Fri·May 5, 2023Friday·May 5, 2023

1. 01*

   Scrutinizing the Light Scalar Quarkonia from LSR at Higher Orders

   R. Albuquerque (FAT, UERJ, Rio de Janeiro, BR)🇧🇷 · S. Narison (LUPM, CNRS-IN2P3, Montpellier, FR and iHEPMAD, Univ. Antananarivo, MG)🇫🇷 · D. Rabetiarivony (iHEPMAD, Univ. Antananarivo, MG)🇲🇬

   We scrutinize, improve some determinations of the masses and couplings of light scalar quarkonia ($\bar{q}q$ and four-quark states) and present new results for the ${\pi }^{+}{\pi }^{-},K^{+}{K}^{-},\dots$ molecules using QCD Laplace Sum Rule (LSR) truncated at the $D=6$ dimension vacuum condensates. We pay a special attention on the higher order perturbative (PT) corrections up to the (estimated) $\mathcal{O}({\alpha }_s^5)$ which improve the quality of the analysis. We request that the optimal results obey the rigorous constraint: {\it Resonance $\ge$ QCD continuum contributions ($R_{P/C}\ge 1$)} in the LSR which excludes a Breit-Wigner / on-shell (not to be confused with a complex pole) scalar meson mass around (500-600) MeV obtained for values [$t_c\le (1\sim 1.5)$ GeV${}^2$] of the QCD continuum threshold. Mass-splittings due to $SU3$ breakings are small. We discuss the different assignements of the observed scalar mesons below 2 GeV in the Conclusions where the $I=0$ states are compared with the scalar gluonia. The results are compiled in Table 3 to 6.

   hep-phhep-exhep-latNPA(2023)·19 citations
2. 02*

   $\Lambda$ polarization from vortex ring as medium response for jet thermalization

   Vitor Hugo Ribeiro🇧🇷 · David Dobrigkeit Chinellato🇧🇷 · Michael Annan Lisa🇺🇸 · Willian Matioli Serenone🇧🇷 · Chun Shen🇺🇸 · Jun Takahashi🇧🇷 · Giorgio Torrieri🇧🇷

   We performed a systematic study on the formation of vorticity rings as the process for jet thermalization in the medium created in high-energy nuclear collisions. In this work, we expanded our previous analysis to a more realistic framework by considering non-central events and fluctuations in the initial condition. We simulate the formation and evolution of the flow vortex structure in a relativistic viscous hydrodynamic model and study the sensitivity of the proposed ``ring observable'' (${\mathcal{R}}_{\Lambda }^t$) that can be measured experimentally through the polarization of $\Lambda$ hyperons. We show that this observable is robust with respect to fluctuating initial conditions to capture the jet-induce vortex flow signal and further study its dependence on different model parameters, such as the jet's velocity, position, the fluid's shear viscosity, and the collision's centrality. The proposed observable is associated to the formation of vorticity in a quark-gluon plasma, showing that the measurement of particle polarization can be a powerful tool to probe different properties of jet-medium interactions and to understand better the polarization induced by the transverse and longitudinal expansions of the medium.

   hep-phPRC(2024)·6 citations
3. 03*

   Form factors of the nucleon by using the t dependence of parton distribution functions

   Hossein Vaziri🇮🇷 · Mohammad Reza Shojaei🇮🇷

   This paper calculates the elastic form factors for nucleons based on generalized parton distributions using an extended new ansatz introduced in http://dx.doi.org/10.1103/PhysRevC.105.025202 (Phys. Rev. C 105, no.2, 025202 (2022)). Different parton distribution functions (PDFs) are considered, and modifications are made to the free parameters of the new ansatz. The obtained results are systematically compared among the combinations of different PDFs and ansatzes for high ranges of momentum transfer, with $-t<35Ge{V}^{-2}$. The minimum suitable parameters are used to parametrize the model. After obtaining the form factors, we proceed to compute the electric radius and the transversely unpolarized densities for the nucleon. In addition, we derive the parton distribution functions (PDFs) that depend on the impact parameter. Finally, we analyze the results by comparing them with the findings from other research and experimental data.

   hep-phPRC(2023)·8 citations
4. 04*

   Searching for the baryon-to-meson transition region with the MPD at NICA

   Alejandro Ayala🇲🇽 · Wolfgang Bietenholz🇲🇽 · Eleazar Cuautle🇲🇽 · Rodrigo García Formentí🇲🇽 · Rodrigo Guzmán🇲🇽

   In heavy-ion reactions, statistical models predict a rapid change in the baryon-to-meson ratio as a function of the collision energy. This change occurs when the hadronic medium transits from a baryon- to a meson-dominated gas. The transition is expected to take place at a temperature around 140 MeV and a baryon chemical potential around 420 MeV, corresponding to a center-of-mass collision energy of $\sqrt{s_{NN}}\simeq 8.2$ GeV. The energy range of the MPD experiment will be suitable for the exploration of this transition region. We present preliminary results of feasibility studies for the measurement of the transverse momentum spectra for mesons and baryons, using Monte Carlo data samples, in order to study the crossing point between these transverse momenta, as a function of the centrality and collision energy.

   hep-phnucl-thPhys.Atom.Nucl.(2023)·5 citations
5. 05*

   Placing of the recently observed bottom strange state $B_{sJ}(6063)$ and $B_{sJ}(6114)$ in bottom spectra

   Ritu Garg🇮🇳 · Pallavi Gupta🇮🇳 · A. Upadhyay🇮🇳

   We have employed HQET to give the spin-parity quantum numbers for recently observed bottom strange states $B_{sJ}(6063)$ and $B_{sJ}(6114)$ by LHCb collaborations. By exploring flavour independent parameters ${\Delta }_F^{(c)}={\Delta }_F^{(b)}$ and ${\lambda }_F^{(c)}={\lambda }_F^{(b)}$, we calculated masses of experimentally missing bottom strange meson states $2S,1P,1D$. We have also analyzed these bottom strange masses by taking $1/m_Q$ corrections which lead modifications of parameter terms as ${\Delta }_F^{(b)}={\Delta }_F^{(c)}+\delta {\Delta }_F$ and ${\lambda }_F^{(b)}={\lambda }_F^{(c)}\delta {\lambda }_F$. Further, we have analyzed their two-body decays, couplings, and branching ratios via the emission of light pseudoscalar mesons. Based on predicted masses and decay widths, we tentatively identified the states $B_{sJ}(6063)$ as $2^3{S}_1$ and $B_{sJ}(6114)$ as $1^3{D}_1$. Our predictions provide crucial information for future experimental studies.

   hep-phPTEP(2023)·2 citations
6. 06*

   Gravitational freeze-in dark matter from Higgs Preheating

   Ruopeng Zhang🇨🇳 · Zixuan Xu🇨🇳 · Sibo Zheng🇨🇳

   Gravitational freeze-in is a mechanism to explain the observed dark matter relic density if dark matter neither couples to inflation nor to standard model sector. In this work, we study gravitational freeze-in dark matter production during Higgs preheating based on non-perturbative resonance. Using reliable lattice method to handle this non-perturbative process, we show that tachyonic resonance is prohibited by strong back reaction due to Higgs self interaction needed to keep the positivity of potential during preheating, and parameter resonance is viable by tuning the Higgs self-interaction coupling to be small enough in ultraviolet energy scale. We then derive the dark matter relic density under the context of Higgs preheating, and uncover a new dark matter parameter space with dark matter mass larger than inflaton mass, which arises from out-of-equilium Higgs annihilation. Finally, we briefly remark the open question of testing gravitational dark matter.

   hep-phastro-ph.COJCAP(2023)·20 citations
7. 07*

   Properties of N, $\Delta$ Baryons with Screened Potential

   C. Menapara🇮🇳 · A. K. Rai🇮🇳

   N and $\Delta$ baryons hold an important place towards understanding the quark dynamics inside hadrons. The hypercentral Constituent Quark Model (hCQM) has been employed in various studies ranging from light to heavy hadrons. In the present article, screened potential has been used to study light baryon resonances. The Regge trajectories have been plotted alongwith the details of slopes and intercepts. The strong decay widths to pion have been calculated for some channels using the present masses.

   hep-phFew Body Syst.(2024)·3 citations
8. 08*

   Probing Dark Matter via Effective Field Theory Approach

   Ayşe Elçiboğa Kuday🇹🇷 · Ferhat Özok🇹🇷 · Erdinç Ulaş Saka🇹🇷

   We analyse dark matter in most general form of effective field theory approach. To examine the interactions between weakly interacting massive particles(WIMPs) and Standard Model (SM) particles, we use the six-dimensional EFT mediated by new physics scale $\Lambda$ at tree level. After implementing a new effective field theory model in FeynRules \cite{Feynrules} We investigate the theory and constrain the theory by using relic density generated by MadDM\cite{Maddm} tool of MadGraph5\_aMC@NLO \cite{mg5}.

   hep-phInt.J.Geom.Meth.Mod.Phys.(2020)·2 citations
9. 09*

   Exotic spin-dependent interactions through unparticle exchange

   L. Y. Wu🇨🇳 · K. Y. Zhang🇨🇳 · H. Yan🇨🇳

   The potential discovery of unparticles could have far-reaching implications for particle physics and cosmology. For over a decade, high-energy physicists have extensively studied the effects of unparticles. In this study, we derive six types of nonrelativistic potentials between fermions induced by unparticle exchange in coordinate space. We consider all possible combinations of scalar, pseudo-scalar, vector, and axial-vector couplings to explore the full range of possibilities. Previous studies have only examined scalar-scalar (SS), pseudoscalar-pseudoscalar (PP), vector-vector (VV), and axial-axial-vector (AA) type interactions, which are all parity even. We propose SP and VA interactions to extend our understanding of unparticle physics, noting that parity conservation is not always guaranteed in modern physics. We explore the possibilities of detecting unparticles through the long-range interactions they may mediate with ordinary matter. Dedicated experiments using precision measurement methods can be employed to search for such interactions. We discuss the properties of these potentials and estimate constraints on several coupling constants based on existing experimental data. Our findings indicate that the coupling between vector unparticles and fermions is constrained by up to 9 orders of magnitude more tightly than the previous limits.

   hep-phnucl-thJHEP(2024)·4 citations
10. 10*

    Axial-vector charges of the spin ${\frac{1}{2}}^{+}$ and spin ${\frac{3}{2}}^{+}$ light and charmed baryons in the SU(4) chiral quark constituent model

    Harleen Dahiya🇮🇳 · Suneel Dutt🇮🇳 · Arvind Kumar🇮🇳 · Monika Randhawa🇮🇳

    Following the first clear evidence of the presence of intrinsic charm contribution in the proton, the axial-vector charges of the light and charmed baryons are investigated in the framework of $SU(4)$ chiral constituent quark model after including the explicit contributions from the $u\bar{u}$, $d\bar{d}$, $s\bar{s}$ and $c\bar{c}$ fluctuations. The axial-vector charges having physical significance correspond to the generators of the $SU(4)$ group with flavor singlet ${\lambda }^0$, flavor isovector ${\lambda }^3$, flavor hypercharge ${\lambda }^8$ and flavor charmed ${\lambda }^{15}$ combinations of axial-vector current at zero momentum transfer. In contemplation to further understand the $Q^2$ dependence of these charges, we have used the conventionally established dipole form of parametrization. The baryons considered here are the spin ${\frac{1}{2}}^{+}$ and spin ${\frac{3}{2}}^{+}$ multiplets decomposed further depending on the charm content of baryons.

    hep-phEur.Phys.J.Plus(2023)·9 citations
11. 11*

    Study of nuclear corrections on the charged hadron fragmentation functions in a Neural Network global QCD analysis

    Maryam Soleymaninia🇮🇷 · Hadi Hashamipour🇮🇷 · Hamzeh Khanpour🇮🇷 · Samira Shoeib🇮🇷 · Alireza Mohamaditabar🇮🇷

    In this work, we present a new global QCD analyses, referred to as PKHFF.23, for charged pion, kaon, and unidentified light hadrons. We utilize a Neural Network to fit the high-energy lepton-lepton and lepton-hadron scattering data, enabling us to determine parton-to-hadron fragmentation functions (FFs) at next-to-leading-order (NLO) accuracy. The analyses include all available single-inclusive $e^{+}{e}^{-}$ annihilation (SIA) and semi-inclusive deep-inelastic scattering (SIDIS) data from the COMPASS Collaboration for charged pions, kaons, and unidentified light hadrons. Taking into account the most recent nuclear parton distribution functions (nuclear PDFs) available in the literature, we evaluate the effect of nuclear corrections on the determination of light hadrons FFs. The Neural Network parametrization, enriched with the Monte Carlo methodology for uncertainty estimations, is employed for all sources of experimental uncertainties and the proton PDFs. Our results indicate that incorporating nuclear corrections has a marginal impact on the central values of FFs and their corresponding uncertainty bands. The inclusion of such corrections does not significantly affect the fit quality of the data as well. The study suggests that while nuclear corrections are a consideration, their impact in such QCD analysis is limited.

    hep-phEur.Phys.J.Plus(2024)·2 citations
12. 12*

    Generalized parton distributions of $\Delta$ resonance in a diquark spectator approach

    Dongyan Fu🇨🇳 · Bao-Dong Sun🇨🇳 · Yubing Dong🇨🇳

    The generalized parton distributions (GPDs) for the spin-3/2 ${\Delta }^{+}$ resonance are studied numerically by using a diquark spectator approach. Our results show that symmetric constraints from time reversal on GPDs are satisfied. The axial vector form factors of the system are also provided and compared with the lattice QCD calculation. Furthermore, the structure functions are obtained from GPDs in the forward limit. The evolution of structure functions to the scales up to 4 GeV are carried out as predictions for the possible lattice QCD calculations.

    hep-phPRD(2023)·9 citations
13. 13*

    Radiative corrections to stop-antistop annihilation

    Luca Paolo Wiggering🇩🇪

    We compute the full $\mathcal{O}({\alpha }_s)$ corrections to stop-antistop annihilation into two gluons and a light quark-antiquark pair within the framework of the Minimal Supersymmetric Standard Model (MSSM), including the non-perturbative Sommerfeld enhancement effect. Numerical results for the total annihilation cross section are shown and the effect on the neutralino relic density is discussed for an example scenario in the phenomenological MSSM.

    hep-ph0 citations
14. 14*

    Bound state solutions of the Schrödinger equation for dibaryons via asymptotic iteration method

    Nazanin Shiri🇮🇷 · Narges Tazimi🇮🇷 · Majid Monemzadeh🇮🇷

    Conventionally, hexaquarks are claimed to be exotic particles, most of which have not yet been experimentally detected. In this work, we study the mass spectra of exotic hadrons known as hexaquarks in the form of dibaryons. We investigate the hexaquark states with the twobody configuration in more detail. Starting from the analytical solution of the radial Schrödinger equation for the Hulthén potential in the framework of the asymptotic iteration method (AIM), we obtain the binding energy and mass spectrum of charm and bottom hexaquarks for different spin states. We strongly recommend searching experimentally for double charm and bottom dibaryons in the future.

    hep-phhep-thnucl-th5 citations
15. 15*

    Analysis of three-body charmless $B$-meson decays under the factorization-assisted topological-amplitude approach

    Si-Hong Zhou🇨🇳 · Xin-Xia Hai🇨🇳 · Run-Hui Li🇨🇳 · Cai-Dian Lu🇨🇳

    We analyze quasi-two-body charmless $B$ decays $B_{(s)}\to P_{1}V\to P_1{P}_2{P}_3$ with $V$ representing a vector resonant, and $P_{1,2,3}$ as a light pseudo-scalar meson, pion, kaon or ${\eta }^{(\prime )}$. The intermediate processes $B_{(s)}\to P_{1}V$ are calculated in the factorization-assisted topological-amplitude approach and the vector resonant effects are described by the Breit-Wigner propagator, which successively decay to $P_1{P}_2$ via strong interaction. Taking into account of all vector resonances in ground state, $\rho ,K^{\ast },\omega ,\varphi$, we present the related branching fractions, and calculate the virtual effects for $B_{(s)}\to \pi ,K(\rho ,\omega \to )KK$. We also predict direct $CP$ asymmetries of three body B decay modes with $\rho ,K^{\ast }$ resonances as intermediate states. Our predicted branching fractions of decay modes dominated by the color-favored tree diagram or the color-favored penguin diagram are consistent with the perturbative QCD approach's predictions as well as QCD factorization approach. While for those nonperturbative contribution dominated decay modes, the branching ratios in this work are in better agreement with current experimental data than the PQCD predictions and the QCD factorization results due to their shortage of the nonperturbative contributions or $1/m_b$ power corrections. Many of the decays channels, especially for direct $CP$ asymmetries, are waiting for the future experiments.

    hep-phPRD(2023)·12 citations
16. 16*

    Role of $f_0(980)$ and $a_0(980)$ in the $B^{-}\to {\pi }^{-}{K}^{+}{K}^{-}$ and $B^{-}\to {\pi }^{-}{K}^0{\bar{K}}^0$ reactions

    Luciano M. Abreu🇧🇷 · Natsumi Ikeno🇯🇵 · Eulogio Oset🇪🇸

    In this work we study the role of the $f_0(980)$ and $a_0(980)$ resonances in the low $K^{+}{K}^{-}$ and $K^0{\bar{K}}^0$ invariant-mass region of the $B^{-}\to {\pi }^{-}{K}^{+}{K}^{-}$ and $B^{-}\to {\pi }^{-}{K}^0{\bar{K}}^0$ reactions. The amplitudes are calculated by using the chiral unitary $\mathrm{SU}(3)$ formalism, in which these two resonances are dynamically generated from the unitary pseudocalar-pseudoscalar coupled-channel approach. The amplitudes are then used as input in the evaluation of the mass distributions with respect to the $K^{+}{K}^{-}$ and $K^0{\bar{K}}^0$ invariant-masses, where the contributions coming from the $I=0$ and $I=1$ components are explicitly assessed. Furthermore, the contribution of the $K^{\ast }(892{)}^0{K}^{-}$ production and its influence on the ${\pi }^{-}{K}^{+}$ and $K^{+}{K}^{-}$ systems are also evaluated, showing that there is no significant strength for small $K^{+}{K}^{-}$ invariant mass. Lastly, the final distributions of $M_{\mathrm{inv}}^2(K^{\pm }{K}^{\mp })$ for the $B^{\mp }\to {\pi }^{\mp }{K}^{\pm }{K}^{\mp }$ reactions are estimated and compared with the LHCb data. Our results indicate that the $I=0$ component tied to the $f_0(980)$ excitation generates the dominant contribution in the range of low $K^{+}{K}^{-}$ invariant-mass.

    hep-phPRD(2023)·4 citations
17. 17*

    Two-component WIMP $-$ FIMP dark matter

    Francesco Costa🇩🇪

    The document discusses a proposed extension to the Standard Model that aims to explain the presence of neutrino masses and the existence of dark matter. The model includes two potential candidates for dark matter, a vector WIMP and a fermion FIMP, and their combined presence accounts for the total amount of observed dark matter. This study examines the various ways in which dark matter could be produced within this model and explores the connections between the dark matter and neutrino sectors. It also examines various constraints from existing and future experiments. Additionally, the model includes a scalar field that can play a role in a first-order phase transition in the early universe, and the article looks at the potential for the production of gravitational waves as a result of this phase transition and their detectability. This study also assesses the possibility for this phase transition to be strong enough to drive the electroweak baryogenesis.

    hep-phPoS(2024)·0 citations
18. 18*

    Quarkonium spin alignment in a vortical medium

    Paulo Henrique De Moura🇧🇷 · Kayman J. Goncalves🇧🇷 · Giorgio Torrieri🇧🇷

    We use a potential model to investigate the phenomenology of quarkonium in a thermal rotating medium, where vorticity and spin density are not necessarily in equilibrium. We find that the quarkonium spin density matrix, as well as the binding energy and melting temperature, are sensitive to both the vorticity and the lack of equilibrium between vorticity and spin. This means that quarkonium spin alignment is a sensitive probe for vorticity and spin within the hydrodynamic phase. Information unequivocably pointing to spin-orbit non-equilibrium dynamics can be obtained from a combined study of quarkonium relative abundance and spin alignment, as well as experimentally obtainable off-diagonal density matrix elements.

    hep-phnucl-thPRD(2023)·20 citations
19. 19*

    anyH3: precise predictions for the trilinear Higgs coupling in the Standard Model and beyond

    Henning Bahl🇺🇸 · Johannes Braathen🇩🇪 · Martin Gabelmann🇩🇪 · Georg Weiglein🇩🇪

    The trilinear Higgs coupling ${\lambda }_{hhh}$ of the detected Higgs boson is an important probe for physics beyond the Standard Model. Correspondingly, improving the precision of the theoretical predictions for this coupling as well as the experimental constraints on it are among the main goals of particle physics in the near future. In this article, we present the public $\mathtt{Python}$ code $anyH3$, which provides precise theoretical predictions for ${\lambda }_{hhh}$. The program can easily be used for any renormalisable model, where for the input the $\mathtt{UFO}$ format is adopted. It allows including corrections up to the full one-loop level with arbitrary values of the external squared momenta and features a semi-automatic and highly flexible renormalisation procedure. The code is validated against known results in the literature. Moreover, we present new results for ${\lambda }_{hhh}$ in models which so far have not been investigated in the literature.

    hep-phEPJC(2023)·45 citations
20. 20*

    Dark matter from sterile-sterile neutrino mixing

    Pasquale Di Bari🇬🇧

    A solution to the problem of the origin of matter in the universe can be reasonably searched within extensions of the standard model that also explain neutrino masses and mixing. Models embedding the minimal seesaw mechanism can explain the observed matter-antimatter asymmetry of the universe via leptogenesis and dark matter via active-sterile neutrino mixing. In this case a keV lightest seesaw neutrino would play the role of warm dark matter particle. This traditional solution is now constrained by various cosmological observations. I will discuss the possibility that a much heavier but yet metastable (dark) right-handed neutrino with mass in the $1\mathrm{TeV}$--$1\mathrm{PeV}$ range can play the role of (cold) dark matter particle. The right abundance would be produced by the Higgs induced mixing with a seesaw right-handed neutrino (RHINO model), i.e., by sterile-sterile neutrino mixing. Such a mixing would necessarily require a further extension of the minimal seesaw mechanism and can be described by a dimension-five effective operator. The same mixing would also necessarily induce dark neutrino instability with lifetimes that can be much longer than the age of the universe and can escape current constraints from neutrino telescopes. On the other hand, a contribution to very high energy neutrino flux produced by dark neutrino decays could explain an anomalous excess at 100 TeV energies confirmed recently by the IceCube collaboration. I will also discuss a simple UV completion where the mediator is given by a massive fermion. Intriguingly, it comes out that the favoured scale of new physics for RHINO to satisfy the dark matter requirements coincides with the grand-unified scale: a RHINO miracle.

    hep-phPoS(2023)·0 citations
21. 21*

    Probing the onset of maximal entanglement inside the proton in diffractive DIS

    Martin Hentschinski🇲🇽 · Dmitri E. Kharzeev🇺🇸 · Krzysztof Kutak🇵🇱 · Zhoudunming Tu🇺🇸

    It has been proposed that at small Bjorken $x$, or equivalently at high energy, hadrons represent maximally entangled states of quarks and gluons. This conjecture is in accord with experimental data from the electron-proton collider HERA at the smallest accessible $x$. In this Letter, we propose to study the onset of the maximal entanglement inside the proton using Diffractive Deep Inelastic Scattering. It is shown that the data collected by the H1 Collaboration at HERA allows to probe the transition to the maximal entanglement regime. By relating the entanglement entropy to the entropy of final state hadrons, we find a good agreement with the H1 data using both the exact entropy formula as well as its asymptotic expansion which indicates the presence of a nearly maximally-entangled state. Finally, future opportunities at the Electron Ion Collider are discussed.

    hep-phhep-exnucl-exnucl-th+1PRL(2023)·52 citations
22. 22*

    Semi-inclusive $b\to s\bar{\ell }\ell$ transitions at high $q^2$

    Gino Isidori🇨🇭 · Zachary Polonsky🇨🇭 · Arianna Tinari🇨🇭

    We present an updated Standard Model (SM) estimate of the inclusive $b\to s\bar{\ell }\ell$ rate at high dilepton invariant mass ($q^2\ge 15{\mathrm{GeV}}^2$). We show that this estimate is in good agreement with the result obtained summing the SM predictions for the leading one-body modes ($K$ and $K^{\ast }$) and the subleading non-resonant $K\pi$ channel (for which we also present an updated estimate). On the contrary, the semi-inclusive sum based on data exhibits a deficit compared to the inclusive SM prediction in the muon modes. The statistical significance of this deficit does not exceed $2\sigma$, but is free from uncertainties on hadronic form factors, and fully compatible with the deficit observed at low-$q^2$ on the exclusive modes. The implications of these results in conjunction with other SM tests on $b\to s\bar{\mu }\mu$ modes are briefly discussed.

    hep-phPRD(2023)·33 citations
23. 23*

    Minimal model for the $W$-boson mass, $(g-2{)}_{\mu }$, $h\to {\mu }^{+}{\mu }^{-}$ and quark-mixing-matrix unitarity

    Andreas Crivellin🇨🇭 · Matthew Kirk🇪🇸 · Anil Thapa🇺🇸

    The $SU(2{)}_L$ triplet scalar with hypercharge $Y=0$ predicts a positive definite shift in the $W$ mass, w.r.t.~the Standard Model prediction, if it acquires a vacuum expectation value. As this new field cannot couple directly to SM fermions (on its own), it has no significant impact on other low-energy precision observables and is weakly constrained by collider searches. In fact, the multi-lepton anomalies at the LHC even point towards new scalars that decay dominantly to $W$ bosons, as the neutral component of the triplet naturally does. In this article, we show that with a minimal extension of the scalar triplet model by a heavy vector-like lepton, being either I) an $SU(2{)}_L$ doublet with $Y=-1/2$ or II) an $SU(2{)}_L$ triplet with $Y=-1$, couplings of the triplet to Standard Model leptons are possible. This minimal extension can then provide, in addition to the desired positive shift in the $W$ mass, a chirally enhanced contribution to $(g-2{)}_{\mu }$. In addition version I) and II) can improve on $Z\to {\mu }^{+}{\mu }^{-}$ and alleviate the tension in first-row CKM unitarity (known as the Cabibbo angle anomaly), respectively. Finally, both options, in general, predict sizable changes of $h\to {\mu }^{+}{\mu }^{-}$, i.e.,~much larger than most other $(g-2{)}_{\mu }$ explanations where only $O(\%)$ effects are expected, making this channel a smoking gun signature of our model.

    hep-phhep-exhep-latnucl-ex+1PRD(2023)·17 citations
24. 24*

    Dark Matter-Induced Stellar Oscillations

    Jeremy Sakstein🇺🇸 · Ippocratis D. Saltas🇨🇿

    It has been hypothesized that dark matter is comprised of ultra-light bosons whose collective phenomena can be described as a scalar field undergoing coherent oscillations. Examples include axion and fuzzy dark matter models. In this ultra-light dark matter scenario, the harmonic variation in the field's energy-momentum tensor sources an oscillating component of the gravitational potential that we show can resonantly-excite stellar oscillations. A mathematical framework for predicting the amplitude of these oscillations is developed, which reveals that ultra-light dark matter predominantly excites p-modes of degree $l=1$. An investigation of resonantly-excited solar oscillations is presented, from which we conclude that dark matter-induced oscillations of the Sun are likely undetectable. We discuss prospects for constraining ultra-light dark matter using other stellar objects.

    hep-phastro-ph.COastro-ph.SRgr-qcMNRAS(2023)·2 citations
25. 25*

    Dissipative Genesis of the Inflationary Universe

    Hiroki Matsui🇯🇵 · Alexandros Papageorgiou🇰🇷 · Fuminobu Takahashi🇯🇵 · Takahiro Terada🇰🇷

    We study an inflation model with a flat scalar potential supported by observations and find that slow-roll inflation can emerge after a quasi-cyclic phase of the Universe, where it undergoes repeated expansions and contractions for a finite time period. The initial conditions and the positive spatial curvature required for such nontrivial dynamics align with the quantum creation of the Universe. The key ingredients that trigger inflation are dissipative interactions of the inflaton, which are necessary to reheat the Universe after inflation and thus give us an observational handle on pre-inflationary physics. Our discovery implies that inflation occurs more robustly after the creation.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2024)·3 citations
26. 26*

    Dissipative Emergence of Inflation from Quasi-Cyclic Universe

    Hiroki Matsui🇯🇵 · Alexandros Papageorgiou🇰🇷 · Fuminobu Takahashi🇯🇵 · Takahiro Terada🇰🇷

    Inflationary models, especially those with plateau-type potentials, are consistent with the cosmological data, but inflation itself does not resolve the initial singularity. This singularity is resolved, for example, by the idea of the quantum creation of the Universe from nothing such as the tunneling and no-boundary proposals. The simplest one predicts a closed Universe. Motivated by these facts, we investigate the classical dynamics of a closed universe with a plateau-type potential. Depending on the initial inflaton field value, the universe can undergo a variety of events: an immediate big crunch, a bounce or cyclic phase, and inflation. Although the non-inflationary solutions may appear irrelevant to our Universe, they can be turned into single or multiple bounces followed by inflation, taking into account the interactions necessary for the reheating of the Universe after inflation. Thus, the dissipative mechanism in our setup explains both the graceful entry to and exit from inflation and gives us an indirect observational handle on the Universe just after creation. We also comment on the implications of these solutions for probabilistic interpretations of the wave function of the Universe.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2024)·5 citations
27. 27*

    Spontaneous Symmetry Breaking from an On-Shell Perspective

    Brad Bachu🇺🇸

    We show how the well known patterns of masses and interactions that arise from spontaneous symmetry breaking can be determined from an entirely on-shell perspective, that is, without reference to Lagrangians, gauge symmetries, or fields acquiring a vacuum expectation value. To do this, we review how consistent factorization of $2\to 2$ tree level scattering can lead to the familiar structures of Yang-Mills theories, and extend this to find structures of Yukawa theories. Considering only spins-$0$, $1/2$ and $1$ particles, we construct all the allowed on-shell UV amplitudes under a symmetry group $G$, and consider all the possible IR amplitudes. By demanding that on-shell IR amplitudes match onto on-shell UV amplitudes in the high energy limit, we reproduce the Higgs mechanism and generate masses for spins-$1/2$ and $1$, find that there is a subgroup $H\subseteq G$ in the IR, and other interesting relations. To highlight the results, we show the breaking pattern of the Standard Model $U(1{)}_{EM}\subset SU(2{)}_L\times U(1{)}_Y$, along with the generation of the masses and interactions of the particles.

    ↳ hep-thhep-phJHEP(2024)·13 citations
28. 28*

    The FLUKA cross sections for cosmic-ray leptons and uncertainties on current positron predictions

    Pedro De la Torre Luque🇸🇪 · Mario Nicola Mazziotta🇮🇹 · Francesco Loparco🇮🇹

    Cosmic-ray (CR) antiparticles have the potential to reveal signatures of unexpected astrophysical processes and even new physics beyond the Standard Model. Recent CR detectors have provided accurate measurements of the positron flux, revealing the so-called positron excess at high energies. However, the uncertainties related to the modelling of the local positron flux are still very high, significantly affecting our models of positron emission from pulsars and current dark matter searches. In this work, we report a new set of cross sections for positron and electron production derived from the {\tt FLUKA} code. We compare them with the most extended cross-section data-sets and show the impact of neglecting the positron production from heavy CRs. Then, we review the most significant sources of uncertainties in our current estimations of the secondary positron flux at Earth and examine for the first time the impact of considering the spiral arm structure of the Galaxy in these estimations. Finally, we provide state-of-the-art predictions of the local positron flux and discuss the limitations of our dark matter searches with positrons and difficulties to determine the contribution from pulsars to the positron flux at low energies.

    ↳ astro-ph.HEhep-phJCAP(2023)·13 citations
29. 29*

    Prospects for $B_c^{+}$ and $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ at FCC-ee

    Marco Fedele🇩🇪 · Clément Helsens🇩🇪 · Donal Hill🇨🇭 · Syuhei Iguro🇩🇪 · Markus Klute🇩🇪 · Xunwu Zuo🇩🇪

    The prospects are presented for precise measurements of the branching ratios of the purely leptonic $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ and $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ decays at the Future Circular Collider (FCC). This work is focused on the hadronic ${\tau }^{+}\to {\pi }^{+}{\pi }^{+}{\pi }^{-}{\bar{\nu }}_{\tau }$ decay in both $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ and $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ processes. Events are selected with two Boosted Decision Tree algorithms to optimise the separation between the two signal processes as well as the generic hadronic $Z$ decay backgrounds. The range of the expected precision for both signals are evaluated in different scenarios of non-ideal background modelling. This paper demonstrates, for the first time, that the $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ decay can be well separated from both $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ and generic $Z\to b\bar{b}$ processes in the FCC-ee collision environment and proposes the corresponding branching ratio measurement as a novel way to determine the CKM matrix element $|V_{ub}|$. The theoretical impacts of both $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ and $B_c^{+}\to {\tau }^{+}{\nu }_{\tau }$ measurements on New Physics cases are discussed for interpretations in the generic Two-Higgs-doublet model and leptoquark models.

    ↳ hep-exhep-phEPJC(2024)·35 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.