Tue·Sep 21, 2021Tuesday·September 21, 2021

1. 01*

   Fermiophobic $Z^{\prime }$ model for simultaneously explaining the muon anomalies $R_{K^{(\ast )}}$ and $(g-2{)}_{\mu }$

   Mario Fernández Navarro🇬🇧 · Stephen F. King🇬🇧

   We discuss a simple renormalisable, gauge invariant model with a fermiophobic $Z^{\prime }$ boson: it has no couplings to the three Standard Model (SM) chiral families, but does couple to a fourth vector-like (VL) family. The SM Higgs couples to the fourth VL lepton, leading to an enhanced contribution to the muon anomalous magnetic moment ${\left(g-2\right)}_{\mu }$. The latter contribution requires a non-vanishing coupling of $Z^{\prime }$ to right-handed muons, which arises within this model due to mixing effects between the SM and VL fermions, along with $Z^{\prime }$ couplings to the second generation SM lepton doublet and third generation SM quark doublet. This model can simultaneously account for the measured $B$-decay ratios $R_{K^{(\ast )}}$ and ${\left(g-2\right)}_{\mu }$. We identify the parameter space where this explanation is consistent with existing experimental constraints coming from $B_s-{\bar{B}}_s$ mixing, neutrino trident production and collider searches. We also check that the SM Higgs coupling to the fourth VL lepton does not produce a dangerous contribution to the Higgs diphoton decay.

   hep-phPRD(2022)·22 citations
2. 02*

   Pauli radius of the proton

   Zhu-Fang Cui🇨🇳 · Daniele Binosi🇮🇹 · Craig D. Roberts🇨🇳 · Sebastian M. Schmidt🇩🇪

   Using a procedure based on interpolation via continued fractions supplemented by statistical sampling, we analyse proton magnetic form factor data obtained via electron+proton scattering on $Q^2\in [0.027,0.55]$GeV${}^2$ with the goal of determining the proton magnetic radius. The approach avoids assumptions about the function form used for data interpolation and ensuing extrapolation onto $Q^2\simeq 0$ for extraction of the form factor slope. In this way, we find $r_M=0.817(27)$fm. Regarding the difference between proton electric and magnetic radii calculated in this way, extant data are seen to be compatible with the possibility that the slopes of the proton Dirac and Pauli form factors, $F_{1,2}(Q^2)$, are not truly independent observables; to wit, the difference $F_1^{\prime }(0)-F_2^{\prime }(0)/{\kappa }_p=[1+{\kappa }_p]/[4m_p^2]$, viz. the proton Foldy term.

   hep-phhep-exhep-latnucl-ex+1Chin.Phys.Lett.(2021)·11 citations
3. 03*

   Non-linear corrections to the longitudinal structure function $F_L$ from the parametrization of $F_2$: Laplace transform approach

   G.R.Boroun🇮🇷

   The non-linear corrections (NLC) to the longitudinal structure function in a limited approach is derived at low values of the Bjorken variable $x$ by using the Laplace transforms technique. The non-linear behavior of the longitudinal structure function is determined with respect to the Gribov-Levin-Ryskin Mueller-Qiu (GLR-MQ) and Altarelli-Martinelli (AM) equations. These results show that the non-linear longitudinal structure function can be determined directly in terms of the parametrization of $F_2(x,Q^2)$ and the derivative of the proton structure function with respect to $\ln Q^2$. These corrections improve the behavior of the longitudinal structure function at low values of $Q^2$ in comparison with other parametrization methods.

   hep-phEur.Phys.J.Plus(2022)·3 citations
4. 04*

   Kinetic theory of overpopulated gluon systems with inelastic processes

   Zhengyu Chen🇨🇳

   In this work, the role of inelastic processes in the formation of a transient Bose-Einstein condensation (BEC) is investigated based on kinetic theory. We calculate the condensation rate for an overpopulated gluon system which is assumed to be in thermal equilibrium and with the presence of a BEC. The matrix elements of the inelastic processes are chosen as the isotropic one and the gluons are considered to have a finite mass. Our calculations indicate that the inelastic processes can hinder the formation of a BEC since the negatively infinite net condensation rate can destroy any BEC instantly.

   hep-phnucl-thIJMPE(2023)·0 citations
5. 05*

   Charged Lepton EDM with Extra Yukawa Couplings

   Wei-Shu Hou🇹🇼 · Girish Kumar🇹🇼 · Sven Teunissen🇹🇼

   In a two Higgs doublet model with extra Yukawa couplings, we assess the new physics contributions to charged lepton electric dipole moment. We focus especially on muon (and tau) EDM where in the coming decade several experiments $-$ Muon g-2, J-PARC and PSI (and Belle II) $-$ will push sensitivities down by several orders of magnitude. With the working assumption that extra Yukawa couplings are analogous to SM ones in strength and taking exotic scalar masses in sub-TeV range, we find that $\mu$ and $\tau$ EDM can be enhanced to values larger than new physics scenarios that scale with lepton mass. The main effect comes from the flavor-conserving extra top coupling ${\rho }_{tt}$ via well-known two-loop diagrams. Deviating from our working assumption, if the muon $g-2$ anomaly arises from the one-loop diagram, driven by singly enhanced lepton flavor violating ${\rho }_{\tau \mu }$ coupling, it can also induce rather large muon EDM, accessible at upcoming experiments.

   hep-phJHEP(2022)·22 citations
6. 06*

   Spectral splits and entanglement entropy in collective neutrino oscillations

   Amol V. Patwardhan🇺🇸 · Michael J. Cervia🇺🇸 · A. B. Balantekin🇺🇸

   In environments such as core-collapse supernovae, neutron star mergers, or the early universe, where the neutrino fluxes can be extremely high, neutrino-neutrino interactions are appreciable and contribute substantially to their flavor evolution. Such a system of interacting neutrinos can be regarded as a quantum many-body system, and prospects for nontrivial quantum correlations, i.e., entanglement, developing in a gas of interacting neutrinos have been investigated previously. In this work, we uncover an intriguing connection between the entropy of entanglement of individual neutrinos with the rest of the ensemble, and the occurrence of spectral splits in the energy spectra of these neutrinos, which develop as a result of collective neutrino oscillations. In particular, for various types of neutrino spectra, we demonstrate that the entanglement entropy is highest for the neutrinos whose locations in the energy spectrum are closest to the spectral split(s). This trend demonstrates that the quantum entanglement is strongest among the neutrinos that are close to these splits, a behavior that seems to persist even as the size of the many-body system is increased.

   hep-phastro-ph.HEnucl-thquant-phPRD(2021)·63 citations
7. 07*

   Mesons and Baryons: Parity Partners

   L.X. Gutiérrez-Guerrero🇲🇽 · G. Paredes-Torres🇲🇽 · A. Bashir🇲🇽

   We calculate masses of light and heavy mesons as well as baryons of negative parity containing $u,d,s,c$ and $b$ quarks. It is an extension of our previous work where we had studied the positive parity baryons. We adopt a quark-diquark picture of baryons where the diquarks are non-pointlike with a finite spatial extension. The mathematical foundation for this analysis is implemented through a symmetry-preserving Schwinger-Dyson equations treatment of a vector-vector contact interaction, which preserves key features of quantum chromodynamics, such as confinement, chiral symmetry breaking, axial vector Ward-Takahashi identity and low-energy Goldberger-Treiman relations. This treatment simultaneously describes mesons and provides attractive correlations for diquarks in the $\overline{3}$ representation. Employing this model, we compute the spectrum and masses of all spin-1/2 and spin-3/2 baryons of negative parity, supplementing our earlier evaluation of positive parity baryons, containing 1, 2 or 3 heavy quarks. In the process, we calculate masses of a multitude of mesons and corresponding diquarks. Wherever possible, we make comparisons of our results with known experimental observations as well as theoretical predictions of several models and approaches including lattice quantum chromodynamics, finding satisfactory agreement. We also make predictions for heavier states not yet observed in the experiment.

   hep-phnucl-thPRD(2021)·37 citations
8. 08*

   Dark Matter, Cosmic Positrons in Alpha Magnetic Spectrometer Experiment and Particle-Cosmology with Yang-Mills Gravity

   Jong-Ping Hsu🇺🇸 · Leonardo Hsu🇺🇸

   We discuss a model of dark matter consisting of high energy anti-electron-neutrinos with leptonic force, which is produced by the conserved leptonic charge $g_{\ell }$ associated with Lee-Yang's $U_1$ gauge symmetry. Based on particle-cosmology for early universe, the high energy neutrino (HEN) model of dark matter assumes that the neutron decay processes, $n\to p^{+}+e^{-}+\text{ov}{\nu }_e$, dominate the epoch after the creation, collision and confinement processes of quarks and antiquarks in the beginning. The HEN model implies the following results: There are almost equal numbers of electrons, protons and anti-electron-neutrinos dominated the matter cosmos. There are unobservable and ubiquitous anti-electron-neutrinos $\text{ov}{\nu }_e$ with leptonic charge $g_{\ell }$ in the universe. Although the total mass of anti-electron-neutrino dark matter is negligible in the universe, its enhanced gravitational and leptonic forces could lead to the observed flat rotation curves due to relativistic $\text{ov}{\nu }_e$, whose static force involves a factor $E_{\nu }/m_{\nu }\approx 10^6$. We estimate the leptonic charge to be $g_{\ell }\approx 7\times 10^{-21}$. The model predicts that the anti-electron-neutrino dark matter can interact with cosmic-ray protons to produce positrons, i.e. $\text{ov}{\nu }_e+p^{+}\to e^{+}+n$, through weak interaction of the unified electroweak theory. The anti-electron-neutrino dark matter sheds light on the Alpha Magnetic Spectrometer (AMS) experiment, which has detected the intriguing excess of cosmic-ray positrons over what is expected. The HEN model of dark matter suggests an experimental test of the new Lee-Yang force between electrons by using modern precision Cavendish experiment.

   hep-phgr-qchep-thChin.J.Phys.(2021)·0 citations
9. 09*

   Multiplicity, probabilities, and canonical sectors for the cold QCD matter

   Kouji Kashiwa🇯🇵 · Hiroaki Kouno🇯🇵

   At sufficiently low temperature, without requiring any numerical data at finite real chemical potential, we can clarify the canonical partition function with fixed quark number via the imaginary chemical potential region with few ansatzs. The canonical partition function relates to the multiplicity distribution which can be observed in collider experiments and thus we may access important information of the properties of the QCD matter based on the canonical method. In this paper, we estimate the multiplicity entropy, the configuration entropy, and the pointwise information which can be calculable with the canonical partition function to understand the properties of the cold QCD matter at finite density. With the large $N_{\mathrm{c}}$ limit where $N_{\mathrm{c}}$ is the number of colors, we can simply estimate the tendency of them, and then the relation to the quarkyonic phase is clarified. In addition, we discuss the nontrivial ground state degeneracy from the viewpoint of the canonical sectors.

   hep-phPRD(2022)·6 citations
10. 10*

    Magnetic moment of the ${\Xi }_b(6227)$ as a molecular pentaquark state

    U. Ozdem🇹🇷

    In this study, considering that the ${\Xi }_b(6227)$ state is in molecular structure, the magnetic moment of this state is extracted in the light-cone QCD sum rules. The numerical result is obtained as ${\mu }_{{\Xi }_b}=0.12\pm 0.03{\mu }_N$. The magnetic moment of this state contains important information of its internal structure and shape deformations. Measurement of the magnetic moment of the ${\Xi }_b(6227)$ state in future experimental facilities can be very helpful in identification of the quantum numbers, as well as comprehension of the inner structure of this state.

    hep-phhep-exhep-latEur.Phys.J.Plus(2022)·11 citations
11. 11*

    Breaking down the entire spectrum of spin correlations of a pair of particles involving fermions and gauge bosons

    Rafiqul Rahaman🇮🇳 · Ritesh K. Singh🇮🇳

    We discuss a formalism for the spin correlations and polarizations in two-particle systems with spins half-half, half-one and one-one, and provide the connections between the polarizations and correlations with the joint angular distributions of decay products identifying the asymmetries for them. We demonstrate the formalism in the processes $e^{-}{e}^{+}\to t\bar{t}$, $gb\to t{W}^{-}$ and $e^{-}{e}^{+}\to ZZ$ in the standard model as examples. We investigate the effect of some anomalous couplings on the polarizations and spin correlations in the processes $e^{-}{e}^{+}\to t\bar{t}$, $gb\to t{W}^{-}$ and $u\bar{d}\to Z{W}^{+}$ at parton level and compare their strengths. The spin correlations have the potential to provide a significant improvement over the polarizations in probing the anomalous couplings.

    hep-phhep-exNPB(2022)·47 citations
12. 12*

    Time-reversal asymmetries and angular distributions in ${\Lambda }_b\to \Lambda V$

    Chao-Qiang Geng🇨🇳 · Chia-Wei Liu🇨🇳

    We study the spin correlations to probe time-reversal~(T) asymmetries in the decays of ${\Lambda }_b\to \Lambda V(V=\varphi ,{\rho }^0,\omega ,K^{\ast 0})$. The eigenstates of the T-odd operators are obtained along with definite angular momenta. We obtain the T-odd spin correlations from the complex phases among the helicity amplitudes. We give the angular distributions of ${\Lambda }_b\to \Lambda (\to p{\pi }^{-})V(\to P{P}^{\prime })$ and show the corresponding spin correlations, where $P^{(\prime )}$ are the pseudoscalar mesons. Due to the helicity conservation of the $s$ quark in $\Lambda$, we deduce that the polarization asymmetries of $\Lambda$ are close to $-1$. Since the decay of ${\Lambda }_b\to \Lambda \varphi$ in the standard model~(SM) is dictated by the single weak phase from the product of CKM elements, $V_{tb}{V}_{ts}^{\ast }$, the true T and CP asymmetries are suppressed, providing a clean background to test the SM and search for new physics. In the factorization approach, as the helicity amplitudes in the SM share the same complex phase, T-violating effects are absent. Nonetheless, the experimental branching ratio of $Br({\Lambda }_b\to \Lambda \varphi )=(5.18\pm 1.29)\times 10^{-6}$ suggests that the nonfactorizable effects or some new physics play an important role. By parametrizing the nonfactorizable contributions with the effective color number, we calculate the branching ratios and direct CP asymmetries. We also explore the possible T-violating effects from new physics.

    hep-phhep-exJHEP(2021)·19 citations
13. 13*

    Low-energy probes of sterile neutrino transition magnetic moments

    O. G. Miranda🇲🇽 · D. K. Papoulias🇬🇷 · O. Sanders🇲🇽 · M. Tórtola🇪🇸 · J. W. F. Valle🇪🇸

    Sterile neutrinos with keV-MeV masses and non-zero transition magnetic moments can be probed through low-energy nuclear or electron recoil measurements. Here we determine the sensitivities of current and future searches, showing how they can probe a previously unexplored parameter region. Future coherent elastic neutrino-nucleus scattering (CE$\nu$NS) or elastic neutrino-electron scattering (E$\nu$ES) experiments using a monochromatic ${}^{51}$Cr source can fully probe the region indicated by the recent XENON1T excess.

    hep-phJHEP(2021)·63 citations
14. 14*

    Collinear approach for top quark production at ep colliders

    G.R.Boroun🇮🇷

    An approximately analysis study of the collinear approach for $t\overline{t}$ production at the Future Circular Collider hadron-electron (FCC-he) and the Large Hadron electron Collider (LHeC) is performed. To study heavy quark production processes, the collinear generalized double asymptotic scaling (DAS) approach in a wide rang of $Q^2$ is used. The reduced cross sections for top quark pair production at the FCC-he (for $Q^2\ge m_t^2$) and LHeC (for $Q^2\le m_t^2$) center-of-mass energies at the high inelasticity are derived. These results may be considering for both the future collider experiments at center-of-mass energy frontier and the improvement of the phenomenological models on kinematics of low values of the Bjorken variable $x$. The evolution of the gluon density for heavy-quark production in DIS is obtained at low $x$ to include effects of heavy-quark masses. A nonlinear modification of these results shown that the nonlinear corrections, with respect to the top quark mass, are very small for $Q^2\propto m_t^2$.

    hep-phEur.Phys.J.Plus(2023)·5 citations
15. 15*

    Testing left-right symmetry with an inverse seesaw mechanism at the LHC

    Mathew Thomas Arun🇮🇳 · Tanumoy Mandal🇮🇳 · Subhadip Mitra🇮🇳 · Ananya Mukherjee🇮🇳 · Lakshmi Priya🇮🇳 · Adithya Sampath🇮🇳

    In the left-right symmetric models, a heavy charged gauge boson $W^{\prime }$ can decay to a lepton and a right-handed neutrino (RHN). If the neutrino masses are generated through the standard type-I seesaw mechanism, the Yukawa couplings controlling two-body decays of the RHN become very small. As a result, the RHN decays to another lepton and a pair of jets via an off-shell $W^{\prime }$. This is the basis of the Keung-Senjanović (KS) process, which was originally proposed as a probe of lepton number violation at the LHC. However, if a different mechanism like the inverse seesaw generates the neutrino masses, a TeV-scale RHN can have large Yukawa couplings and hence dominantly decay to a lepton and a $W$ boson, leading to a kinematically different process from the KS one. We investigate the prospect of this unexplored process as a probe of the inverse seesaw mechanism in the left-right symmetric models at the High Luminosity LHC (HL-LHC). Our signal arises from the Drell-Yan production of a $W^{\prime }$ and leads to two high-$p_T$ same-flavour-opposite-sign leptons and a boosted $W$-like fatjet in the final state. We find that a sequential $W^{\prime }$ with mass up to $\sim 6$~TeV along with a TeV-scale RHN can be discovered at the HL-LHC.

    hep-phhep-exPRD(2022)·17 citations
16. 16*

    Properties of neutral mesons in a hot and magnetized quark matter: size-dependent effects

    Luciano M. Abreu🇧🇷 · Emerson B. S. Corrêa🇧🇷 · Elenilson S. Nery🇧🇷

    In this work we investigate the combined finite-size and thermomagnetic effects on the properties of neutral mesons in a hot medium, in the context of the Nambu--Jona-Lasinio model. In particular, by using the mean-field approximation and the Schwinger proper time method in a toroidal topology with antiperiodic conditions, we evaluate the chiral phase transition, the constituent quark mass and meson observables like the ${\pi }^0$ and $\sigma$ meson masses and pion decay constant under the change of the size, temperature, chemical potential and strength of external magnetic field. The results indicate that the observables are strongly affected by the conjoint effects of relevant variables, and the net result will depend on the balance of these competing phenomena.

    hep-phPRD(2022)·11 citations
17. 17*

    A comment on lepton mixing

    Dimitrios Metaxas🇬🇷

    Since right-handed neutrinos, if added to the Standard Model, have no gauge interactions, their kinetic terms can be mixed. I examine the related rotations of the gauge eigenstates in order to derive the propagators for the kinetic and mass terms, and I comment on the resulting lepton mixing, on the possibility of not having well-defined mass eigenstates, and on the modifications to weak contributions and observables (anomalous magnetic moment, muon decay, neutrino oscillations).

    hep-phhep-exEPL(2022)·0 citations
18. 18*

    Coloring mixed QCD/QED evolution

    Leif Gellersen🇸🇪 · Stefan Prestel🇸🇪 · Michael Spannowsky🇬🇧

    Parton showers are crucial components of high-energy physics calculations. Improving their modelling of QCD is an active research area since shower approximations are stumbling blocks for precision event generators. Naively, the interference between sub-dominant Standard-Model interactions and QCD can be of similar size to subleading QCD corrections. This article assesses the impact of QCD/QED interference effects in parton showers, by developing a sophisticated shower including QED, QCD at fixed color, and employing complete tree-level matrix element corrections for individual $N_C=3$ color configurations to embed interference. The resulting simulation indicates that QCD/QED interference effects are small for a simple test case and dwarfed by electro-weak resonance effects.

    hep-phSciPost Phys.(2022)·7 citations
19. 19*

    On the measurement of the muon anomalous magnetic moment

    Ara Ioannisian🇦🇲

    The ideas and formulas presented in the article will help to bring together the theoretical predictions for the anomalous magnetic moment of muon and the results of the "Muon g-2" experiment. In doing so, we are discussing the new effect exclusively within the Standard Model. In quantum physics a state with spin perpendicular to a magnetic field can be expressed as a superposition of energy eigenstates with spins parallel and antiparallel to the field: the resultant spin precession is due to the energy difference between the two eigenstates. If the state, like the muon, is unstable and can decay, it will have a natural energy spread. As a result the frequency of the spin precession can vary. For a constant magnetic field the measured spin precession velocity will be spread according to the Lorentzian distribution with width ${\left(\gamma \tau \right)}^{-1}$, for Lorentz gamma factor $\gamma =E/m$, and particle lifetime $\tau$. Although the true mean and variance of a Lorentzian distribution is undefined, the latter can be estimated by the maximum likelihood method to be $\frac{2}{N(\gamma \tau {)}^2}$, twice that of a normal distribution. Thus, the statistical error on the anomalous magnetic moment in reality should turn out to be wider than with ${\chi }^2$ analysis of the experiment.

    hep-phhep-ex0 citations
20. 20*

    Charged $B$ Mesogenesis

    Fatemeh Elahi🇩🇪 · Gilly Elor🇩🇪 · Robert McGehee🇺🇸

    We leverage the CP violation in charged $B$ meson decays to generate the observed baryon asymmetry and dark matter at $\mathcal{O}(10\text{ MeV})$ temperatures. We realize this in two scenarios: $B_c^{+}$ Mesogenesis and $B^{+}$ Mesogenesis. In the first, CP violating $B_c^{\pm }$ decays to $B^{\pm }$ mesons are followed by decays to dark and Standard Model baryons. In the second, CP violating $B^{\pm }$ decays to lighter charged mesons are accompanied by the latter's decays to dark and Standard Model leptons, which then scatter into the baryon asymmetry. $B_c^{+}$ Mesogenesis is actively being probed at Belle and LHCb, while $B^{+}$ Mesogenesis can be tested at colliders and sterile neutrino searches.

    hep-phastro-ph.COhep-exPRD(2022)·58 citations
21. 21*

    Threshold resummation of new partonic channels at next-to-leading power

    Melissa van Beekveld🇬🇧 · Leonardo Vernazza🇮🇹 · Chris D. White🇬🇧

    Collider observables involving heavy particles are subject to large logarithmic terms near threshold, which must be summed to all orders in perturbation theory to obtain sensible results. Relatively recently, this resummation has been extended to next-to-leading power in the threshold variable, using a variety of approaches. In this paper, we consider partonic channels that turn on only at next-to-leading power, and show that it is possible to resum leading logarithms using well-established diagrammatic techniques in Quantum Chromodynamics. We first consider deep inelastic scattering, where we reproduce the results of a recent study using an effective theory approach. Next, we consider the quark-gluon channel in both Drell-Yan and Higgs boson production, showing that an explicit all-order form for the leading logarithmic partonic cross section can be obtained. Our results agree with previous conjectures based on fixed-order results.

    hep-phhep-thJHEP(2021)·28 citations
22. 22*

    Friendship in the Axiverse: Late-time direct and astrophysical signatures of early-time nonlinear axion dynamics

    David Cyncynates🇺🇸 · Tudor Giurgica-Tiron🇺🇸 · Olivier Simon🇺🇸 · Jedidiah O. Thompson🇺🇸

    A generic low-energy prediction of string theory is the existence of a large collection of axions, commonly known as a string axiverse. Axions also have a natural cosmological production mechanism, vacuum misalignment, making them well-motivated dark matter (DM) candidates. Much work on axion production has considered the case of a single free axion, but in a realistic axiverse, string axions are expected to be distributed densely over many orders of magnitude in mass, and to interact with one another through their joint potential. In this paper, we show that non-linearities in this potential lead to a new type of resonant energy transfer between axions with nearby masses. This resonance generically transfers energy from axions with larger decay constants to those with smaller decay constants, and leads to a multitude of signatures. These include enhanced direct detection prospects for a resonant pair comprising even a small subcomponent of dark matter, and boosted small-scale structure if the pair is the majority of DM. Near-future iterations of experiments such as ADMX and DM Radio will be sensitive to this scenario, as will astrophysical probes of DM substructure.

    hep-phastro-ph.COhep-thnlin.PSPRD(2022)·57 citations
23. 23*

    Extension of the Goldstone and the Englert-Brout-Higgs mechanisms to non-Hermitian theories

    Philip D. Mannheim🇺🇸

    We discuss the extension of the Goldstone and Englert-Brout-Higgs mechanisms to non-Hermitian Hamiltonians that possess an antilinear PT symmetry. We study a model due to Alexandre, Ellis, Millington and Seynaeve and show that for the spontaneous breakdown of a continuous global symmetry we obtain a massless Goldstone boson in all three of the antilinear symmetry realizations: eigenvalues real, eigenvalues in complex conjugate pairs, and eigenvalues real but eigenvectors incomplete. In this last case we show that it is possible for the Goldstone boson mode to be a zero-norm state. For the breakdown of a continuous local symmetry the gauge boson acquires a non-zero mass by the Englert-Brout-Higgs mechanism in all realizations of the antilinear symmetry, except the one where the Goldstone boson itself has zero norm, in which case, and despite the fact that the continuous local symmetry has been spontaneously broken, the gauge boson remains massless.

    ↳ hep-thhep-ph9 citations
24. 24*

    General Tensor Structure for Inclusive and Semi-inclusive Electron Scattering from Polarized Spin 1/2 Targets

    T. W. Donnelly🇺🇸 · Sabine Jeschonnek🇺🇸 · J. W. Van Orden🇺🇸

    The general structure of semi-inclusive polarized electron scattering from polarized spin-1/2 targets is developed for use at all energy scales, from modest-energy nuclear physics applications to use in very high energy particle physics. The leptonic and hadronic tensors that enter in the formalism are constructed in a general covariant way in terms of kinematic factors that are frame dependent but model independent and invariant response functions which contain all of the model-dependent dynamics. In the process of developing the general problem the relationships to the conventional responses expressed in terms of the helicity components of the exchanged virtual photon are presented. For semi-inclusive electron scattering with polarized electrons and polarized spin-1/2 targets one finds that 18 invariant response functions are required, each depending on four Lorentz scalar invariants. Additionally it is shown how the semi-inclusive cross sections are related via integrations over the momentum of the selected coincidence particle and sums over open channels.

    ↳ nucl-thhep-phAnnals of Physics, Volume 448, January 20…·5 citations
25. 25*

    Non-minimal coupled warm inflation with quantum-corrected self-interacting inflaton potential

    Daris Samart (Khon Kaen U.)🇹🇭 · Patinya Ma-adlerd (Khon Kaen U.)🇹🇭 · Peeravit Koad (Walailak U.)🇹🇭 · Phongpichit Channuie (Walailak U.)🇹🇭

    In this work, we investigate the non-minimally coupled scenario in the context of warm inflation with quantum-corrected self-interacting potential. We transform the potential in the Jordan frame to the Einstein frame and consider a dissipation parameter of the form $\Gamma =C_{T}T$ with $C_T$ being a coupling parameter. We focus on the strong regime of which the interaction between inflaton and radiation fluid has been taken into account. We compute inflationary observables and constrain the parameters of our model using current Planck 2018 data. With the sizeable number of {\it e}-folds and proper choices of parameters, we discover that allowed values of $C_T$ lie in the range $0.014\lesssim C_T\lesssim 0.020$ in which the predictions are in good agreement with the latest Planck 2018 results at the $2\sigma$ confident level.

    ↳ astro-ph.COgr-qchep-phEPJC(2022)·9 citations
26. 26*

    The current recorded signals of ultrahigh-energy $\gamma$-rays may come from EeVatrons in the galaxy

    Wei Zhu🇨🇳 · Peng Liu🇨🇳 · Zhiyi Cui🇨🇳 · Jianhong Ruan🇨🇳

    A hard $\gamma$-ray spectrum of supernova remnant G106.3+2.7 can be explained by using the hadronic model with the gluon condensation effect. This implies that not only PeVatrons but also EeVatrons generally exist in the universe including our galaxy, and they can accelerate protons to beyond "ankle" ($10^{19}eV$). Although these proton beams are very weak in the galaxy and cannot be observed individually on the earth, the gluon condensation effect may greatly enhance the proton-proton cross section, which can compensate for the weak proton flux and produce the observed $\gamma$-rays. We also show that the gluon condensation effect in proton provides an efficient conversion mechanism for kinetic energy into $\gamma$-rays in the universe.

    ↳ astro-ph.HEhep-ph0 citations
27. 27*

    First-principle calculation of ${\eta }_c\to 2\gamma$ decay width from lattice QCD

    Yu Meng🇨🇳 · Xu Feng🇨🇳 · Chuan Liu🇨🇳 · Teng Wang🇨🇳 · Zuoheng Zou🇨🇳

    We perform a lattice QCD calculation of the ${\eta }_c\to 2\gamma$ decay width using a model-independent method that requires no momentum extrapolation of the off-shell form factors. This method also provides a straightforward and simple way to examine the finite-volume effects. The calculation is accomplished using $N_f=2$ twisted mass fermion ensembles. The statistically significant excited-state effects are observed and eliminated using a multi-state fit.The impact of fine-tuning the charm quark mass is also examined and confirmed to be well-controlled. Finally, using three lattice spacings for the continuum extrapolation, we obtain the decay width ${\Gamma }_{{\eta }_c\gamma \gamma }=6.67(16{)}_{\mathrm{stat}}(6{)}_{\mathrm{syst}}$ keV, which differs significantly from the Particle Data Group's reported value of ${\Gamma }_{{\eta }_c\gamma \gamma }=5.4(4)$ keV (2.9~$\sigma$ tension). We provide insight into the comparison between our findings, previous theoretical predictions, and experimental measurements.

    ↳ hep-lathep-exhep-phSci.Bull.(2023)·32 citations
28. 28*

    Spin-1 fields and RG flows in 4 dimensions

    Daniel Nogradi🇭🇺

    The most general local, classically scale invariant, perturbatively renormalizable, globally $SU(N)$ invariant Lagrangian is constructed for spin-1 fields in 4 dimensions. The total number of independent couplings is 7 and the 1-loop $\beta$-functions are computed in the MSbar scheme. A number of asymptotically free RG flows are identified corresponding to non-trivial QFTs. None of these are gauge theories. The details of the large-$N$ limit are also worked out and it is shown that the RG phase space is qualitatively similar for all $N>5$ including the $N\to \infty$ limit.

    ↳ hep-lathep-phPoS(2022)·0 citations
29. 29*

    Comment on "More Axions from Strings''

    Mark Hindmarsh🇫🇮 · Joanes Lizarraga🇪🇸 · Asier Lopez-Eiguren🇺🇸 · Jon Urrestilla🇪🇸

    We comment on a claim that axion strings show a long-term logarithmic increase in the number of Hubble lengths per Hubble volume [arXiv:2007.04990], thereby violating the standard "scaling" expectation of an O(1) constant. We demonstrate that the string density data presented in [arXiv:2007.04990] are consistent with standard scaling, at a string density consistent with that obtained by us [arXiv:1908.03522, arXiv:2102.07723] and other groups. A transient slow growth in Hubble lengths per Hubble volume towards its constant scaling value is explained by standard network modelling [arXiv:2102.07723].

    ↳ astro-ph.COhep-ph28 citations
30. 30*

    Radion dynamics in the Multibrane Randall-Sundrum Model

    Haiying Cai🇰🇷

    The radion equilibrium in the Randall-Sundrum (RS) model is guaranteed by the back-reaction of a bulk scalar field. In this paper we study an extended scenario, where an intermediate brane exists in addition to the two branes at the fixed points, due to the discontinuity of bulk cosmology constants in two spatial regions. We conducted a complete analysis of the linearized Einstein's equations after applying the Goldberger-Wise mechanism. Our result elucidates that in the presence of nonfixed point branes under the rigid assumption, a unique radion field is conjectured as legitimate in the RS metric perturbation. The cosmological expansion in this setup is briefly discussed.

    ↳ hep-thhep-phPRD(2022)·15 citations
31. 31*

    Circuit Complexity in ${\mathcal{Z}}_2$ $\mathcal{EEF}\mathcal{T}$

    Kiran Adhikari🇩🇪 · Sayantan Choudhury🇮🇳 · Sourabh Kumar🇨🇦 · Saptarshi Mandal🇮🇳 · Nilesh Pandey🇮🇳 · Abhishek Roy🇮🇳 · Soumya Sarkar🇮🇳 · Partha Sarker🇧🇩 · Saadat Salman Shariff🇮🇳

    Motivated by recent studies of circuit complexity in weakly interacting scalar field theory, we explore the computation of circuit complexity in ${\mathcal{Z}}_2$ Even Effective Field Theories (${\mathcal{Z}}_2$ EEFTs). We consider a massive free field theory with higher-order Wilsonian operators such as ${\varphi }^4$, ${\varphi }^6$ and ${\varphi }^8.$ To facilitate our computation we regularize the theory by putting it on a lattice. First, we consider a simple case of two oscillators and later generalize the results to $N$ oscillators. The study has been carried out for nearly Gaussian states. In our computation, the reference state is an approximately Gaussian unentangled state, and the corresponding target state, calculated from our theory, is an approximately Gaussian entangled state. We compute the complexity using the geometric approach developed by Nielsen, parameterizing the path ordered unitary transformation and minimizing the geodesic in the space of unitaries. The contribution of higher-order operators, to the circuit complexity, in our theory has been discussed. We also explore the dependency of complexity with other parameters in our theory for various cases.

    ↳ hep-thcond-mat.stat-mechgr-qchep-ph+1Symmetry(2023)·14 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.