Thu·Aug 26, 2021Thursday·August 26, 2021

1. 01*

   Di-Higgs and tri-Higgs boson signals of muon $g-2$ at a muon collider

   Radovan Dermisek🇺🇸 · Keith Hermanek🇺🇸 · Navin McGinnis🇨🇦

   We show that new physics explanations of the muon $g-2$ anomaly by the contributions of new leptons mediated by the standard model Higgs boson necessarily lead to large rates for ${\mu }^{+}{\mu }^{-}\to hh$ and ${\mu }^{+}{\mu }^{-}\to hhh$ irrespectively of details of the model or the scale of new physics. For new leptons with the same quantum numbers as the standard model leptons, cross sections are expected to be about 240 ab for ${\mu }^{+}{\mu }^{-}\to hh$ independently of the center of mass energy, $\sqrt{s}$, and about 2.7 ab for ${\mu }^{+}{\mu }^{-}\to hhh$ for $\sqrt{s}=1$ TeV and growing quadratically with $\sqrt{s}$. Predictions for models featuring new leptons with different quantum numbers and for a type-II two Higgs doublet model, where additional Higgs bosons can contribute to muon $g-2$, are also presented.

   hep-phPRD(2021)·37 citations
2. 02*

   Revisiting Type-II see-saw: Present Limits and Future Prospects at LHC

   Saiyad Ashanujjaman🇮🇳 · Kirtiman Ghosh🇮🇳

   The type-II see-saw mechanism based on the annexation of the Standard Model by weak gauge triplet scalar field proffers a natural explanation for the very minuteness of neutrino masses. Noting that the phenomenology for the non-degenerate triplet Higgs spectrum is substantially contrasting than that for the degenerate one, we perform a comprehensive study for an extensive model parameter space parametrised by the triplet scalar vacuum expectation value (VEV), the mass-splitting between the triplet-like doubly and singly charged scalars and the mass of the doubly charged scalar. Considering all Drell-Yan production mechanisms for the triplet-like scalars and taking into account the all-encompassing complexity of their decays, we derive the most stringent 95% CL lower limits on the mass of the doubly charged scalar for a vast model parameter space by implementing already existing direct collider searches by CMS and ATLAS. These estimated limits are beyond those from the existing LHC searches by approximately 50-230 GeV. However, we also find that a specific region of the parameter space is not constrained by the LHC searches. Then, we forecast future limits by extending an ATLAS search at high-luminosity, and we propose a search strategy that yields improved limits for a part of the parameter space.

   hep-phhep-exJHEP(2022)·91 citations
3. 03*

   $SU(5)\times U(1{)}^{\prime }$ models with a vector-like fermion family

   A. Karozas🇬🇷 · G. K. Leontaris🇬🇷 · I. Tavellaris🇬🇷

   Motivated by experimental measurements indicating deviations from the Standard Model predictions we discuss F-theory inspired models, which, in addition to the three chiral generations contain a vector-like complete fermion family. The analysis takes place in the context of $SU(5)\times U(1{)}^{\prime }$ GUT embedded in an $E_8$ covering group which is associated with the (highest) geometric singularity of the elliptic fibration. In this context, the $U(1{)}^{\prime }$ is a linear combination of four abelian factors subjected to appropriate anomaly cancellation conditions. Furthermore, we require universal $U(1{)}^{\prime }$ charges for the three chiral families and different ones for the corresponding fields of the vector-like representations. Under the aforementioned assumptions, we find 192 such models which can be classified into five distinct categories with respect to their specific GUT properties. We exhibit representative examples for each such class and construct the superpotential couplings and the fermion mass matrices. We explore the implications of the vector-like states in low energy phenomenology including the predictions regarding the B-meson anomalies. The rôle of R-parity violating terms appearing in some particular models of the above construction is also discussed.

   hep-phUniverse(2021)·1 citation
4. 04*

   Spectra and decay properties of ${\Lambda }_b$ and ${\Sigma }_b$ baryons

   Amee Kakadiya🇮🇳 · Zalak Shah🇮🇳 · Keval Gandhi🇮🇳 · Ajay Kumar Rai🇮🇳

   In this article, we study the radial states as well as orbital states mass spectra of the nonstrange baryons from bottom family utilizing hypercentral Constituent Quark Model(hCQM), a non-relativistic approach by employing screened potential as confining potential with color Coulomb potential. The spin-spin, spin-orbital and tensor interaction are considered for hyperfine splitting calculation. The mass spectra calculated and compared with other theoretical approaches. The Regge trajectories has been plotted in $(J,M^2)$ plane using the calculated mass spectra. Further, the single-pion decay and radiative decay have been described and magnetic moments are determined for the ground state.

   hep-phFew Body Syst.(2022)·30 citations
5. 05*

   Probing charged lepton flavor violation with axion-like particles at Belle II

   Kingman Cheung🇹🇼 · Abner Soffer🇮🇱 · Zeren Simon Wang🇹🇼 · Yu-Heng Wu🇹🇼

   We study charged lepton flavor violation associated with a light leptophilic axion-like particle (ALP), $X$, at the $B$-factory experiment Belle II. We focus on production of the ALP in the tau decays $\tau \to Xl$ with $l=e,\mu$, followed by its decay via $X\to l^{-}{l}^{+}$. The ALP can be either promptly decaying or long-lived. We perform Monte-Carlo simulations, recasting a prompt search at Belle for lepton-flavor-violating $\tau$ decays, and propose a displaced-vertex (DV) search. For both types of searches, we derive the Belle~II sensitivity reaches in both the product of branching fractions and the ALP coupling constants, as functions of the ALP mass and lifetime. The results show that the DV search exceeds the sensitivity reach of the prompt search to the relevant branching fractions by up to about a factor of 40 in the long decay length regime.

   hep-phhep-exJHEP(2021)·41 citations
6. 06*

   Precision measurements and tau neutrino physics in a future accelerator neutrino experiment

   Jian Tang🇨🇳 · Sampsa Vihonen🇨🇳 · Yu Xu🇨🇳

   We investigate prospects of building a future accelerator-based neutrino oscillation experiment in China, including site selection, beam optimization and tau neutrino physics aspects. CP violation, non-unitary mixing and non-standard neutrino interactions are discussed. We simulate neutrino beam setups based on muon and beta decay techniques and compare Chinese laboratory sites by their expected sensitivities. A case study on Super Proton-Proton Collider and China JinPing Laboratory is also presented. It is shown that the muon-decay-based beam setup can measure the Dirac CP phase by about 14.2${}^{\circ }$ precision at 1$\sigma$ CL, whereas non-unitarity can be probed down to $|{\alpha }_{ij}|\lesssim$ 0.37 ($i\ne j=$ 1, 2, 3) and non-standard interactions to $|{ϵ}_{\ell {\ell }^{\prime }}^m|\lesssim$ 0.11 ($\ell \ne {\ell }^{\prime }=e$, $\mu$, $\tau$) at 90% CL, respectively.

   hep-phhep-exCommun.Theor.Phys.(2022)·9 citations
7. 07*

   Cosmological Relaxation through the Dark Axion Portal

   Valerie Domcke🇨🇭 · Kai Schmitz🇨🇭 · Tevong You🇨🇭

   The dark axion portal is a coupling of an axion-like particle to a dark photon kinetically mixed with the visible photon. We show how this portal, when applied to the relaxion, can lead to cosmological relaxation of the weak scale using dark photon production. The key backreaction mechanism involves the Schwinger effect: As long as electroweak symmetry is unbroken, Schwinger production of massless Standard Model fermions, which carry dark millicharges, suppresses the dark photon production. Once the electroweak symmetry is broken, the fermions acquire mass and the suppression is lifted. An enhanced dark photon dissipation then traps the relaxion at a naturally small weak scale. Our model thus provides a novel link between the phenomenological dark axion portal, dark photons, and the hierarchy problem of the Higgs mass.

   hep-phastro-ph.COJHEP(2022)·35 citations
8. 08*

   Anomalous couplings in $Z\gamma$ events at NNLO+PS and improving $\nu \bar{\nu }\gamma$ backgrounds in dark-matter searches

   Daniele Lombardi🇩🇪 · Marius Wiesemann🇩🇪 · Giulia Zanderighi🇩🇪

   The measurement of the triple gauge couplings (TGCs) is a central part of diboson studies at the LHC. In this letter we consider the $Z\gamma$ process and include anomalous TGCs (aTGCs) in the event generation at next-to-next-to-leading order QCD accuracy (NNLO+PS) within the MiNNLO${}_{\mathrm{PS}}$ framework. While our implementation is fully general and applies to both $Z\to {\ell }^{+}{\ell }^{-}$ and $Z\to \nu \bar{\nu }$ decays, we focus here on the $\nu \bar{\nu }\gamma$ final state. After validation of our simulation of $\nu \bar{\nu }\gamma$ events, for which NNLO+PS accuracy is achieved for the first time, the effects of aTGCs on various distributions are studied. Moreover, we show the relevance of NNLO+PS accuracy for the $\nu \bar{\nu }\gamma$ background to photon plus missing energy signatures in dark-matter searches, and we compare MiNNLO${}_{\mathrm{PS}}$ predictions for $\nu \bar{\nu }\gamma$ production to recent 13 TeV data.

   hep-phhep-exPLB(2022)·31 citations
9. 09*

   Constraints on Pseudo-Nambu-Goldstone dark matter from direct detection experiment and neutron star reheating temperature

   Yu-Pan Zeng🇨🇳 · Xiang Xiao🇨🇳 · Wei Wang🇨🇳

   Pseudo-Nambu-Goldstone dark matter connected to Standard Model fermion through the Higgs portal has the property that its direct detection vanishes in the zero momentum transfer limit due to a cancellation mechanism. This feature helps the Pseudo-Nambu-Goldstone dark matter to escape the stringent constraints from direct detection experiments. In this paper we explore new constraints on parameter space of non-zero momentum transfer from the direct detection experiments, and also from the neutron star temperature via the dark matter reheating mechanism.

   hep-phPLB(2022)·26 citations
10. 10*

    Missing Scalars at the Cosmological Collider

    Qianshu Lu🇺🇸 · Matthew Reece🇺🇸 · Zhong-Zhi Xianyu🇨🇳

    Light scalar fields typically develop spatially varying backgrounds during inflation. Very often they do not directly affect the density perturbations, but interact with other fields that do leave nontrivial signals in primordial perturbations. In this sense they become "missing scalars" at the cosmological collider. We study potentially observable signals of these missing scalars, focusing on a special example where a missing scalar distorts the usual oscillatory features in the squeezed bispectrum. The distortion is also a useful signal distinguishing the de Sitter background induced thermal mass from a constant intrinsic mass.

    hep-phastro-ph.COJHEP(2021)·66 citations
11. 11*

    Towards a Realistic Model of Dark Atoms to Resolve the Hubble Tension

    Nikita Blinov🇺🇸 · Gordan Krnjaic🇺🇸 · Shirley Weishi Li🇺🇸

    It has recently been shown that a subdominant hidden sector of atomic dark matter in the early universe provides a novel avenue towards resolving the Hubble ($H_0$) tension while maintaining good agreement with Cosmic Microwave Background era observables. However, such a mechanism requires a hidden sector whose energy density ratios are the same as in our sector and whose recombination also takes place at redshift $z\approx 1100$, which presents an apparent fine tuning. We introduce a realistic model of this scenario that dynamically enforces these coincidences without fine tuning. In our setup, the hidden sector contains an identical copy of Standard Model (SM) fields, but has a smaller Higgs vacuum expectation value (VEV) and a lower temperature. The baryon asymmetries and reheating temperatures in both sectors arise from the decays of an Affleck-Dine scalar field, whose branching ratios automatically ensure that the reheating temperature in each sector is proportional to the corresponding Higgs VEV. The same setup also naturally ensures that the Hydrogen binding energy in each sector is proportional to the corresponding VEV, so the ratios of binding energy to temperature are approximately equal in the two sectors. Furthermore, our scenario predicts a correlation between the SM/hidden temperature ratio and the atomic dark matter abundance and automatically yields values for these quantities favored by concordant early- and late-universe measurements of $H_0$.

    hep-phastro-ph.COPRD(2022)·31 citations
12. 12*

    The Electro-Weak Phase Transition at Colliders: Discovery Post-Mortem

    Andreas Papaefstathiou🇺🇸 · Graham White🇯🇵

    We explore the capabilities of a future proton collider to probe the nature of the electro-weak phase transition, following the hypothetical discovery of a new scalar particle. We focus on the real singlet scalar field extension of the Standard Model, representing the most minimal, and challenging to probe, framework that can enable a strong first-order electro-weak phase transition. By constructing detailed phenomenological methods for measuring the mass and accessible couplings of the new scalar particle, we find that a 100 TeV proton collider has the potential to explore the parameter space of the real singlet model and provide meaningful constraints on the electro-weak phase transition. We empirically find some necessary conditions for the realization of a strong first order electro-weak phase transition and conjecture that additional information, including through multi-scalar processes and gravitational wave detectors, are likely needed to gauge the nature of the cosmological electro-weak transition. This study represents the first crucial step towards solving the inverse problem in the context of the electro-weak phase transition.

    hep-phhep-exJHEP(2022)·17 citations
13. 13*

    Roads for Right-handed Neutrino Dark Matter: Fast Expansion, Standard Freeze-out, and Early Matter Domination

    Giorgio Arcadi🇮🇹 · Jacinto Paulo Neto🇧🇷 · Farinaldo S. Queiroz🇧🇷 · Clarissa Siqueira🇧🇷

    Right-handed neutrinos appear in several extensions beyond the Standard Model, specially in connection to neutrino masses. Motivated by this, we present a model of right-handed neutrino dark matter that interacts with Standard Model particles through a new gauge symmetry as well as via mass mixing between the new vector field and the Z boson, and investigate different production mechanisms. We derive the dark matter relic density when the Hubble rate is faster than usual, when dark matter decouples in a matter domination epoch, and when it decouples in a radiation domination regime, which is then followed by a matter domination era. The direct detection rate features a spin-independent but velocity suppressed operators, as well as a spin-dependent operator when the mass mixing is correctly accounted for. We put all these results into perspective with existing flavor physics, atomic parity violation, and collider bounds. Lastly, we outline the region of parameter space in which a weak scale right-handed neutrino dark matter stands as a viable dark matter candidate.

    hep-phPRD(2022)·20 citations
14. 14*

    Formal Aspects of Quantum Decay

    D. F. Ramírez Jiménez🇨🇴 · N. G. Kelkar🇨🇴

    The Fock-Krylov formalism for the calculation of survival probabilities of unstable states is revisited paying particular attention to the mathematical constraints on the density of states, the Fourier transform of which gives the survival amplitude. We show that it is not possible to construct a density of states corresponding to a purely exponential survival amplitude. he survival probability $P(t)$ and the autocorrelation function of the density of states are shown to form a pair of cosine Fourier transforms. This result is a particular case of the Wiener Khinchin theorem and forces $P(t)$ to be an even function of time which in turn forces the density of states to contain a form factor which vanishes at large energies. Subtle features of the transition regions from the non-exponential to the exponential at small times and the exponential to the power law decay at large times are discussed by expressing $P(t)$ as a function of the number of oscillations, $n$, performed by it. The transition at short times is shown to occur when the survival probability has completed one oscillation. The number of oscillations depend on the properties of the resonant state and a complete description of the evolution of the unstable state is provided by determining the limits on the number of oscillations in each region.

    ↳ quant-phhep-phnucl-thPRA(2021)·12 citations
15. 15*

    Virial halo mass function in the $Planck$ cosmology

    Masato Shirasaki🇯🇵 · Tomoaki Ishiyama🇯🇵 · Shin'ichiro Ando🇳🇱

    We study halo mass functions with high-resolution $N$-body simulations under a $\Lambda$CDM cosmology. Our simulations adopt the cosmological model that is consistent with recent measurements of the cosmic microwave backgrounds with the $Planck$ satellite. We calibrate the halo mass functions for 10^{8.5} \lower.5ex\hbox{\; \buildrel < \over \sim \;} M_\mathrm{vir} / (h^{-1}M_\odot) \lower.5ex\hbox{\; \buildrel < \over \sim \;} 10^{15.0 - 0.45 \, z}, where $M_{\mathrm{vir}}$ is the virial spherical overdensity mass and redshift $z$ ranges from $0$ to $7$. The halo mass function in our simulations can be fitted by a four-parameter model over a wide range of halo masses and redshifts, while we require some redshift evolution of the fitting parameters. Our new fitting formula of the mass function has a 5\%-level precision except for the highest masses at $z\le 7$. Our model predicts that the analytic prediction in Sheth $\&$ Tormen would overestimate the halo abundance at $z=6$ with $M_{\mathrm{vir}}=10^{8.5-10}{h}^{-1}{M}_{\odot }$ by $20-30\%$. Our calibrated halo mass function provides a baseline model to constrain warm dark matter (WDM) by high-$z$ galaxy number counts. We compare a cumulative luminosity function of galaxies at $z=6$ with the total halo abundance based on our model and a recently proposed WDM correction. We find that WDM with its mass lighter than $2.71\mathrm{keV}$ is incompatible with the observed galaxy number density at a $2\sigma$ confidence level.

    ↳ astro-ph.COastro-ph.GAhep-phApJ(2021)·20 citations
16. 16*

    Form factors for the processes $B_c^{+}\to D^0{\ell }^{+}{\nu }_{\ell }$ and $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}(\nu \overline{\nu })$ from lattice QCD

    Laurence J. Cooper🇬🇧 · Christine T. H. Davies🇬🇧 · Matthew Wingate🇬🇧

    We present results of the first lattice QCD calculations of the weak matrix elements for the decays $B_c^{+}\to D^0{\ell }^{+}{\nu }_{\ell }$, $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}$ and $B_c^{+}\to D_s^{+}\nu \overline{\nu }$. Form factors across the entire physical $q^2$ range are then extracted and extrapolated to the continuum limit with physical quark masses. Results are derived from correlation functions computed on MILC Collaboration gauge configurations with three different lattice spacings and including 2+1+1 flavours of sea quarks in the Highly Improved Staggered Quark (HISQ) formalism. HISQ is also used for all of the valence quarks. The uncertainty on the decay widths from our form factors is similar in size to that from the present value for $V_{ub}$. We obtain the ratio $\Gamma (B_c^{+}\to D^0{\mu }^{+}{\nu }_{\mu })/{\left|{\eta }_{\mathrm{EW}}{V}_{ub}\right|}^2=4.43(63)\times 10^{12}{\mathrm{s}}^{-1}$. Combining our form factors with those found previously by HPQCD for $B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu }$, we find ${\left|V_{cb}/V_{ub}\right|}^2\Gamma (B_c^{+}\to D^0{\mu }^{+}{\nu }_{\mu })/\Gamma (B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu })=0.257(36{)}_{B_c\to D}(18{)}_{B_c\to J/\psi }$. We calculate the differential decay widths of $B_c^{+}\to D_s^{+}{\ell }^{+}{\ell }^{-}$ across the full $q^2$ range, and give integrated results in $q^2$ bins that avoid possible effects from charmonium and $u\overline{u}$ resonances. For example, we find that the ratio of differential branching fractions integrated over the range $q^2=1{\mathrm{GeV}}^2-6{\mathrm{GeV}}^2$ for $B_c^{+}\to D_s^{+}{\mu }^{+}{\mu }^{-}$ and $B_c^{+}\to J/\psi {\mu }^{+}{\nu }_{\mu }$ is $5.23(73{)}_{B_c\to D_s}(54{)}_{B_c\to J/\psi }\times 10^{-6}$. We also give results for the branching fraction of $B_c^{+}\to D_s^{+}\nu \overline{\nu }$. Prospects for reducing our errors in the future are discussed.

    ↳ hep-lathep-phPRD(2022)·26 citations
17. 17*

    Azimuthal correlations of D mesons with charged particles in simulations with the ALICE experiment

    Eszter Frajna🇭🇺 · Robert Vertesi (for the ALICE experiment)🇭🇺

    In this manuscript, results of a component-level analysis with Monte Carlo simulations are presented, that aid the interpretation of recent ALICE results on the azimuthal correlation distribution of prompt D mesons with charged hadrons in pp and p--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV. Parton-level contributions and fragmentation properties are evaluated. Charm and beauty contributions are compared in order to identify the observables that serve as sensitive probes of the production and hadronization of heavy quarks.

    ↳ nucl-exhep-phParticles(2021)·0 citations
18. 18*

    Measurement of the branching fraction of ${\Lambda }_c^{+}\to p\omega$ decay at Belle

    Belle Collaboration: S. X. Li🇨🇳 · L. K. Li🇺🇸 · C. P. Shen🇨🇳 · I. Adachi🇯🇵 · H. Aihara🇯🇵 · S. Al Said🇸🇦 · D. M. Asner🇺🇸 · T. Aushev🇷🇺 · P. Behera🇮🇳 · K. Belous🇷🇺 · J. Bennett🇺🇸 · M. Bessner🇺🇸 and 183 other authors

    Using 980.6 $\mathrm{f}{\mathrm{b}}^{-1}$ of data collected with the Belle detector operating at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider, we present a measurement of the branching fraction of the singly Cabibbo-suppressed decay ${\Lambda }_c^{+}\to p\omega$. A clear ${\Lambda }_c^{+}$ signal is observed for ${\Lambda }_c^{+}\to p\omega$ with a statistical significance of 9.1 standard deviations, and we measure the ratio of branching fractions $\mathcal{B}({\Lambda }_c^{+}\to p\omega )/\mathcal{B}({\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+})=(1.32\pm 0.12(\mathrm{stat})\pm 0.10(\mathrm{syst}))\times 10^{-2}$, from which we infer the branching fraction $\mathcal{B}({\Lambda }_c^{+}\to p\omega )=(8.27\pm 0.75(\mathrm{stat})\pm 0.62(\mathrm{syst})\pm 0.42(\mathrm{ref}))\times 10^{-4}$. The first quoted uncertainty is statistical, the second systematic, and the third from the reference mode ${\Lambda }_c^{+}\to p{K}^{-}{\pi }^{+}$.

    ↳ hep-exhep-phPRD(2021)·17 citations
19. 19*

    The Effective Field Theory of Large-Scale Structure and Multi-tracer

    Thiago Mergulhão🇧🇷 · Henrique Rubira🇩🇪 · Rodrigo Voivodic🇧🇷 · L. Raul Abramo🇧🇷

    We study the performance of the perturbative bias expansion when combined with the multi-tracer technique, and their impact on the extraction of cosmological parameters. We consider two populations of tracers of large-scale structure and perform a series of Markov chain Monte Carlo analysis for those two tracers separately. The constraints in ${\omega }_{\mathrm{cdm}}$ and $h$ using multi-tracer are less biased and approximately $60\%$ better than those obtained for a single tracer. The multi-tracer approach also provides stronger constraints on the bias expansion parameters, breaking degeneracies between them and with their error being typically half of the single-tracer case. Finally, we studied the impacts caused in parameter extraction when including a correlation between the stochastic field of distinct tracers. We also include a study with galaxies showing that multi-tracer still lead to substantial gains in the cosmological parameters.

    ↳ astro-ph.COgr-qchep-phJCAP(2022)·26 citations
20. 20*

    Implementation of residual nucleus de-excitations associated with proton decays in ${}^{12}\mathrm{C}$ based on the GENIE generator and TALYS code

    Hang Hu🇨🇳 · Wan-Lei Guo🇨🇳 · Jun Su🇨🇳 · Wei Wang🇨🇳 · Cenxi Yuan🇨🇳

    We implement the de-excitation processes of residual nuclei associated with proton decays in ${}^{12}\mathrm{C}$ based on the GENIE generator and TALYS code. To derive the reasonable excitation energy spectra of residual nuclei ${}^{11}\mathrm{B}$, ${}^{10}\mathrm{B}$ and ${}^{10}\mathrm{Be}$, the default GENIE nucleon decay generator is modified in terms of the Spectral Function nuclear model. Then we use the TALYS code to estimate the de-excitation processes of residual nuclei. The TALYS calculation can partly account for the experimental data.

    ↳ nucl-thhep-exhep-phnucl-exPLB(2022)·8 citations
21. 21*

    The Weak Gravity Conjecture and Axion Strings

    Ben Heidenreich🇺🇸 · Matthew Reece🇺🇸 · Tom Rudelius🇺🇸

    Strong (sublattice or tower) formulations of the Weak Gravity Conjecture (WGC) imply that, if a weakly coupled gauge theory exists, a tower of charged particles drives the theory to strong coupling at an ultraviolet scale well below the Planck scale. This tower can consist of low-spin states, as in Kaluza-Klein theory, or high-spin states, as with weakly-coupled strings. We provide a suggestive bottom-up argument based on the mild $p$-form WGC that, for any gauge theory coupled to a fundamental axion through a $\theta F\wedge F$ term, the tower is a stringy one. The charge-carrying string states at or below the WGC scale $g{M}_{\mathrm{Pl}}$ are simply axion strings for $\theta$, with charged modes arising from anomaly inflow. Kaluza-Klein theories evade this conclusion and postpone the appearance of high-spin states to higher energies because they lack a $\theta F\wedge F$ term. For abelian Kaluza-Klein theories, modified arguments based on additional abelian groups that interact with the Kaluza-Klein gauge group sometimes pinpoint a mass scale for charged strings. These arguments reinforce the Emergent String and Distant Axionic String Conjectures. We emphasize the unproven assumptions and weak points of the arguments, which provide interesting targets for further work. In particular, a sharp characterization of when gauge fields admit $\theta F\wedge F$ couplings and when they do not would be immensely useful for particle phenomenology and for clarifying the implications of the Weak Gravity Conjecture.

    ↳ hep-thhep-phJHEP(2021)·54 citations
22. 22*

    Particle properties in the early universe from the contraction of the SM gauge group

    Nikolai A. Gromov🇷🇺

    The properties of elementary particles and their interactions at different stages of the evolution of the Universe, starting with the Planck energy $10^{19}$ GeV, are presented. We assume that the Standard Model gauge group becomes simpler as the temperature of the universe increases. The description is based on the hypothesis that the high-energy (high-temperature) limit of the Standard Model is generated by the contraction of the gauge group. An explicit form of the Lagrangian is obtained for each stage of the evolution of the universe and is the basis for describing the properties of elementary particles. These properties change drastically in the infinite temperature limit: all particles lose mass, only massless neutral $Z$ bosons and $u$ quarks, as well as neutrinos and photons, survive. Electroweak interactions become long range and are mediated by neutral currents. All quarks are monochromatic.

    ↳ physics.gen-phhep-ph0 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.