Thu·Aug 13, 2020Thursday·August 13, 2020

1. 01*

   Large-x resummation of off-diagonal deep-inelastic parton scattering from d-dimensional refactorization

   Martin Beneke🇩🇪 · Mathias Garny🇩🇪 · Sebastian Jaskiewicz🇩🇪 · Robert Szafron🇨🇭 · Leonardo Vernazza🇮🇹 · Jian Wang🇨🇳

   The off-diagonal parton-scattering channels $g+{\gamma }^{\ast }$ and $q+{\varphi }^{\ast }$ in deep-inelastic scattering are power-suppressed near threshold $x\to 1$. We address the next-to-leading power (NLP) resummation of large double logarithms of $1-x$ to all orders in the strong coupling, which are present even in the off-diagonal DGLAP splitting kernels. The appearance of divergent convolutions prevents the application of factorization methods known from leading power resummation. Employing $d$-dimensional consistency relations from requiring $1/ϵ$ pole cancellations in dimensional regularization between momentum regions, we show that the resummation of the off-diagonal parton-scattering channels at the leading logarithmic order can be bootstrapped from the recently conjectured exponentiation of NLP soft-quark Sudakov logarithms. In particular, we derive a result for the DGLAP kernel in terms of the series of Bernoulli numbers found previously by Vogt directly from algebraic all-order expressions. We identify the off-diagonal DGLAP splitting functions and soft-quark Sudakov logarithms as inherent two-scale quantities in the large-$x$ limit. We use a refactorization of these scales and renormalization group methods inspired by soft-collinear effective theory to derive the conjectured soft-quark Sudakov exponentiation formula.

   hep-phJHEP(2020)·69 citations
2. 02*

   How to access QED at supercritical Coulomb field

   R. V. Popov🇷🇺 · V. M. Shabaev🇷🇺 · D. A. Telnov🇷🇺 · I. I. Tupitsyn🇷🇺 · I. A. Maltsev🇷🇺 · Y. S. Kozhedub🇷🇺 · A. I. Bondarev🇷🇺 · N. V. Kozin🇷🇺 · X. Ma🇨🇳 · G. Plunien🇩🇪 · T. Stöhlker🇩🇪 · D. A. Tumakov🇷🇺 · V. A. Zaytsev🇷🇺

   In slow collisions of two bare nuclei with the total charge number larger than the critical value, $Z_{\mathrm{cr}}\approx 173$, the initially neutral vacuum can spontaneously decay into the charged vacuum and two positrons. Detection of the spontaneous emission of positrons would be the direct evidence of this fundamental phenomenon. However, the spontaneous emission is generally masked by the dynamical positron emission, which is induced by a strong time-dependent electric field created by the colliding nuclei. In our recent paper [I.A. Maltsev et al., Phys. Rev. Lett. 123, 113401 (2019)] it has been shown that the spontaneous pair production can be observed via measurements of the pair-production probabilities for a given set of nuclear trajectories. In the present paper, we have significantly advanced this study by exploring additional aspects of the process we are interested in. We calculate the positron energy spectra and find that these spectra can give a clear signature of the transition from the subcritical to the supercritical regime. It is found that focusing on a part of the positron spectrum, which accounts for the energy region where the spontaneously created positrons can contribute, allows to get a much stronger evidence of the transition to the supercritical mode, making it very well pronounced in collisions, for example, of two uranium nuclei. The possibility of extending this study to collisions of bare nuclei with neutral atoms is also considered. The probability of a vacancy in the lowest-energy state of a quasimolecule which is formed in collisions of a bare U nucleus with neutral U and Cm atoms has been calculated. The relatively large values of this probability make such collisions suitable for observing the vacuum decay.

   hep-phPRD(2020)·34 citations
3. 03*

   Constraints on light vector mediators through coherent elastic neutrino nucleus scattering data from COHERENT

   M. Cadeddu🇮🇹 · N. Cargioli🇮🇹 · F. Dordei🇮🇹 · C. Giunti🇮🇹 · Y.F. Li🇨🇳 · E. Picciau🇮🇹 · Y.Y. Zhang🇨🇳

   We present new constraints on three different models, the so-called universal, $B-L$ and $L_{\mu }-L_{\tau }$ models, involving a yet to be observed light vector $Z^{\prime }$ mediator, by exploiting the recent observation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) in argon and cesium-iodide performed by the COHERENT Collaboration. We compare the results obtained from a combination of the above data sets with the limits derived from searches in fixed target, accelerator, solar neutrino and reactor CE$\nu$NS experiments, and with the parameter region that could explain the anomalous magnetic moment of the muon. We show that for the universal and the $B-L$ models, the COHERENT data allow us to put stringent limits in the light vector mediator mass, $M_{Z^{\prime }}$, and coupling, $g_{Z^{\prime }}$, parameter space.

   hep-phJHEP(2021)·103 citations
4. 04*

   Shedding New Light on Sterile Neutrinos from XENON1T Experiment

   Soroush Shakeri🇮🇷 · Fazlollah Hajkarim🇩🇪 · She-Sheng Xue🇮🇹

   The XENON1T collaboration recently reported the excess of events from recoil electrons, possibly giving an insight into new area beyond the Standard Model (SM) of particle physics. We try to explain this excess by considering effective interactions between the sterile neutrinos and the SM particles. In this paper, we present an effective model based on one-particle-irreducible interaction vertices at low energies that are induced from the SM gauge symmetric four-fermion operators at high energies. The effective interaction strength is constrained by the SM precision measurements, astrophysical and cosmological observations. We introduce a novel effective electromagnetic interaction between sterile neutrinos and SM neutrinos, which can successfully explain the XENON1T event rate through inelastic scattering of the sterile neutrino dark matter from Xenon electrons. We find that sterile neutrinos with masses around $90$ keV and specific effective coupling can fit well with the XENON1T data where the best fit points preserving DM constraints and possibly describe the anomalies in other experiments.

   hep-phastro-ph.COhep-exJHEP(2020)·35 citations
5. 05*

   Sensitivity of direct detection experiments to neutrino magnetic dipole moments

   D. Aristizabal Sierra🇨🇱 · R. Branada🇨🇱 · O. G. Miranda🇲🇽 · G. Sanchez Garcia🇲🇽

   With large active volume sizes dark matter direct detection experiments are sensitive to solar neutrino fluxes. Nuclear recoil signals are induced by ${}^8$B neutrinos, while electron recoils are mainly generated by the pp flux. Measurements of both processes offer an opportunity to test neutrino properties at low thresholds with fairly low backgrounds. In this paper we study the sensitivity of these experiments to neutrino magnetic dipole moments assuming 1, 10 and 40 tonne active volumes (representative of XENON1T, XENONnT and DARWIN), 0.3 keV and 1 keV thresholds. We show that with nuclear recoil measurements alone a 40 tonne detector could be as competitive as Borexino, TEXONO and GEMMA, with sensitivities of order $8.0\times 10^{-11}{\mu }_B$ at the $90\%$ CL after one year of data taking. Electron recoil measurements will increase sensitivities way below these values allowing to test regions not excluded by astrophysical arguments. Using electron recoil data and depending on performance, the same detector will be able to explore values down to $4.0\times 10^{-12}{\mu }_B$ at the $90\%$ CL in one year of data taking. By assuming a 200-tonne liquid xenon detector operating during 10 years, we conclude that sensitivities in this type of detectors will be of order $10^{-12}{\mu }_B$. Reducing statistical uncertainties may enable improving sensitivities below these values.

   hep-phhep-exJHEP(2020)·24 citations
6. 06*

   Determination of the strong vertices of doubly heavy baryons with pseudoscalar mesons in QCD

   H. I. Alrebdi🇸🇦 · T. M. Aliev🇹🇷 · K. Şimşek🇺🇸

   The strong coupling constant of doubly heavy baryons with light pseudoscalar mesons $\pi$ and $K$ are computed within the light cone sum rules. We take into account two-particle and three-particle distribution amplitudes of the said pseudoscalar mesons. We compare our result with the one existing in the literature.

   hep-phPRD(2020)·19 citations
7. 07*

   Baryon and Lepton Number Violation from Gravitational Waves

   Bartosz Fornal🇺🇸 · Barmak Shams Es Haghi🇺🇸

   We describe a unique gravitational wave signature for a class of models with a vast hierarchy between the symmetry breaking scales. The unusual shape of the signal is a result of the overlapping contributions to the stochastic gravitational wave background from cosmic strings produced at a high scale and a cosmological phase transition at a low scale. We apply this idea to a simple model with gauged baryon and lepton number, in which the high-scale breaking of lepton number is motivated by the seesaw mechanism for the neutrinos, whereas the low scale of baryon number breaking is required by the observed dark matter relic density. The novel signature can be searched for in upcoming gravitational wave experiments.

   hep-phastro-ph.COPRD(2020)·49 citations
8. 08*

   Ultra-peripheral nuclear collisions as a source of heavy quarkonia

   B. Z. Kopeliovich🇨🇱 · M. Krelina🇨🇿 · J. Nemchik🇨🇿 · I. K. Potashnikova🇨🇱

   Heavy quarkonium production in ultra-peripheral nuclear collisions (UPC) is described within the QCD dipole formalism. Realistic quarkonium wave functions in the $Q\bar{Q}$ rest frame are calculated by solving the Schrödinger equation with a subsequent Lorentz boost to high energy. We rely on several realistic $Q\bar{Q}$ potentials, which allow to describe well the quarkonium masses and decay widths, as well as data on diffractive electroproduction of quarkonia on protons. Nuclear effects are calculated with the phenomenological dipole cross sections fitted to DIS data. The higher twist quark shadowing related to the lowest $Q\bar{Q}$ Fock component of the photon, as well as the leading twist gluon shadowing, related to higher components containing gluons, are included. The results for coherent and incoherent photoproduction of charmonia and bottomonia in UPC of heavy nuclei are in good accord with available data from the LHC. They can also be verified in future experiments at electron-ion colliders.

   hep-phnucl-thPRD(2023)·33 citations
9. 09*

   The effective theory of nuclear scattering for a WIMP of arbitrary spin

   Paolo Gondolo (Utah U.)🇺🇸 · Sunghyun Kang🇰🇷 · Stefano Scopel (Sogang U.)🇰🇷 · Gaurav Tomar (Sogang U. and Technical U. of Munich)🇰🇷

   We introduce a systematic approach to characterize the most general non-relativistic WIMP-nucleus interaction allowed by Galilean invariance for a WIMP of arbitrary spin $j_{\chi }$ in the approximation of one-nucleon currents. Five nucleon currents arise from the nonrelativistic limit of the free nucleon Dirac bilinears. Our procedure consists in (1) organizing the WIMP currents according to the rank of the $2j_{\chi }+1$ irreducible operator products of up to $2j_{\chi }$ WIMP spin vectors, and (2) coupling each of the WIMP currents to each of the five nucleon currents. The transferred momentum $q$ appears to a power fixed by rotational invariance. For a WIMP of spin $j_{\chi }$ we find a basis of 4+20$j_{\chi }$ independent operators that exhaust all the possible operators that drive elastic WIMP-nucleus scattering in the approximation of one-nucleon currents. By comparing our operator basis, which is complete, to the operators already introduced in the literature we show that some of the latter for $j_{\chi }=1$ were not independent and some were missing. We provide explicit formulas for the squared scattering amplitudes in terms of the nuclear response functions, which are available in the literature for most of the targets used in WIMP direct detection experiments.

   hep-phastro-ph.COPRD(2021)·28 citations
10. 10*

    Lorentz and permutation invariants of particles III: constraining non-standard sources of parity violation

    Christopher G. Lester🇬🇧 · Ward Haddadin🇬🇧 · Ben Gripaios🇬🇧

    Comparisons of the positive and negative halves of the distributions of parity-odd event variables in particle-physics experimental data can provide sensitivity to sources of non-standard parity violation. Such techniques benefit from lacking first-order dependence on simulations or theoretical models, but have hitherto lacked systematic means of enumerating all discoverable signals. To address that issue this paper seeks to construct sets of parity-odd event variables which may be proved to be able to reveal the existence of any Lorentz-invariant source of non-standard parity violation which could be visible in data consisting of groups of real non space-like four-momenta exhibiting certain permutation symmetries.

    hep-phhep-thInt.J.Mod.Phys.A(2022)·6 citations
11. 11*

    Parity violation in proton-deuteron scattering

    A.I. Milstein🇷🇺 · N.N. Nikolaev🇷🇺 · S.G. Salnikov🇷🇺

    The effects of parity violation in the interaction of relativistic polarized protons and deuterons are discussed. Within Glauber's approach, estimates are obtained for P-odd asymmetries in the total and elastic scattering cross sections, in the deuteron dissociation cross section, and in the inelastic cross section with meson production in a final state. It is shown that, from the point of view of the magnitude of the P-odd effects, the interaction of polarized deuterons with unpolarized protons has an advantage over the interaction of polarized protons with unpolarized deuterons. A significant P-odd asymmetry was found in the dissociation channel of the polarized deuteron.

    hep-phnucl-thJETP Lett.(2020)·4 citations
12. 12*

    Dipole model at Next-to-Leading Order meets HERA data

    G. Beuf🇫🇮 · H. Hänninen🇫🇮 · T. Lappi🇫🇮 · H. Mäntysaari🇫🇮

    Deep inelastic scattering (DIS) total cross section data at small-x as measured by the HERA experiments is well described by Balitsky-Kovchegov (BK) evolution in the leading order dipole picture. Recently the full Next-to-Leading Order (NLO) dipole picture total cross sections have become available for DIS, and a working factorization scheme has been devised which subtracts the soft gluon divergence present at NLO. We report our recently published work in which we make the first comparisons of the NLO DIS total cross sections to HERA data. The non-perturbative initial condition to BK evolution is fixed by fitting the HERA reduced cross section data. As the NLO results for the DIS total cross section are currently available only in the massless quark limit, we also fit a light-quark-only cross section constructed with a parametrization of published total and heavy quark data. We find an excellent description of the HERA data. Since the full NLO BK equation is computationally expensive, we use a number of beyond LO prescriptions for the evolution that include most important higher order corrections enhanced by large transverse logarithms, including the recent version of the equation formulated in terms of the target momentum fraction.

    hep-phnucl-thPoS(2021)·3 citations
13. 13*

    Centrality dependence of nuclear suppression of D mesons in $p$+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV

    Srikanta Kumar Tripathy🇭🇺 · Mohammed Younus🇿🇦 · Sudipan De🇮🇳

    In this paper we have shown theoretical model comparisons with ALICE results for average D mesons (D${}^0$, D${}^{+}$, D${}^{\ast +}$ and $D_s^{+}$) in $p$+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV for various centralities. Transport calculations of AMPT and calculations from heavy quark pQCD model, NLO(MNR) have been used for the study of $p_T$ dependent nuclear modification factors in terms of collision centrality ($Q_{pPb}$) and the central-to-peripheral ratios ($Q_{cp}$) of D mesons. It is found that NLO model with its parametrized $k_T$ broadening scheme produces results those closely match with the published D-meson data of $p$+Pb collisions from ALICE. Likewise AMPT transport calculation shows a strong centrality dependence in results but underestimates the experimental data. The differences of both models with experimental data have been discussed.

    hep-phnucl-th2 citations
14. 14*

    Comparing Traditional and Deep-Learning Techniques of Kinematic Reconstruction for polarisation Discrimination in Vector Boson Scattering

    M. Grossi🇮🇹 · J. Novak🇫🇷 · B. Kersevan🇸🇮 · D. Rebuzzi🇮🇹

    Measuring longitudinally polarised vector boson scattering in WW channel is a promising way to investigate unitarity restoration with the Higgs mechanism and to search for possible physics beyond the Standard Model. In order to perform such a measurement, it is crucial to develop an efficient reconstruction of the full W boson kinematics in leptonic decays with the focus on polarisation measurements. We investigated several approaches, from traditional ones up to advanced deep neural network structures, and we compared their ability to reconstruct the W boson reference frame and to consequently measure the longitudinal fraction W_L in both semi-leptonic and di-leptonic WW decay channels.

    hep-phEPJC(2020)·35 citations
15. 15*

    Symmetries and stabilisers in modular invariant flavour models

    Ivo de Medeiros Varzielas🇵🇹 · Miguel Levy🇵🇹 · Ye-Ling Zhou🇬🇧

    The idea of modular invariance provides a novel explanation of flavour mixing. Within the context of finite modular symmetries ${\Gamma }_N$ and for a given element $\gamma \in {\Gamma }_N$, we present an algorithm for finding stabilisers (specific values for moduli fields ${\tau }_{\gamma }$ which remain unchanged under the action associated to $\gamma$). We then employ this algorithm to find all stabilisers for each element of finite modular groups for $N=2$ to $5$, namely, ${\Gamma }_2\simeq S_3$, ${\Gamma }_3\simeq A_4$, ${\Gamma }_4\simeq S_4$ and ${\Gamma }_5\simeq A_5$. These stabilisers then leave preserved a specific cyclic subgroup of ${\Gamma }_N$. This is of interest to build models of fermionic mixing where each fermionic sector preserves a separate residual symmetry.

    hep-phhep-thJHEP(2020)·53 citations
16. 16*

    Simultaneous extraction of fragmentation functions of light charged hadrons with mass corrections

    Maryam Soleymaninia🇮🇷 · Muhammad Goharipour🇮🇷 · Hamzeh Khanpour🇮🇷 · Hubert Spiesberger🇩🇪

    Achieving the highest possible precision for theoretical predictions at the present and future high-energy lepton and hadron colliders requires a precise determination of fragmentation functions (FFs) of light and heavy charged hadrons from a global QCD analysis with great accuracy. We describe a simultaneous determination of unpolarized FFs of charged pions, charged kaons and protons/antiprotons from single-inclusive hadron production in electron-positron annihilation (SIA) data at next-to-leading order and next-to-next-to-leading order accuracy in perturbative QCD. A new set of FFs, called {\tt SGKS20}, is presented. We include data for identified light charged hadrons (${\pi }^{\pm },K^{\pm }$ and $p/\bar{p}$) as well as for unidentified light charged hadrons, $h^{\pm }$ and show that these data have a significant impact on both size and uncertainties of the fragmentation functions. We examine the inclusion of higher-order perturbative QCD corrections and finite-mass effects. We compare the new {\tt SGKS20} FFs with other recent FFs available in the literature and find in general reasonable agreement, but also important differences for some parton species. We show that theoretical predictions obtained from our new FFs are in very good agreement with the analyzed SIA data, especially at small values of $z$. The {\tt SGKS20} FF sets presented in this work are available via the {\tt LHAPDF} interface.

    hep-phhep-exPRD(2021)·16 citations
17. 17*

    Transverse moments of TMD parton densities and ultraviolet divergences

    Ted Rogers🇺🇸

    I review some open questions relating to the large transverse momentum divergences in transverse moments of transverse momentum dependent (TMD) parton correlation func- tions. I also explain, in an abbreviated and summarized form, recent work that shows that the resulting violations of a commonly used integral relation are not perturbatively suppressed. I argue that this implies a need for more precise definitions for the correlation functions used to describe transverse moments.

    hep-phhep-exnucl-thMod.Phys.Lett.A(2020)·9 citations
18. 18*

    Invisible Higgs search through Vector Boson Fusion: A deep learning approach

    Vishal S. Ngairangbam🇮🇳 · Akanksha Bhardwaj🇮🇳 · Partha Konar🇮🇳 · Aruna Kumar Nayak🇮🇳

    Vector boson fusion proposed initially as an alternative channel for finding heavy Higgs has now established itself as a crucial search scheme to probe different properties of the Higgs boson or for new physics. We explore the merit of deep-learning entirely from the low-level calorimeter data in the search for invisibly decaying Higgs. Such an effort supersedes decades-old faith in the remarkable event kinematics and radiation pattern as a signature to the absence of any color exchange between incoming partons in the vector boson fusion mechanism. We investigate among different neural network architectures, considering both low-level and high-level input variables as a detailed comparative analysis. To have a consistent comparison with existing techniques, we closely follow a recent experimental study of CMS search on invisible Higgs with 36 fb${}^{-1}$ data. We find that sophisticated deep-learning techniques have the impressive capability to improve the bound on invisible branching ratio by a factor of three, utilizing the same amount of data. Without relying on any exclusive event reconstruction, this novel technique can provide the most stringent bounds on the invisible branching ratio of the SM-like Higgs boson. Such an outcome has the ability to constraint many different BSM models severely.

    hep-phhep-exEPJC(2020)·19 citations
19. 19*

    Radiative Neutrino Masses in the ${\nu }_R$MSSM

    Pablo Candia da Silva🇬🇧 · Apostolos Pilaftsis🇬🇧

    We present a complete analysis of scenarios with radiatively generated neutrino masses that may occur in the Minimal Supersymmetric Standard Model with low-scale right-handed neutrinos. For brevity, we call such a model the ${\nu }_R$MSSM. We pay particular attention to the impact of the non-renormalization theorem of supersymmetry (SUSY) on the loop-induced neutrino masses, by performing our computations in the weak and flavour bases. In particular, we find that the smallness of the observed light neutrino masses may naturally arise due to a soft SUSY-screening effect from a nearly supersymmetric singlet neutrino sector. The profound phenomenological and cosmological implications that may originate from this screening phenomenon in the ${\nu }_R$MSSM and its minimal extensions are discussed.

    hep-phPRD(2020)·8 citations
20. 20*

    Central exclusive production of scalar and pseudoscalar charmonia in the light-front $k_T$-factorization approach

    Izabela Babiarz🇵🇱 · Roman Pasechnik🇸🇪 · Wolfgang Schäfer🇵🇱 · Antoni Szczurek🇵🇱

    We study exclusive production of scalar ${\chi }_{c0}\equiv {\chi }_c(0^{++})$ and pseudoscalar ${\eta }_c$ charmonia states in proton-proton collisions at the LHC energies. The amplitudes for $gg\to {\chi }_{c0}$ as well as for $gg\to {\eta }_c$ mechanisms are derived in the $k_T$-factorization approach. The $pp\to pp{\eta }_c$ reaction is discussed for the first time. We have calculated rapidity, transverse momentum distributions as well as such correlation observables as the distribution in relative azimuthal angle and $(t_1,t_2)$ distributions. The latter two observables are very different for ${\chi }_{c0}$ and ${\eta }_c$ cases. In contrast to the inclusive production of these mesons considered very recently in the literature, in the exclusive case the cross section for ${\eta }_c$ is much lower than that for ${\chi }_{c0}$ which is due to a special interplay of the corresponding vertices and off-diagonal UGDFs used to calculate the cross sections. We present the numerical results for the key observables in the framework of potential models for the light-front quarkonia wave functions. We also discuss how different are the absorptive corrections for both considered cases.

    hep-phPRD(2020)·7 citations
21. 21*

    Interference effect in lepton number violating and conserving meson decays for a left-right symmetric model

    Rohini M. Godbole🇮🇳 · Siddharth P. Maharathy🇮🇳 · Sanjoy Mandal🇪🇸 · Manimala Mitra🇮🇳 · Nita Sinha🇮🇳

    We study the effect of interference on the lepton number violating~(LNV) and lepton number conserving~(LNC) three-body meson decays $M_1^{+}\to l_i^{+}{l}_j^{\pm }{\pi }^{\mp }$, that arise in a TeV scale Left Right Symmetric model~(LRSM) with degenerate or nearly degenerate right handed~(RH) neutrinos. LRSM contains three RH neutrinos and a RH gauge boson. The RH neutrinos with masses in the range of $M_N\sim$ (MeV - few GeV) can give resonant enhancement in the semi-leptonic LNV and LNC meson decays. In the case, where only one RH neutrino contributes to these decays, the predicted new physics branching ratio of semi-leptonic LNV and LNC meson decays $M_1^{+}\to l_i^{+}{l}_j^{+}{\pi }^{-}$ and $M_1^{+}\to l_i^{+}{l}_j^{-}{\pi }^{+}$ are equal. We find that with at least two RH neutrinos contributing to the process, the LNV and LNC decay rates can differ. Depending on the neutrino mixing angles and $CP$ violating phases, the branching ratios of LNV and LNC decay channels mediated by the heavy neutrinos can be either enhanced or suppressed, and the ratio of these two rates can differ from unity.

    hep-phhep-exPRD(2021)·24 citations
22. 22*

    The Sivers Asymmetry in Hadronic Dijet Production

    Zhong-Bo Kang🇺🇸 · Kyle Lee🇺🇸 · Ding Yu Shao🇺🇸 · John Terry🇺🇸

    We study the single spin asymmetry in the back-to-back dijet production in transversely polarized proton-proton collisions. Such an asymmetry is generated by the Sivers functions in the incoming polarized proton. We propose a QCD formalism in terms of the transverse momentum dependent parton distribution functions, which allow us to resum the large logarithms that arise in the perturbative calculations. We make predictions for the Sivers asymmetry of hadronic dijet production at the kinematic region that is relevant to the experiment at the Relativistic Heavy Ion Collider (RHIC). We further compute the spin asymmetries in the selected positive and negative jet charge bins, to separate the contributions from $u$- and $d$-quark Sivers functions. We find that both the sign and size of our numerical results are roughly consistent with the preliminary results from the STAR collaboration at the RHIC.

    hep-phhep-exnucl-exnucl-thJHEP(2021)·27 citations
23. 23*

    Comparative Studies of 2HDMs under the Higgs Boson Precision Measurements

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

    We perform comparative studies for four types of the two Higgs Doublet Models (2HDMs) under the precision measurements of the Standard Model (SM) Higgs observables at the proposed Higgs factories. We explore the discovery potential based on the hypothetical deviations in the precision data for the 2HDMs up to one-loop level. We find $5\sigma$ observability from the ${\chi }^2$ fitting in a significant theory parameter space at future Higgs factories. For the Type-I 2HDM, regions with $\cos (\beta -\alpha )\lesssim -0.1$ or $\cos (\beta -\alpha )\gtrsim 0.08$ are discoverable at more than $5\sigma$ level. For the other three types of 2HDMs, the $5\sigma$ region is even bigger: $|\cos (\beta -\alpha )|\gtrsim 0.02$ for $\tan \beta \sim 1$. At small and large values of $\tan \beta$, the region in $\cos (\beta -\alpha )$ is further tightened. We examine the extent to which the different 2HDM theories may be distinguishable from one to the other at the $95\%$ Confidence Level with four benchmark points as case studies. We show that a large part of the parameter space of the other types of 2HDMs can be distinguished from the benchmark points of the target model. The impacts of loop corrections are found to be significant in certain parameter regions.

    hep-phhep-exJHEP(2021)·24 citations
24. 24*

    Primordial Gravitational Wave Signals in Modified Cosmologies

    Nicolás Bernal🇨🇴 · Anish Ghoshal🇮🇹 · Fazlollah Hajkarim🇩🇪 · Gaetano Lambiase🇮🇹

    Modified expansion rates in the early Universe prior to big bang nucleosynthesis are common in modified gravity theories, and can have a significant impact on the generation of dark matter, matter-antimatter asymmetry, primordial black holes and the primordial gravitational wave (PGW) spectrum. Here we study the PGW spectrum in modified gravity theories, in early Universe cosmology. In particular, we consider scalar-tensor and extradimensional scenarios, investigating the detection prospects in current and future GW observatories. For the scalar-tensor case, PGW could be potentially observed by laser interferometers operating in the high-frequency range, while for the extradimensional case they could be detected even at low frequencies with pulsar timing arrays. We find that data from the planned network of several GW detectors operating across various frequency ranges could be able to distinguish between various modified gravity scenarios.

    ↳ gr-qchep-phhep-thJCAP(2020)·81 citations
25. 25*

    The Phase of the BAO on Observable Scales

    Daniel Green🇺🇸 · Alexander K. Ridgway🇺🇸

    The baryon acoustic oscillations (BAO) provide an important bridge between the early universe and the expansion history at late times. While the BAO has primarily been used as a standard ruler, it also encodes recombination era physics, as demonstrated by a recent measurement of the neutrino-induced phase shift in the BAO feature. In principle, these measurements offer a novel window into physics at the time of baryon decoupling. However, our analytic understanding of the BAO feature is limited, particularly for the range of Fourier modes measured in surveys. As a result, it is unclear what the BAO phase teaches us about the early universe beyond what is already known from the cosmic microwave background (CMB). In this paper, we provide a more complete (semi-)analytic treatment of the BAO on observationally relevant scales. In particular, we compute corrections to the frequency and phase of the BAO feature that arise from higher order effects which occur in the tight coupling regime and during baryon decoupling. The total phase shift we find is comparable to a few percent shift in the BAO scale (frequency) and thus relevant in current data. Our results include an improved analytic calculation of the neutrino induced phase shift template that is in close agreement with the numerically determined template used in measurements of the CMB and BAO.

    ↳ astro-ph.COhep-phJCAP(2020)·19 citations
26. 26*

    Bubble nucleation around heterogeneities in ${\varphi }^4$-field theories

    Juan F. Marin🇨🇱

    Localised heterogeneities have been recently discovered to act as bubble-nucleation sites in nonlinear field theories. Vacuum decay seeded by black holes is one of the most remarkable applications. This article proposes a simple and exactly solvable ${\varphi }^4$ model exhibiting bubble nucleation around localised heterogeneities. Bubbles with a rich dynamical behaviour are observed depending on the topological properties of the heterogeneity. The linear stability analysis of soliton-bubbles predicts the formation of oscillating bubbles and the insertion of new bubbles inside an expanding precursor bubble. Numerical simulations in 2+1 dimensions are in good agreement with theoretical predictions.

    ↳ nlin.PShep-ph0 citations
27. 27*

    Prediction of Tunable Spin-Orbit Gapped Materials for Dark Matter Detection

    Katherine Inzani🇺🇸 · Alireza Faghaninia🇺🇸 · Sinéad M. Griffin🇺🇸

    New ideas for low-mass dark matter direct detection suggest that narrow band gap materials, such as Dirac semiconductors, are sensitive to the absorption of meV dark matter or the scattering of keV dark matter. Here we propose spin-orbit semiconductors - materials whose band gap arises due to spin-orbit coupling - as low-mass dark matter targets owing to their ~10 meV band gaps. We present three material families that are predicted to be spin-orbit semiconductors using Density Functional Theory (DFT), assess their electronic and topological features, and evaluate their use as low-mass dark matter targets. In particular, we find that that the tin pnictide compounds are especially suitable having a tunable range of meV-scale band gaps with anisotropic Fermi velocities allowing directional detection. Finally, we address the pitfalls in the DFT methods that must be considered in the ab initio prediction of narrow-gapped materials, including those close to the topological critical point.

    ↳ cond-mat.mtrl-sciastro-ph.HEastro-ph.IMhep-ex+1PRResearch(2021)·25 citations
28. 28*

    Charmed and $\varphi$ meson decay constants from 2+1-flavor lattice QCD

    Ying Chen🇨🇳 · Wei-Feng Chiu🇨🇳 · Ming Gong🇨🇳 · Zhaofeng Liu🇨🇳 · Yunheng Ma (chiQCD Collaboration)🇨🇳

    On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical pion mass, we calculate the decay constants of $D_s^{(\ast )}$, $D^{(\ast )}$ and $\varphi$. The lattice size is $48^3\times 96$, which corresponds to a spatial extension of $\sim 5.5$ fm with the lattice spacing $a\approx 0.114$ fm. For the valence light, strange and charm quarks, we use overlap fermions at several mass points close to their physical values. Our results at the physical point are $f_D=213(5)$ MeV, $f_{D_s}=249(7)$ MeV, $f_{D^{\ast }}=234(6)$ MeV, $f_{D_s^{\ast }}=274(7)$ MeV, and $f_{\varphi }=241(9)$ MeV. The couplings of $D^{\ast }$ and $D_s^{\ast }$ to the tensor current ($f_V^T$) can be derived, respectively, from the ratios $f_{D^{\ast }}^T/f_{D^{\ast }}=0.91(4)$ and $f_{D_s^{\ast }}^T/f_{D_s^{\ast }}=0.92(4)$, which are the first lattice QCD results. We also obtain the ratios $f_{D^{\ast }}/f_D=1.10(3)$ and $f_{D_s^{\ast }}/f_{D_s}=1.10(4)$, which reflect the size of heavy quark symmetry breaking in charmed mesons. The ratios $f_{D_s}/f_D=1.16(3)$ and $f_{D_s^{\ast }}/f_{D^{\ast }}=1.17(3)$ can be taken as a measure of SU(3) flavor symmetry breaking.

    ↳ hep-lathep-exhep-phCPC(2021)·38 citations
29. 29*

    Two-point function of the energy-momentum tensor and generalised conformal structure

    Claudio Corianò🇮🇹 · Luigi Delle Rose🇮🇹 · Kostas Skenderis🇬🇧

    Theories with generalised conformal structure contain a dimensionful parameter, which appears as an overall multiplicative factor in the action. Examples of such theories are gauge theories coupled to massless scalars and fermions with Yukawa interactions and quartic couplings for the scalars in spacetime dimensions other than 4. Many properties of such theories are similar to that of conformal field theories (CFT), and in particular their 2-point functions take the same form as in CFT but with the normalisation constant now replaced by a function of the effective dimensionless coupling $g$ constructed from the dimensionful parameter and the distance separating the two operators. Such theories appear in holographic dualities involving non-conformal branes and this behaviour of the correlators has already been observed at strong coupling. Here we present a perturbative computation of the two-point function of the energy-momentum tensor to two loops in dimensions $d=3,5$, confirming the expected structure and determining the corresponding functions of $g$ to this order, including the effects of renormalisation. We also discuss the d=4 case for comparison. The results for $d=3$ are relevant for holographic cosmology, and in this case we also study the effect of a ${\Phi }^6$ coupling, which while marginal in the usual sense it is irrelevant from the perspective of the generalised conformal structure. Indeed, the effect of such coupling in the 2-point function is washed out in the IR but it modifies the UV.

    ↳ hep-thhep-phEPJC(2021)·15 citations
30. 30*

    Closed Strings and Weak Gravity from Higher-Spin Causality

    Jared Kaplan🇺🇸 · Sandipan Kundu🇺🇸

    We combine old and new quantum field theoretic arguments to show that any theory of stable or metastable higher spin particles can be coupled to gravity only when the gravity sector has a stringy structure. Metastable higher spin particles, free or interacting, cannot couple to gravity while preserving causality unless there exist higher spin states in the gravitational sector much below the Planck scale $M_{\mathrm{pl}}$. We obtain an upper bound on the mass ${\Lambda }_{\mathrm{gr}}$ of the lightest higher spin particle in the gravity sector in terms of quantities in the non-gravitational sector. We invoke the CKSZ uniqueness theorem to argue that any weakly coupled UV completion of such a theory must have a gravity sector containing infinite towers of asymptotically parallel, equispaced, and linear Regge trajectories. Consequently, gravitational four-point scattering amplitudes must coincide with the closed string four-point amplitude for $s,t\gg 1$, identifying ${\Lambda }_{\mathrm{gr}}$ as the string scale. Our bound also implies that all metastable higher spin particles in 4d with masses $m\ll {\Lambda }_{\mathrm{gr}}$ must satisfy a weak gravity condition.

    ↳ hep-thgr-qchep-phJHEP(2021)·19 citations
31. 31*

    Natural inflation, strong dynamics, and the role of generalized anomalies

    Mohamed M. Anber🇺🇸 · Stephen Baker🇺🇸

    We revisit models of natural inflation and show that the single-field effective theory described by the potential $V(a)\sim \cos \frac{a}{f}$ breaks down as the inflaton $a$ makes large-field excursions, even for values of $f$ smaller than the Planck scale. In order to remedy the problem, we modify the potential in order to account for the heavy degrees of freedom (hadrons) that become intertwined with the light inflaton as the latter rolls down its potential. By embedding the low energy degrees of freedom into an ultraviolet complete gauge theory, we argue that the intertwining between the two scales can be explained as the result of a generalized mixed 't Hooft anomaly between the discrete chiral symmetry and background fractional fluxes in the baryon number, color, and flavor directions. Further, we study the multi-field inflation and show that it entertains rich dynamics. Inflating near the hilltop excites the hadrons and spoils the slow-roll parameters, in contradistinction with the expectations in the single-field inflation. Nevertheless, we identify a safe zone where inflation can proceed successfully. We determine the conditions under which the Universe inflates by at least $60$ e-foldings and inflation leads to a power spectrum and tensor to scalar ratio that are consistent with the Cosmic Microwave Background data.

    ↳ hep-thastro-ph.COhep-phPRD(2020)·8 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.