Thu·Dec 16, 2021Thursday·December 16, 2021

1. 01*

   Searching for axion-like particles with data scouting at ATLAS and CMS

   Simon Knapen🇨🇭 · Soubhik Kumar🇺🇸 · Diego Redigolo🇨🇭

   We investigate the physics case for a dedicated trigger-level analysis for very low mass diphoton resonances at ATLAS and CMS and introduce a new photon isolation criterion. This greatly increases the acceptance for light particles at the expense of a somewhat larger Standard Model background. We show how such an analysis would likely yield new experimental coverage for axion-like particles for masses below 15 GeV, bridging the gap with the region covered by flavor factories.

   hep-phPRD(2022)·21 citations
2. 02*

   Jet Charge: A new tool to probe the anomalous $Zb\bar{b}$ couplings at the EIC

   Hai Tao Li🇨🇳 · Bin Yan🇺🇸 · C.-P. Yuan🇺🇸

   We propose to utilize the average jet charge weighted single-spin asymmetry $A_e^{bQ}$ in the neutral current DIS scattering with one $b$-tagged jet produced at the EIC to probe the $Zb\bar{b}$ interactions. This novel observable is sensitive to the axial-vector component of the $Zb\bar{b}$ coupling and is complementary to the single-spin asymmetry measurement at the EIC and the $gg\to Zh$ cross section measurement at the HL-LHC in the determination of the $Zb\bar{b}$ couplings. We show that the apparent degeneracy of the $Zb\bar{b}$ couplings, implied by the LEP and SLC precision electroweak data, can be broken by the $A_e^{bQ}$ measurement at the EIC. With a large enough integrated luminosity collected at the EIC, the measurement of $A_e^{bQ}$ could also resolve the long-standing discrepancy of $A_{\mathrm{FB}}^b$ at the LEP, strongly dependent on the $b$-tagging efficiency.

   hep-phhep-exnucl-exnucl-thPLB(2022)·37 citations
3. 03*

   A Georgi-Machacek Interpretation of the Associate Production of a Neutral Scalar with Mass around 151 GeV

   François Richard🇫🇷

   Following an investigation of several indications for new physics from LHC data, a detailed exploration of the Georgi-Machacek (GM) model was elaborated in a previous publication. This framework is used here to interpret the findings of Crivellin et al., which were obtained by combining the 2 photon mass spectrum from ATLAS and CMS, adding extra conditions, the most efficient one being the presence of >90 GeV missing transverse energy. The claim is a ~5 s.d. excess at 151 GeV. The GM model naturally explains this as coming from the cascade A(400)->H(151)Z, where H(151) is an isosinglet predicted by GM and where the accompanying signal comes from the decay of a Z boson into neutrino pairs. Satisfying the constraints from LHC measurements of the ZWW channel, which can receive a large contribution from this cascade, suggests that H(151) could dominantly decay into two light CP-odd scalars, following an ATLAS indication for h(125) decaying into bbmumu. A spectacular occurrence of signals is predicted at an $e^{+}{e}^{-}$ collider operating up to 1 TeV, an energy sufficient to cover the whole scenario.

   hep-phhep-ex6 citations
4. 04*

   Form factors of $P\to T$ transition within the light-front quark models

   Lili Chen🇨🇳 · Yu-Wan Ren🇨🇳 · Li-Ting Wang🇨🇳 · Qin Chang🇨🇳

   In this paper, we calculate the vector, axial-vector and tensor form factors of $P\to T$ transition within the standard light-front~(SLF) and covariant light-front~(CLF) quark models~(QMs). The self-consistency and Lorentz covariance of CLF QM with two types of correspondence schemes are investigated. The zero-mode effects and the spurious $\omega$-dependent contributions to the form factors of $P\to T$ transition are analyzed. Employing a self-consistent CLF QM, we present our numerical predictions for the vector, axial-vector and tensor form factors of $c\to (q,s)$~($q=u,d$) induced $D\to (a_2,K_2^{\ast })$, $D_s\to (K_2^{\ast },f_2^{\prime })$, ${\eta }_c(1S)\to (D_2^{\ast },D_{s2}^{\ast })$, $B_c\to (B_2^{\ast },B_{s2}^{\ast })$ transitions and $b\to (q,s,c)$ induced $B\to (a_2,K_2^{\ast },D_2^{\ast })$, $B_s\to (K_2^{\ast },f_2^{\prime },D_{s2}^{\ast })$, $B_c\to (D_2^{\ast },D_{s2}^{\ast },{\chi }_{c2}(1P))$, ${\eta }_b(1S)\to (B_2^{\ast },B_{s2}^{\ast })$ transitions. Finally, in order to test the obtained form factors, the semileptonic $B\to {\bar{D}}_2^{\ast }(2460){\ell }^{+}{\nu }_{\ell }$~($\ell =e,\mu$) and ${\bar{D}}_2^{\ast }(2460){\tau }^{+}{\nu }_{\tau }$ decays are studied. It is expected that our results for the form factors of $P\to T$ transition can be applied further to the relevant phenomenological studies of meson decays.

   hep-phhep-exEPJC(2022)·21 citations
5. 05*

   The $Z_{cs}(3985{)}^{-}$ structure in a coupled-channels model

   Pablo G. Ortega🇪🇸 · David R. Entem🇪🇸 · Francisco Fernandez🇪🇸

   The discovery of the $Z_c(3900{)}^{\pm }$ and $Z_b(10610{)}^{\pm }$ structures in the heavy quarkonium spectrum showed the need to incorporate hadron structures beyond the naive $qqq$ and $q\bar{q}$ systems in quark models. The new charged structure called $Z_{cs}(3985{)}^{-}$, spotted in the $K^{+}$ recoil-mass spectrum close to the $D_s^{-}{D}^{\ast 0}/D_s^{\ast -}{D}^0$ threshold, is a new evidence in this line. In this work, we analyze the $Z_{cs}(3985{)}^{-}$ state, following the calculation of the $Z_c$ and $Z_b$ states using a chiral constituent quark model in a coupled-channels calculation, with all the parameters constrained from previous calculations. The pole structure of the S-matrix shows two virtual poles below the $D_s^{-}{D}^{\ast 0}$ and $D_s^{\ast -}{D}^{\ast 0}$ thresholds compatible with the $Z_{cs}(3985{)}^{\pm }$ and a new predicted $Z_{cs}(4110{)}^{\pm }$ structure, the SU(3) flavor partner of the $Z_c(4020{)}^{\pm }$. The $K^{+}$ recoil-mass spectrum is calculated in good agreement with LHCb and BESIII experimental data, with no fine tuning of the model parameters. Our results indicate that the $Z_{cs}(3985{)}^{\pm }$ and $Z_{cs}(4000{)}^{\pm }$ signals originate from the same virtual state.

   hep-ph3 citations
6. 06*

   Studying mass generation for gluons

   Gernot Eichmann🇵🇹 · Jan M. Pawlowski🇩🇪

   In covariant gauges, the gluonic mass gap in Yang-Mills theory manifests itself in the basic observation that the massless pole in the perturbative gluon propagator disappears in nonperturbative calculations, but the origin of this behavior is not yet fully understood. We summarize a recent study of the respective dynamics with Dyson-Schwinger equations in Landau-gauge Yang-Mills theory. We identify the parameter that distinguishes the massive Yang-Mills regime from the massless decoupling solutions, whose endpoint is the scaling solution. Similar to the PT-BFM scheme, we find evidence that mass generation in the transverse sector is triggered by longitudinal massless poles.

   hep-phhep-lathep-thSciPost Phys.Proc.(2022)·1 citation
7. 07*

   A detailed study of the stability of vortons

   R. A. Battye🇬🇧 · S. J. Cotterill🇬🇧 · J. A. Pearson🇬🇧

   We construct and simulate the dynamics of gauged vortons - circular loops of cosmic string supported by the angular momentum of trapped charge and current and provide additional details on the fully stable vorton that we have previously presented. We find that their existence and dynamical properties can be accurately predicted by an analysis based on infinite, straight superconducting strings if an additional constraint on their phase frequency is satisfied. We show a good quantitative agreement with the thin string approximation (TSA) and provide evidence that curvature corrections are inversely proportional to the vorton radius. This is verified with an energy minimisation algorithm that produces vorton solutions and subsequent axial and full three dimensional evolution codes. We find that we can predict the frequencies of each mode of oscillation, determine which modes are unstable and calculate the growth rate of the unstable modes to a high degree of accuracy.

   hep-phastro-ph.COhep-thJHEP(2022)·14 citations
8. 08*

   High Quality Axion via a Doubly Composite Dynamics

   Seung J. Lee🇰🇷 · Yuichiro Nakai🇨🇳 · Motoo Suzuki🇨🇳

   We explore a new framework that furnishes a mechanism to simultaneously address the electroweak naturalness problem and the axion high quality problem. The framework is based on a doubly composite dynamics where the second confinement takes place after the CFT encounters the first confinement and the theory flows into another conformal fixed point. For a calculable example, we present a holographic dual description of the 4D model via a warped extra dimension model with three 3-branes. While the hierarchy problem is taken cared of by the localization of the Higgs fields on the TeV brane just as in the original Randall-Sundrum model, the Peccei-Quinn (PQ) symmetry is realized as a gauge symmetry in the bulk of the extra dimension to solve the axion quality problem. We introduce a 5D scalar field whose potential at the intermediate brane drives spontaneous breaking of the PQ symmetry. Then, the PQ breaking scale is given by the scale of the intermediate brane and is naturally small compared to the Planck scale. The axion bulk profile is significantly suppressed around the UV brane, which protects the axion from gravitational violations of the PQ symmetry on the UV brane. Our model genuinely predicts the existence of the Kaluza-Klein excitations of the QCD axion at around the TeV scale and relatively light extra Higgs bosons.

   hep-phhep-thJHEP(2022)·15 citations
9. 09*

   Dijet Production in Neutral Current and Charged Current Polarized Deep Inelastic Scattering

   Ignacio Borsa🇦🇷 · Daniel de Florian🇦🇷 · Iván Pedron🇦🇷

   We calculate the fully differential Next-to-Leading Order (NLO) corrections to (longitudinally) polarized dijet production in deep inelastic scattering, featuring both neutral current and charged current processes. We also analyze their phenomenological impact in the Electron-Ion Collider (EIC) kinematics.

   hep-phPRD(2022)·8 citations
10. 10*

    What a direct neutrino mass measurement might teach us about the dark sector

    M. Klasen🇩🇪

    Searches for Dark Matter suggest that it couples to ordinary matter only very weakly and possibly only through the Higgs or other scalar bosons. On the other hand, neutrinos might not couple to the Higgs boson directly, but only through a loop of Dark Matter particles, which would naturally explain the small neutrino masses. We demonstrate that current experimental constraints on such a ``scotogenic'' scenario allow to make the linear dependence of the lightest neutrino mass on the dark sector-Higgs coupling explicit, so that a measurement by the KATRIN experiment would directly determine its value.

    hep-phMoscow Univ.Phys.Bull.(2022)·0 citations
11. 11*

    Quantum field theoretical structure of electrical conductivity of cold and dense fermionic matter in the presence of a magnetic field

    Sarthak Satapathy🇮🇳 · Snigdha Ghosh🇮🇳 · Sabyasachi Ghosh🇮🇳

    We have gone through a detailed calculation of the two-point correlation function of vector currents at finite density and magnetic field by employing the real time formalism of finite temperature field theory and Schwinger's proper time formalism. With respect to the direction of external magnetic field, the parallel and perpendicular components of electric conductivity for the degenerate relativistic fermionic matter are obtained from the zero momentum limit of the current-current correlator, owing to Kubo formula. Our quantum field theoretical expressions and numerical estimations are compared with the same, obtained from the relaxation time approximation methods of kinetic theory and its Landau quantized extension, which may be called as classical and quantum results respectively. All the results are merged in the classical domain i.e. high density and low magnetic field region but in the remaining (quantum) domain, quantum results carry a quantized information like Shubnikov-de Haas oscillation along density and magnetic field axes. We have obtained completely new quantum field theoretical expression for perpendicular conductivity of degenerate relativistic fermionic matter. Interestingly, our quantum field theoretical calculation provide a new mathematical form of cyclotron frequency with respect to its classical definition, which might require more future research to interpret the phenomena.

    hep-phnucl-thPRD(2022)·18 citations
12. 12*

    Axion emission from nuclear magnetic dipole transitions

    R. Massarczyk🇺🇸 · P.-H. Chu🇺🇸 · S.R. Elliott🇺🇸

    Nuclear transitions are one possible source of axions but past searches were restricted to specifc transitions. In this manuscript, we propose to extend the search for axions and axion-like particles to more a complex environment that would result in a number of correlated observables. By including creation mechanisms that have their origin in the Carbon-Nitrogen-Oxygen (CNO) cycle, we show that the search for solar axions should not only be restricted to the keV-mass region. We discuss limitations, such as the lifetime and the mass, that create a challenge for an Earth-bound experiments. We show that it is possible to use the same creation mechanisms as used in solar axions to search with a comparable rate at nuclear power reactors.

    hep-phhep-exnucl-exPRD(2022)·16 citations
13. 13*

    Solar constraints on captured electrophilic dark matter

    Debajit Bose🇮🇳 · Tarak Nath Maity🇮🇳 · Tirtha Sankar Ray🇮🇳

    Dark matter captured by interaction with electrons inside the Sun may annihilate via long-lived mediator to produce observable gamma ray signals. We utilize solar gamma ray flux measurements from the Fermi Large Area Telescope and High Altitude Water Cherenkov observatory to put bounds on the dark matter electron scattering cross-section. We find that our limits are four to six orders of magnitude stronger than the existing limits for dark matter masses ranging between GeV to PeV scale.

    hep-phastro-ph.HEastro-ph.SRPRD(2022)·27 citations
14. 14*

    New physics behind the new muon $g$-2 puzzle?

    Luca Di Luzio🇮🇹 · Antonio Masiero🇮🇹 · Paride Paradisi🇮🇹 · Massimo Passera🇮🇹

    The recent measurement of the muon $g$-2 at Fermilab confirms the previous Brookhaven result. The leading hadronic vacuum polarization (HVP) contribution to the muon $g$-2 represents a crucial ingredient to establish if the Standard Model prediction differs from the experimental value. A recent lattice QCD result by the BMW collaboration shows a tension with the low-energy $e^{+}{e}^{-}\to \text{hadrons}$ data which are currently used to determine the HVP contribution. We refer to this tension as the new muon $g$-2 puzzle. In this Letter we consider the possibility that new physics contributes to the $e^{+}{e}^{-}\to \text{hadrons}$ cross-section. This scenario could, in principle, solve the new muon $g$-2 puzzle. However, we show that this solution is excluded by a number of experimental constraints.

    hep-phhep-exhep-latPLB(2022)·34 citations
15. 15*

    Soft photon bremsstrahlung at next-to-leading power

    Domenico Bonocore🇩🇪 · Anna Kulesza🇩🇪

    The emission of soft radiation provides a fundamental probe of the consistency of the underlying quantum field theory. Correspondingly, the measurement of the soft photon bremsstrahlung, such as the one proposed with the planned future upgrade of the ALICE experiment at the LHC, is of great interest. In this letter we explore the possibility to implement analytic techniques that have been recently developed for soft gluon resummation at Next-to-Leading-Power (NLP) in the context of the soft photon spectrum. We provide a formula for the differential cross-section with shifted kinematics that is particularly suitable for numerical implementations. We also discuss the impact of loop corrections to Low's theorem due to radiative jet functions.

    hep-phhep-exnucl-exnucl-thPLB(2022)·20 citations
16. 16*

    Implications of LHCb Data for Lepton Flavour Universality Violation

    T. Hurth🇩🇪 · F. Mahmoudi🇫🇷 · D. Martinez Santos🇪🇸 · S. Neshatpour🇮🇹

    We analyse the new physics implications of theoretically clean $b\to s$ observables in a model-independent approach and compare their coherence with the implications of other rare $B$-decays. A statistical comparison is done between the New Physics explanation and hadronic contributions as the source of the anomalies in angular observables of the $B\to K^{\ast }\mu \mu$ decay. We make projections for future measurements that indicate that LHCb will be in the position to discover lepton non-universality via a single observable using the Run 3 data. The global fit of rare $B$-decays is given within a multidimensional fit involving all the 20 relevant Wilson coefficients.

    hep-phPoS(2022)·1 citation
17. 17*

    Dark Unification: a UV-complete Theory of Asymmetric Dark Matter

    Clara Murgui🇺🇸 · Kathryn M. Zurek🇺🇸

    Motivated by the observed ratio of dark matter to baryon mass densities, ${\rho }_D/{\rho }_B\simeq 5$, we propose a theory of dark-color unification. In this theory, the dark to visible baryon masses are fixed by the ratio of dark to visible confinement scales, which are determined to be nearby in mass through the unification of the dark and visible gauge theories at a high scale. Together with a mechanism for darko-baryo-genesis, which arises naturally from the grand unification sector, the mass densities of the two sectors must be nearby, explaining the observed mass density of dark matter. We focus on the simplest possible example of such a theory, where Standard Model color $SU(3{)}_C$ is unified with dark color $SU(2{)}_D$ into $SU(5)$ at an intermediate scale of around $10^8-10^9$ GeV. The dark baryon consists of two dark quarks in an isotriplet configuration. There are a range of important cosmological, astrophysical and collider signatures to explore, including dark matter self-interactions, early matter domination from the dark hadrons, gravitational wave signatures from the hidden sector phase transition, contributions to flavor observables, as well as Hidden Valley-like signatures at colliders.

    hep-phPRD(2022)·27 citations
18. 18*

    Systematically Testing Singlet Models for $(g-2{)}_{\mu }$

    Rodolfo Capdevilla🇨🇦 · David Curtin🇨🇦 · Yonatan Kahn🇺🇸 · Gordan Krnjaic🇺🇸

    We comprehensively study all viable new-physics scenarios that resolve the muon $(g-2{)}_{\mu }$ anomaly with only Standard Model singlet particles coupled to muons via renormalizable interactions. Since such models are only viable in the MeV -- TeV mass range and require sizable muon couplings, they predict abundant accelerator production through the same interaction that resolves the anomaly. We find that a combination of fixed-target (NA64$\mu$, $M^3$), $B$-factory (BABAR, Belle II), and collider (LHC, muon collider) searches can cover nearly all viable singlets scenarios, independently of their decay modes. In particular, future muon collider searches offer the only certain test of singlets above the GeV scale, covering all higher masses up to the TeV-scale unitarity limit for these models. Intriguingly, we find that $\mathcal{O}(100\mathrm{GeV})$ muon colliders may yield better coverage for GeV-scale singlets compared to TeV-scale concepts, which has important implications for the starting center-of-mass energy of a staged muon collider program.

    hep-phJHEP(2022)·66 citations
19. 19*

    511 keV line constraints on feebly interacting particles from supernovae

    Francesca Calore🇫🇷 · Pierluca Carenza🇸🇪 · Maurizio Giannotti🇺🇸 · Joerg Jaeckel🇩🇪 · Giuseppe Lucente🇮🇹 · Leonardo Mastrototaro🇮🇹 · Alessandro Mirizzi🇮🇹

    Feebly interacting particles with masses with O(10-100) MeV can be copiously produced by core-collapse supernovae (SNe). In this paper we consider the case of MeV-ish sterile neutrinos and dark photons mixed with ordinary neutrinos and photons, respectively. Furthermore, both sterile neutrinos and dark photons may decay into positrons on their route to Earth. Such positrons would annihilate with electrons in the Galactic medium and contribute to the photon flux in the 511 keV line. Using the SPI (SPectrometer on INTEGRAL) observation of this line improves the bounds on the mixing parameters for these particles by several orders of magnitude below what is already excluded by the SN 1987A energy-loss argument.

    hep-phastro-ph.HEPRD(2022)·39 citations
20. 20*

    $(g-2{)}_{e,\mu }$ and strongly interacting dark matter with collider implications

    Anirban Biswas🇰🇷 · Sarif Khan🇩🇪

    The quest for new physics beyond the Standard Model is boosted by the recently observed deviation in the anomalous magnetic moments of muon and electron from their respective theoretical prediction. In the present work, we have proposed a suitable extension of the minimal $L_{\mu }-L_{\tau }$ model to address these two experimental results as the minimal model is unable to provide any realistic solution. In our model, a new Yukawa interaction involving first generation of leptons, a singlet vector like fermion (${\chi }^{\pm }$) and a scalar (either an SU(2)${}_L$ doublet ${\Phi }_2^{\prime }$ or a complex singlet ${\Phi }_4^{\prime }$) provides the additional one loop contribution to $a_e$ only on top of the usual contribution coming from the $L_{\mu }-L_{\tau }$ gauge boson ($Z_{\mu \tau }$) to both electron and muon. The judicious choice of $L_{\mu }-L_{\tau }$ charges to these new fields results in a strongly interacting scalar dark matter in $\mathcal{O}(\mathrm{MeV})$ range after taking into account the bounds from relic density, unitarity and self interaction. The freeze-out dynamics of dark matter is greatly influenced by $3\to 2$ scatterings while the kinetic equilibrium with the SM bath is ensured by $2\to 2$ scatterings with neutrinos where $Z_{\mu \tau }$ plays a pivotal role. The detection of dark matter is possible directly through scatterings with nuclei mediated by the SM $Z$ bosons. Moreover, our proposed model can also be tested in the upcoming $e^{+}{e}^{-}$ colliders by searching opposite sign di-electron and missing energy signal i.e. $e^{+}{e}^{-}\to {\chi }^{+}{\chi }^{-}\to e^{+}{e}^{-}{\cancel{E}}_T$ at the final state.

    hep-phJHEP(2022)·19 citations
21. 21*

    Dark matter component in hadronic models with short-range correlations

    O. Lourenço🇧🇷 · T. Frederico🇧🇷 · M. Dutra🇧🇷

    A relativistic mean field hadronic model with a dark matter (DM) particle coupled to nucleons including short-range correlations (SRC) is applied to study neutron stars (NS). The lightest neutralino is chosen as the dark particle candidate, which interacts with nucleons by the exchange of Higgs bosons. A detailed thermodynamical analysis shows that the contribution of the DM fermions to the energy density of the matter composed by these particles and nucleons is completely dominated by the DM kinetic terms. The model reproduces satisfactorily the constraints on the mass-radius diagram obtained from the analysis of the combined data from the NICER mission, LIGO and Virgo collaborations, and mass measurements from radio observations. We show that the SRC balance the reduction of the neutron star mass due to the DM component, and because of that the model is able to present more massive NS. We also present a study of the effect, in the NS mass-radius profiles, of the uncertainties in some bulk parameters related to the hadronic sector. We find that it is possible to generate parametrizations, with DM content, compatible with the recent astrophysical constraints and with the uncertainty in the symmetry energy slope obtained from the results reported by the updated Lead Radius EXperiment (PREX-2).

    ↳ nucl-thastro-ph.HEhep-phPRD(2022)·35 citations
22. 22*

    Pseudoscalar transition form factors and the hadronic light-by-light contribution to the muon $g-2$

    Antoine Gérardin🇫🇷 · Jana N. Guenther🇩🇪 · Lukas Varnhorst🇩🇪 · Willem E. A. Verplanke🇫🇷

    We present preliminary results from our calculation of the pseudoscalar transition form factors of the $\eta$ and ${\eta }^{\prime }$ mesons using staggered quarks on $N_f=2+1+1$ gauge ensembles generated by the Budapest-Marseille-Wuppertal collaboration. These transition form factors are an important input for the hadronic light-by-light contribution to the muon $(g-2)$. We first elaborate on the extraction of the masses of the $\eta$ and ${\eta }^{\prime }$ mesons, that mix under the dynamics of QCD. Thereafter, we show our preliminary results for the pseudoscalar transition form factors, focusing on the $\eta$ meson in the absence of mixing.

    ↳ hep-lathep-phPoS(2022)·5 citations
23. 23*

    Neutrinoless double-beta decay: combining quantum Monte Carlo and the nuclear shell model with the generalized contact formalism

    Ronen Weiss🇺🇸 · Pablo Soriano🇪🇸 · Alessandro Lovato🇺🇸 · Jaview Menendez🇪🇸 · R. B. Wiringa🇺🇸

    We devise a framework based on the generalized contact formalism that combines the nuclear shell model and quantum Monte Carlo methods and compute the neutrinoless double-beta decay of experimentally relevant nuclei, including ${}^{76}$Ge, ${}^{130}$Te, and ${}^{136}$Xe. In light nuclei, we validate our nuclear matrix element calculations by comparing against accurate variational Monte Carlo results. Due to additional correlations captured by quantum Monte Carlo and introduced within the generalized contact formalism, in heavier systems, we obtain long-range nuclear matrix elements that are about 30% smaller than previous shell-model results. We also evaluate the recently recognized short-range nuclear matrix element estimating its coupling by the charge-independence-breaking term of the Argonne $v_{18}$ potential used in the Monte Carlo calculations. Our results indicate an enhancement of the total nuclear matrix element by around 30%.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2022)·50 citations
24. 24*

    On the Photoproduction Reactions $\gamma d\to \pi NN$

    William J. Briscoe (GWU)🇺🇸 · Alexander E. Kudryavtsev (ITEP)🇺🇸 · Igor I. Strakovsky (GWU)🇺🇸 · Vladimir E. Tarasov (ITEP)🇷🇺 · Ron L. Workman (GWU)🇺🇸

    A review of our works providing a theoretical description of incoherent pion photoproduction on the deuteron is presented. The existing $\gamma d\to \pi NN$ data are analysed, especially those obtained more recently by the CLAS Collaboration at JLab, the A2 Collaboration at MAMI at Mainz, and the PION@MAX-lab Collaboration at Lund. A procedure, which accounts for the final state interactions (FSI), is applied to extract $\gamma n\to \pi N$ differential cross sections from the deuteron data. The role of FSI is discussed. We also comment on the results of other works in connection with some discrepancies seen in comparing the model with experiment. The electromagnetic properties of baryon $N^{\ast }$ resonances, improved using the extracted $\gamma n\to \pi N$ differential cross sections, are presented. A model description of the cross section data from charged-pion photoproduction reactions $\gamma d\to {\pi }^{\pm }NN$ near threshold is also given. The $\gamma d\to {\pi }^{-}pp$ data are used to extract the $E_{0+}$ multipole and total crsoss sections of the reaction $\gamma n\to {\pi }^{-}p$ near threshold.

    ↳ nucl-thhep-exhep-phnucl-exEPJA(2022)·14 citations
25. 25*

    Aspects of finite temperature QCD towards the chiral limit

    Anirban Lahiri🇩🇪

    QCD under extreme conditions has been studied for a long time, and the chiral limit has been a grey area mostly. In this write-up of my talk, I review some of the recent developments made by the community to unveil various features of QCD towards the chiral limit, which includes calculation of the chiral critical temperature and determination of the order of chiral phase transition for various numbers of flavors. Acknowledging the importance of the studies regarding the effective restoration of $U_A(1)$, I try to give a comprehensive overview about the various studies done in the last few years in a comparative manner to realize the current status of the community in this regard. I also discuss very recent efforts about the relevance of various energy-like observables w.r.t. the chiral phase transition.

    ↳ hep-lathep-phnucl-exnucl-thPoS(2022)·30 citations
26. 26*

    Vortices in Black Holes

    Gia Dvali🇩🇪 · Florian Kuhnel🇩🇪 · Michael Zantedeschi🇩🇪

    We argue that black holes admit vortex structure. This is based both on a graviton-condensate description of a black hole as well as on a correspondence between black holes and generic objects with maximal entropy compatible with unitarity, so-called saturons. We show that due to vorticity, a $Q$-ball-type saturon of a calculable renormalizable theory obeys the same extremality bound on the spin as the black hole. Correspondingly, a black hole with extremal spin emerges as a graviton condensate with vorticity. This offers a topological explanation for the stability of extremal black holes against Hawking evaporation. Next, we show that in the presence of mobile charges, the global vortex traps a magnetic flux of the gauge field. This can have macroscopically-observable consequences. For instance, the most powerful jets observed in active galactic nuclei can potentially be accounted for. As a signature, such emissions can occur even without a magnetized accretion disk surrounding the black hole. The flux entrapment can provide an observational window to various hidden sectors, such as millicharged dark matter.

    ↳ hep-thastro-ph.COgr-qchep-phPRL(2022)·37 citations
27. 27*

    Dynamics of Non-minimally Coupled Scalar Fields in the Jordan Frame

    Daniel G. Figueroa🇪🇸 · Adrien Florio🇺🇸 · Toby Opferkuch🇨🇭 · Ben A. Stefanek🇨🇭

    The presence of scalar fields with non-minimal gravitational interactions of the form $\xi |\varphi {|}^{2}R$ may have important implications for the physics of the early universe. While many studies solve the dynamics of non-minimally coupled scalars in the Einstein frame, where gravity is simply described by the Einstein-Hilbert action, we instead propose a procedure to solve the dynamics directly in the original Jordan frame where the non-minimal couplings are maintained explicitly. Our algorithm can be applied to scenarios that include minimally coupled fields and an arbitrary number of non-minimally coupled scalars, with the expansion of the universe sourced by all fields present. This includes situations when the dynamics become fully inhomogeneous, fully non-linear (due to e.g.~backreaction or mode rescattering effects), and/or when the expansion of the universe is dominated by non-minimally coupled species. As an example, we study geometric preheating with a non-minimally coupled scalar spectator field when the inflaton oscillates following the end of inflation. In the future, our technique may be used to shed light on aspects of the equivalence of the Jordan and Einstein frames at the quantum level.

    ↳ astro-ph.COgr-qchep-phSciPost Phys.(2023)·45 citations
28. 28*

    Breeding realistic D-brane models

    Gregory J. Loges🇺🇸 · Gary Shiu🇺🇸

    Intersecting branes provide a useful mechanism to construct particle physics models from string theory with a wide variety of desirable characteristics. The landscape of such models can be enormous, and navigating towards regions which are most phenomenologically interesting is potentially challenging. Machine learning techniques can be used to efficiently construct large numbers of consistent and phenomenologically desirable models. In this work we phrase the problem of finding consistent intersecting D-brane models in terms of genetic algorithms, which mimic natural selection to evolve a population collectively towards optimal solutions. For a four-dimensional $\mathcal{N}=1$ supersymmetric type IIA orientifold with intersecting D6-branes, we demonstrate that $\mathcal{O}(10^6)$ unique, fully consistent models can be easily constructed, and, by a judicious choice of search environment and hyper-parameters, $\mathcal{O}(30\%)$ of the found models contain the desired Standard Model gauge group factor. Having a sizable sample allows us to draw some preliminary landscape statistics of intersecting brane models both with and without the restriction of having the Standard Model gauge factor.

    ↳ hep-thcs.LGhep-phFortsch.Phys.(2022)·34 citations

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