citations
21. 21*

    Accessing the shape of atomic nuclei with relativistic collisions of isobars

    Giuliano Giacalone🇩🇪 · Jiangyong Jia🇺🇸 · Vittorio Somà🇫🇷

    Nuclides sharing the same mass number (isobars) are observed ubiquitously along the stability line. While having nearly identical radii, stable isobars can differ in shape, and present in particular different quadrupole deformations. We show that even small differences in these deformations can be probed by relativistic nuclear collisions experiments, where they manifest as deviations from unity in the ratios of elliptic flow coefficients taken between isobaric systems. Collider experiments with isobars represent, thus, a unique means to obtain quantitative information about the geometric shape of atomic nuclei.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2021)·52 citations
22. 22*

    Comparison of cosmic string and superstring models to NANOGrav 12.5-year results

    Jose J. Blanco-Pillado🇪🇸 · Ken D. Olum🇺🇸 · Jeremy M. Wachter🇺🇸

    We compare the spectrum of the stochastic gravitational wave background produced in several models of cosmic strings with the common-spectrum process recently reported by NANOGrav. We discuss theoretical uncertainties in computing such a background, and show that despite such uncertainties, cosmic strings remain a good explanation for the potential signal, but the consequences for cosmic string parameters depend on the model. Superstrings could also explain the signal, but only in a restricted parameter space where their network behavior is effectively identical to that of ordinary cosmic strings.

    ↳ astro-ph.COgr-qchep-phPRD(2021)·98 citations
23. 23*

    Dark matter admixed neutron stars

    Ben Kain🇺🇸

    Neutron stars could contain a mixture of ordinary nuclear matter and dark matter, such that dark matter could influence observable properties of the star, such as its mass and radius. We study these dark matter admixed neutron stars for two choices of dark matter: a free Fermi gas and mirror dark matter. In addition to solving the multi-fluid Tolman-Oppenheimer-Volkoff equations for static solutions and presenting mass-radius diagrams, we focus on two computations that are lacking in the literature. The first is a rigorous determination of stability over the whole of parameter space, which we do using two different methods. The first method is based on harmonic time-dependent perturbations to the static solutions and on solving for the radial oscillation frequency. The second method, which is less well-known, conveniently makes use of unperturbed, static solutions only. The second computation is of the radial oscillation frequency, for fundamental modes, over large swaths of parameter space.

    ↳ gr-qcastro-ph.HEhep-phPRD(2021)·115 citations
24. 24*

    Exploring the Landscape for Soft Theorems of Nonlinear Sigma Models

    Laurentiu Rodina🇫🇷 · Zhewei Yin🇺🇸

    We generalize soft theorems of the nonlinear sigma model beyond the $\mathcal{O}(p^2)$ amplitudes and the coset of $\text{SU}(N)\times \text{SU}(N)/\text{SU}(N)$. We first discuss the universal flavor ordering of the amplitudes for the Nambu-Goldstone bosons, so that we can reinterpret the known $\mathcal{O}(p^2)$ single soft theorem for $\text{SU}(N)\times \text{SU}(N)/\text{SU}(N)$ in the context of a general symmetry group representation. We then investigate the special case of the fundamental representation of $\text{SO}(N)$, where a special flavor ordering of the "pair basis" is available. We provide novel amplitude relations and a Cachazo-He-Yuan formula for such a basis, and derive the corresponding single soft theorem. Next, we extend the single soft theorem for a general group representation to $\mathcal{O}(p^4)$, where for at least two specific choices of the $\mathcal{O}(p^4)$ operators, the leading non-vanishing pieces can be interpreted as new extended theory amplitudes involving bi-adjoint scalars, and the corresponding soft factors are the same as at $\mathcal{O}(p^2)$. Finally, we compute the general formula for the double soft theorem, valid to all derivative orders, where the leading part in the soft momenta is fixed by the $\mathcal{O}(p^2)$ Lagrangian, while any possible corrections to the subleading part are determined by the $\mathcal{O}(p^4)$ Lagrangian alone. Higher order terms in the derivative expansion do not contribute any new corrections to the double soft theorem.

    ↳ hep-thhep-phJHEP(2021)·19 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.