Wed·Aug 25, 2021Wednesday·August 25, 2021

1. 01*

   Coherent energy loss effects in dihadron azimuthal angular correlations in Deep Inelastic Scattering at small $x$

   Filip Bergabo🇺🇸 · Jamal Jalilian-Marian🇺🇸

   We perform an exploratory study of the role of coherent, medium-induced energy loss in azimuthal angular correlations in dihadron production in Deep Inelastic Scattering (DIS) at small $x$ where the target proton/nucleus is modeled as a Color Glass Condensate. In this approach coherent radiative energy loss is part of the higher order corrections to the leading order dihadron production cross section. We include the effects of both gluon saturation and coherent radiative energy loss and show that radiative cold-matter energy loss has a significant effect on the so-called coincidence probability for the back to back production of dihadrons in DIS. We also define a double ratio of coincidence probabilities for a nucleus and proton targets and show that it is very robust against higher order radiative corrections.

   hep-phnucl-thNPA(2022)·16 citations
2. 02*

   Mass spectra of doubly heavy tetraquarks in an improved chromomagnetic interaction model

   Tao Guo🇨🇳 · Jianing Li🇨🇳 · Jiaxing Zhao🇨🇳 · Lianyi He🇨🇳

   Doubly heavy tetraquark states are the prime candidates for tightly bound exotic states. We present a systematic study of the mass spectra of the $S$-wave doubly heavy tetraquark states $QQ\bar{q}\bar{q}$ ($q=u,d,s$ and $Q=c,b$) with different quantum numbers $J^P=0^{+}$, $1^{+}$, and $2^{+}$ in the framework of the improved chromomagnetic interaction (ICMI) model. The parameters in the ICMI model are obtained by fitting the conventional hadron spectra and are used directly to predict the masses of the tetraquark states. For heavy quarks, the uncertainties of the parameters are obtained by comparing the masses of doubly and triply heavy baryons with those given by lattice QCD, QCD sum rules, and potential models. Several compact and stable bound states are found in both the doubly charmed and doubly bottomed tetraquark systems. The predicted mass of the $cc\bar{u}\bar{d}$ state is consistent with the recent measurement from the LHCb collaboration.

   hep-phnucl-thPRD(2022)·61 citations
3. 03*

   High $P_T$ Higgs excess as a signal of non-local QFT at the LHC

   Xing-Fu Su🇹🇼 · You-Ying Li🇹🇼 · Rosy Nicolaidou🇫🇷 · Min Chen🇹🇼 · Hsin-Yeh Wu🇹🇼 · Stathes Paganis🇹🇼

   Non-local extensions of the Standard Model with a non-locality scale ${\Lambda }_{NL}$ have the effect of smearing the pointlike vertices of the Standard Model. At energies significantly lower than ${\Lambda }_{NL}$ vertices appear pointlike, while beyond this scale all beta functions vanish and all couplings approach a fixed point leading to scale invariance. Non-local SM extensions are ghost free, with the non-locality scale serving as an effective cutoff to radiative corrections of the Higgs mass. We argue that the data expected to be collected at the LHC phase 2 will have a sensitivity to non-local effects originating from a non-locality scale of a few TeV. Using an infinite derivative prescription, we study modifications to heavy vector-boson cross sections that can lead to an enhanced production of boosted Higgs bosons in a region of the kinematic phase space where the SM background is very small.

   hep-phEPJC(2021)·10 citations
4. 04*

   Current-component independent transition form factors for semileptonic and rare $D\to \pi (K)$ decays in the light-front quark model

   Ho-Meoyng Choi (Kyungpook National University)🇰🇷

   We investigate the exclusive semileptonic and rare $D\to \pi (K)$ decays within the standard model together with the light-front quark model (LFQM) constrained by the variational principle for the QCD-motivated effective Hamiltonian. The form factors are obtained in the $q^{+}=0$ frame and then analytically continue to the physical timelike region. Together with our recent analysis of the current-component independent form factors $f_{\pm }(q^2)$ for the semileptonic decays, we present the current-component independent tensor form factor $f_T(q^2)$ for the rare decays to make the complete set of hadronic matrix elements regulating the semileptonic and rare $D\to \pi (K)$ decays in our LFQM. The tensor form factor $f_T(q^2)$ are obtained from two independent sets $(J_T^{+\perp },J_T^{+-})$ of the tensor current $J_T^{\mu \nu }$. As in our recent analysis of $f_{-}(q^2)$, we show that $f_T(q^2)$ obtained from the two different sets of the current components gives the identical result in the valence region of the $q^{+}=0$ frame without involving the explicit zero modes and the instantaneous contributions. The implications of the zero modes and the instantaneous contributions are also discussed in comparison between the manifestly covariant model and the standard LFQM. In our numerical calculations, we obtain the $q^2$-dependent form factors $(f_{\pm },f_T)$ for $D\to \pi (K)$ and branching ratios for the semileptonic $D\to \pi (K)\ell {\nu }_{\ell }$ ($\ell =e,\mu$) decays. Our results show in good agreement with the available experimental data as well as other theoretical model predictions.

   hep-phAdv.High Energy Phys.(2021)·10 citations
5. 05*

   Bosonic fluctuations in the $(1+1)$-dimensional Gross-Neveu(-Yukawa) model at varying $\mu$ and $T$ and finite $N$

   Jonas Stoll🇩🇪 · Niklas Zorbach🇩🇪 · Adrian Koenigstein🇩🇪 · Martin J. Steil🇩🇪 · Stefan Rechenberger🇩🇪

   Using analogies between flow equations from the Functional Renormalization Group and flow equations from (numerical) fluid dynamics we investigate the effects of bosonic fluctuations in a bosonized Gross-Neveu model -- namely the Gross-Neveu-Yukawa model. We study this model for finite numbers of fermions at varying chemical potential and temperature in the local potential approximation. Thereby we numerically demonstrate that for any finite number of fermions and as long as the temperature is non-zero, there is no ${\mathbb{Z}}_2$ symmetry breaking for arbitrary chemical potentials.

   hep-phcond-mat.str-elnucl-th50 citations
6. 06*

   Ground state pseudoscalar mesons on the light front: from the light to heavy sector

   Chao Shi🇨🇳 · Ming Li🇨🇳 · Xurong Chen🇨🇳 · Wenbao Jia🇨🇳

   We extract the leading Fock-state light front wave functions (LF-LFWFs) of both the light and heavy pseudoscalar mesons, e.g., the pion (at masses of 130 MeV, 310 MeV and 690 MeV), ${\eta }_c$ and ${\eta }_b$, from their covariant Bethe-Salpeter wave functions within the rainbow-ladder (RL) truncation. It is shown that the LF-LFWFs get narrower in $x$ (the longitudinal momentum fraction of meson carried by the quark) with the increasing current quark mass, and the leading twist parton distribution amplitudes (PDAs) inherit this feature. Meanwhile, we find in the pion the LF-LFWFs only contribute around 30\% to the total Fock-state normalization, indicating the presence of significant higher Fock-states within. In contrast, in the ${\eta }_c$ and ${\eta }_b$ the LF-LFWFs contribute more than $90$\%, suggesting the $Q\bar{Q}$ valence Fock-state truncation as a good approximation for heavy mesons. We thus study the 3-dimensional parton distributions of the ${\eta }_c$ and ${\eta }_b$ with the unpolarized generalized parton distribution function (GPD) and the transverse momentum dependent parton distribution function (TMD). Through the gravitational form factors in connection with the GPD, the mass radii of the ${\eta }_c$ and ${\eta }_b$ in the light-cone frame are determined to be $r_{E,\mathrm{LC}}^{{\eta }_c}=0.150$ fm and $r_{E,\mathrm{LC}}^{{\eta }_b}=0.089$ fm respectively.

   hep-phPRD(2021)·14 citations
7. 07*

   Direct detection of pseudo-Nambu-Goldstone dark matter with light mediator

   Yoshihiko Abe🇯🇵 · Takashi Toma🇯🇵

   It has been found that a pseudo-Nambu-Goldstone boson dark matter suppresses the amplitude for elastic scattering with nuclei in non-relativistic limit, and thus can naturally evade the strong constraint of dark matter direct detection experiments. In this paper, we show that non-zero elastic scattering cross section can be induced if the mediator mass is as small as momentum transfer. The predicted recoil energy spectrum can differ from that for usual thermal dark matter. Together with the relevant constraints such as thermal relic abundance, indirect detection and Higgs decays, we investigate the detectability through the current and future dark matter direct detection experiments.

   hep-phPLB(2021)·15 citations
8. 08*

   Models of the Muonium to Antimuonium Transition

   Takeshi Fukuyama🇯🇵 · Yukihiro Mimura🇯🇵 · Yuichi Uesaka🇯🇵

   Muonium is a bound state composed of an antimuon and an electron, and it constitutes a hydrogen-like atom. Because of the absence of the hadronic matter in the bound state, the muonium is a useful probe to explore new physics being free from the hadronic uncertainties. The process of the muonium-to-antimuonium transition is considered to be effective to identify fundamental interactions which relate to the lepton flavor and lepton number violation. New experiments are being planned at J-PARC in Japan and CSNS in China, and it is expected to attract more attention in the near future. In this paper, we will study what kind of model can be verified in the next generation of the muonium-to-antimuonium transition search experiments while escaping the limitations from other experiments. Though the transition probability is strongly suppressed by the lepton flavor conservation in the standard model, it can be much larger by the exchanges of neutral and doubly charged bosons, and by box loop diagrams in new physics beyond the standard model. We study the neutrino models with heavy Majorana neutrinos at TeV scale, a type-II seesaw model, left--right models, and models for radiative neutrino masses such as the Zee-Babu model in particular, in addition to other possible models to induce the sizable transition probability, which can be tested in the forthcoming experiments.

   hep-phhep-exPRD(2022)·37 citations
9. 09*

   Can $\overline{MS}$ parton distributions be negative?

   Alessandro Candido🇮🇹 · Stefano Forte🇮🇹 · Felix Hekhorn🇮🇹

   We review our recent paper, where we proved Parton distributions functions (PDFs) to be positive at NLO in the $\overline{MS}$ factorization scheme. We present some additional material that was useful in completing the steps for the actual proof, but we won't attempt to report on the full proof, but referring the reader to the paper itself.

   hep-phSciPost Phys.Proc.(2022)·0 citations
10. 10*

    Cosmic-ray antiproton excess from annihilating tensor dark matter

    H. Hernández-Arellano🇲🇽 · M. Napsuciale🇲🇽 · S. Rodríguez🇲🇽 · R. Ramírez-Cruz

    In this paper we calculate the antiproton production in the annihilation of tensor dark matter and explore the possibility that the excess of antiprotons in the range $E_K=10-20GeV$ reported by several groups in the analysis of the AMS-02 Collaboration data is due to this production mechanism. We find that these contributions improve the fit to the data on the antiproton to proton ratio for the narrow window $M\in [62.470,62.505]\text{ GeV}$ for the tensor dark matter mass and $g_s\in [0.98,1.01]\times 10^{-3}$ for the Higgs portal coupling in the effective theory. These are precisely the range of values compatible with several experimental constraints, such as dark matter relic density, limits on the spin-independent dark matter-nucleon cross-section from XENON1T, indirect detection limits for the annihilation of dark matter into $\bar{b}b$, ${\tau }^{+}{\tau }^{-}$, ${\mu }^{+}{\mu }^{-}$ and $\gamma \gamma$, as well as with the gamma-ray excess at the Milky Way galactic center.

    hep-phastro-ph.HE3 citations
11. 11*

    Interleaved Resonance Decays and Electroweak Radiation in Vincia

    Helen Brooks🇦🇺 · Peter Skands🇦🇺 · Rob Verheyen🇬🇧

    We propose a framework for high-energy interactions in which resonance decays and electroweak branching processes are interleaved with the QCD evolution in a single common sequence of decreasing resolution scales. The interleaved treatment of resonance decays allows for a new treatment of finite-width effects in parton showers. At scales above their offshellness, resonances participate explicitly as incoming and outgoing states in branching processes, while they are effectively "integrated out" of the description at lower scales. We implement this formalism, together with a full set of antenna functions for branching processes involving electroweak (W/Z/H) bosons in the Vincia shower module in Pythia 8.3, and study some of the consequences.

    hep-phSciPost Phys.(2022)·31 citations
12. 12*

    Expansion by regions with pySecDec

    G. Heinrich🇩🇪 · S. Jahn🇩🇪 · S.P. Jones🇬🇧 · M. Kerner🇨🇭 · F. Langer🇩🇪 · V. Magerya🇩🇪 · A. Poldaru🇩🇪 · J. Schlenk🇨🇭 · E. Villa🇩🇪

    We discuss the technique of expansion by regions from a geometric perspective, and its implementation within pySecDec, a toolbox for the evaluation of dimensionally regulated parameter integrals. The program offers an automated way to perform asymptotic expansions and provides a new mechanism for efficiently evaluating amplitudes, as well as individual integrals. The usage of the new features available within pySecDec is illustrated with several examples.

    hep-phComput.Phys.Commun.(2022)·106 citations
13. 13*

    Implementation of Angularly Ordered Electroweak Parton Shower in Herwig 7

    M.R. Masouminia🇬🇧 · P. Richardson🇬🇧

    We discuss the necessary steps for implementing an angularly ordered (AO) electroweak (EW) parton shower in Herwig 7 multi-purpose event generator. This includes calculating the helicity-dependent quasi-collinear EW branching functions that correspond to the full range of final-state EW parton shower, in addition to the initial-state EW gauge vector boson radiations. The results are successfully embedded in the AO Herwig 7 shower algorithm and have undergone a set of comprehensive and conclusive performance tests. Furthermore, we have used this EW parton shower algorithm, alongside the existing $QCD+QED$ AO shower, to predict the angular distributions of $W^{\pm }$ bosons in LHC events with high transverse momentum jets. These results are compared against the explicitly generated underlying events as well as the existing ATLAS data to show the effectiveness of the newly implemented $QCD+QED+EW$ AO parton shower scheme.

    hep-phJHEP(2022)·34 citations
14. 14*

    Reconciling Higgs physics and pseudo-Nambu-Goldstone dark matter in the S2HDM using a genetic algorithm

    Thomas Biekötter🇩🇪 · María Olalla Olea🇩🇪

    We investigate a possible realization of pseudo-Nambu-Goldstone (pNG) dark matter in the framework of a singlet-extended 2 Higgs doublet model (S2HDM). pNG dark matter gained attraction due to the fact that direct-detection constraints can be avoided naturally because of the momentum-suppressed scattering cross sections, whereas the relic abundance of dark matter can nevertheless be accounted for via the usual thermal freeze-out mechanism. We confront the S2HDM with a multitude of theoretical and experimental constraints, paying special attention to the theoretical limitations on the scalar potential, such as vacuum stability and perturbativity. In addition, we discuss the complementarity between constraints related to the dark matter sector, on the one hand, and to the Higgs sector, on the other hand. In our numerical discussion we explore the Higgs funnel region with dark matter masses around $60$GeV using a genetic algorithm. We demonstrate that the S2HDM can account for the measured relic abundance while being in agreement with all relevant constraints. We also discuss whether the so-called galactic center excess and the antiproton excess can be accommodated, possibly in combination with a Higgs boson at about $96$GeV that can be the origin of the LEP- and the CMS-excess observed at this mass in the $b\bar{b}$-quark and the diphoton final state, respectively.

    hep-phJHEP(2021)·77 citations
15. 15*

    Higher fidelity simulations of nonlinear Breit-Wheeler pair creation in intense laser pulses

    T. G. Blackburn🇸🇪 · B. King🇬🇧

    When a photon collides with a laser pulse, an electron-positron pair can be produced via the nonlinear Breit-Wheeler process. A simulation framework has been developed to calculate this process, which is based on a ponderomotive approach that includes strong-field quantum electrodynamical effects via the locally monochromatic approximation (LMA). Here we compare simulation predictions for a variety of observables, in different physical regimes, with numerical evaluation of exact analytical results from theory. For the case of a focussed laser background, we also compare simulation with a high-energy theory approximation. These comparisons are used to quantify the accuracy of the simulation approach in calculating harmonic structure, which appears in the lightfront momentum and angular spectra of outgoing particles, and the transition from multi-photon to all-order pair creation. Calculation of the total yield of pairs over a range of intensity parameters is also used to assess the accuracy of the locally constant field approximation (LCFA).

    hep-phphysics.plasm-phEPJC(2022)·44 citations
16. 16*

    Accelerating Composite Dark Matter Discovery with Nuclear Recoils and the Migdal Effect

    Javier F. Acevedo🇨🇦 · Joseph Bramante🇨🇦 · Alan Goodman🇨🇦

    Large composite dark matter states source a scalar binding field that, when coupled to Standard Model nucleons, provides a potential under which nuclei recoil and accelerate to energies capable of ionization, radiation, and thermonuclear reactions. We show that these dynamics are detectable for nucleon couplings as small as $g_n\sim 10^{-17}$ at dark matter experiments, where the greatest sensitivity is attained by considering the Migdal effect. We also explore Type-Ia supernovae and planetary heating as possible means to discover this type of dark matter.

    hep-phastro-ph.HEhep-exPRD(2022)·55 citations
17. 17*

    Positivity and Geometric Function Theory Constraints on Pion Scattering

    Ahmadullah Zahed🇮🇳

    This paper presents the fascinating correspondence between the geometric function theory and the scattering amplitudes with $O(N)$ global symmetry. A crucial ingredient to show such correspondence is a fully crossing symmetric dispersion relation in the $z$-variable, rather than the fixed channel dispersion relation. We have written down fully crossing symmetric dispersion relation for $O(N)$ model in $z$-variable for three independent combinations of isospin amplitudes. We have presented three independent sum rules or locality constraints for the $O(N)$ model arising from the fully crossing symmetric dispersion relations. We have derived three sets of positivity conditions. We have obtained two-sided bounds on Taylor coefficients of physical Pion amplitudes around the crossing symmetric point (for example, ${\pi }^{+}{\pi }^{-}\to {\pi }^0{\pi }^0$) applying the positivity conditions and the Bieberbach-Rogosinski inequalities from geometric function theory.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2021)·40 citations
18. 18*

    On the narrow spectral feature at $\sim$3 TeV in the MAGIC spectrum of Mrk 501

    Wen Hu🇨🇳 · DaHai Yan🇨🇳

    Using a time-dependent one-zone leptonic model that incorporates both shock acceleration and stochastic acceleration processes, we investigate the formation of the narrow spectral feature at $\sim 3$ TeV of Mrk 501 which was observed during the X-ray and TeV flaring activity in July 2014. It is found that the broadband spectral energy distribution (SED) can be well interpreted as the synchrotron and synchrotron-self-Compton emission from the electron energy distribution (EED) that is composed by a power-law (PL) branch and a pileup branch. The PL branch produces synchrotron photons which are scattered by the electrons of the pileup branch via inverse-Compton scattering and form the narrow spectral feature observed at the TeV energies. The EED is produced by two injection episodes, and the pileup branch in EED is caused by shock acceleration rather than stochastic acceleration.

    ↳ astro-ph.HEhep-phMNRAS(2021)·8 citations
19. 19*

    Constraining the Polarization of Gravitational Waves with the Parkes Pulsar Timing Array Second Data Release

    Yu-Mei Wu🇨🇳 · Zu-Cheng Chen🇨🇳 · Qing-Guo Huang🇨🇳

    We search for the isotropic stochastic gravitational-wave background, including the nontensorial polarizations that are allowed in general metric theories of gravity, in the Parkes Pulsar Timing Array (PPTA) second data release (DR2). We find no statistically significant evidence that the common-spectrum process reported by the PPTA collaboration has the tensor transverse, scalar transverse, vector longitudinal, or scalar longitudinal correlations in PPTA DR2. Therefore, we place a $95\%$ upper limit on the amplitude of each polarization mode, as ${\mathcal{A}}_{\mathrm{TT}}\lesssim 3.2\times 10^{-15}$, ${\mathcal{A}}_{\mathrm{ST}}\lesssim 1.8\times 10^{-15}$, ${\mathcal{A}}_{\mathrm{VL}}\lesssim 3.5\times 10^{-16}$ and ${\mathcal{A}}_{\mathrm{SL}}\lesssim 4.2\times 10^{-17}$; or, equivalently, a $95\%$ upper limit on the energy density parameter per logarithm frequency, as ${\Omega }_{\mathrm{GW}}^{\mathrm{TT}}\lesssim 1.4\times 10^{-8}$, ${\Omega }_{\mathrm{GW}}^{\mathrm{ST}}\lesssim 4.5\times 10^{-9}$, ${\Omega }_{\mathrm{GW}}^{\mathrm{VL}}\lesssim 1.7\times 10^{-10}$ and ${\Omega }_{\mathrm{GW}}^{\mathrm{SL}}\lesssim 2.4\times 10^{-12}$, at a frequency of 1/yr.

    ↳ astro-ph.COgr-qchep-phhep-thApJ(2022)·54 citations
20. 20*

    Tachyonic Preheating in Plateau Inflation

    Eemeli Tomberg🇪🇪 · Hardi Veermäe🇪🇪

    Plateau inflation is an experimentally consistent framework in which the scale of inflation can be kept relatively low. Close to the edge of the plateau, scalar perturbations are subject to a strong tachyonic instability. Tachyonic preheating is realized when, after inflation, the oscillating inflaton repeatedly re-enters the plateau. We develop the analytic theory of this process and expand the linear approach by including backreaction between the coherent background and growing perturbations. For a family of plateau models, the analytic predictions are confronted with numerical estimates. Our analysis shows that the inflaton fragments in a fraction of an $e$-fold in all examples supporting tachyonic preheating, generalizing the results of previous similar studies. In these scenarios, the scalar-to-tensor ratio is tiny, $r<10^{-7}$.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2021)·25 citations
21. 21*

    Transversity GPDs of the proton from lattice QCD

    Constantia Alexandrou🇨🇾 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Kyriakos Hadjiyiannakou🇨🇾 · Karl Jansen🇩🇪 · Aurora Scapellato🇺🇸 · Fernanda Steffens🇩🇪

    We present the first calculation of the $x$-dependence of the isovector transversity generalized parton distributions (GPDs) for the proton within lattice QCD. We compute the matrix elements with non-local operators containing a Wilson line. The calculation implements the Breit symmetric frame. The proton momenta are chosen as $0.83,1.25,1.67$ GeV, and the values of the momentum transfer squared are $0.69,1.02$ GeV${}^2$. These combinations include cases with zero and nonzero skewness. The calculation is performed using one ensemble of two degenerate-mass light, a strange and a charm quark of maximally twisted mass fermions with a clover term. The lattice results are renormalized non-perturbatively and finally matched to the light-cone GPDs using one-loop perturbation theory within the framework of large momentum effective theory. The final GPDs are given in the $\overline{\mathrm{MS}}$ scheme at a scale of 2 GeV. In addition to the individual GPDs, we form the combination of the transversity GPDs that is related to the transverse spin structure of the proton. Finally, we extract the lowest two moments of GPDs and draw a number of important qualitative conclusions.

    ↳ hep-lathep-exhep-phhep-th+1PRD(2022)·82 citations
22. 22*

    Bosonic field digitization for quantum computers

    Alexandru Macridin🇺🇸 · Andy C. Y. Li🇺🇸 · Stephen Mrenna🇺🇸 · Panagiotis Spentzouris🇺🇸

    Quantum simulation of quantum field theory is a flagship application of quantum computers that promises to deliver capabilities beyond classical computing. The realization of quantum advantage will require methods to accurately predict error scaling as a function of the resolution and parameters of the model that can be implemented efficiently on quantum hardware. In this paper, we address the representation of lattice bosonic fields in a discretized field amplitude basis, develop methods to predict error scaling, and present efficient qubit implementation strategies. A low-energy subspace of the bosonic Hilbert space, defined by a boson occupation cutoff, can be represented with exponentially good accuracy by a low-energy subspace of a finite size Hilbert space. The finite representation construction and the associated errors are directly related to the accuracy of the Nyquist-Shannon sampling and the Finite Fourier transforms of the boson number states in the field and the conjugate-field bases. We analyze the relation between the boson mass, the discretization parameters used for wavefunction sampling and the finite representation size. Numerical simulations of small size ${\Phi }^4$ problems demonstrate that the boson mass optimizing the sampling of the ground state wavefunction is a good approximation to the optimal boson mass yielding the minimum low-energy subspace size. However, we find that accurate sampling of general wavefunctions does not necessarily result in accurate representation. We develop methods for validating and adjusting the discretization parameters to achieve more accurate simulations.

    ↳ quant-phcond-mat.str-elhep-phPRA(2022)·35 citations
23. 23*

    A variational study of two-nucleon systems with lattice QCD

    Saman Amarasinghe🇺🇸 · Riyadh Baghdadi🇺🇸 · Zohreh Davoudi🇺🇸 · William Detmold🇺🇸 · Marc Illa🇪🇸 · Assumpta Parreno🇪🇸 · Andrew V. Pochinsky🇺🇸 · Phiala E. Shanahan🇺🇸 · Michael L. Wagman🇺🇸

    The low-energy spectrum and scattering of two-nucleon systems are studied with lattice quantum chromodynamics using a variational approach. A wide range of interpolating operators are used: dibaryon operators built from products of plane-wave nucleons, hexaquark operators built from six localized quarks, and quasi-local operators inspired by two-nucleon bound-state wavefunctions in low-energy effective theories. Sparsening techniques are used to compute the timeslice-to-all quark propagators required to form correlation-function matrices using products of these operators. Projection of these matrices onto irreducible representations of the cubic group, including spin-orbit coupling, is detailed. Variational methods are applied to constrain the low-energy spectra of two-nucleon systems in a single finite volume with quark masses corresponding to a pion mass of 806 MeV. Results for S- and D-wave phase shifts in the isospin singlet and triplet channels are obtained under the assumption that partial-wave mixing is negligible. Tests of interpolating-operator dependence are used to investigate the reliability of the energy spectra obtained and highlight both the strengths and weaknesses of variational methods. These studies and comparisons to previous studies using the same gauge-field ensemble demonstrate that interpolating-operator dependence can lead to significant effects on the two-nucleon energy spectra obtained using both variational and non-variational methods, including missing energy levels and other discrepancies. While this study is inconclusive regarding the presence of two-nucleon bound states at this quark mass, it provides robust upper bounds on two-nucleon energy levels that can be improved in future calculations using additional interpolating operators and is therefore a step toward reliable nuclear spectroscopy from the underlying Standard Model of particle physics.

    ↳ hep-lathep-phnucl-thPRD(2023)·93 citations
24. 24*

    Holographic drag force in non-conformal plasma

    Tolga Domurcukgul🇹🇷 · Razieh Morad🇹🇷

    In this study, the gauge/string duality is used to investigate the dynamics of a moving heavy quark in a strongly coupled, non-conformal plasma. The drag force in this non-conformal model is smaller than that of $\mathcal{N}=4$ supersymmetric Yang-Mills (SYM) plasma and decreases as the level of non-conformality is increased. At intermediate temperatures, the world-sheet temperature, which is derived numerically by calculating the world-sheet horizon, deviates from its conformal value, but at high temperatures, it tends to its conformal value.

    ↳ hep-thhep-phEPJC(2022)·4 citations
25. 25*

    On the primordial correlation of gravitons with gauge fields

    Rajeev Kumar Jain🇮🇳 · P. Jishnu Sai🇮🇳 · Martin S. Sloth🇩🇰

    We calculate the primordial correlation of gravitons with an abelian gauge field non-minimally coupled through a dynamical dilaton field or a volume moduli during inflation in the early universe. In particular, we compute the cross-correlation of a tensor mode with two gauge field modes and the corresponding correlation functions for the associated magnetic and electric fields using the in-in formalism. Moreover, using semi-classical methods, we show that the three-point cross-correlation functions satisfy new consistency relations (soft theorems) in the squeezed limit. Our findings exhibit a complete agreement of the full in-in results with the new consistency relations. An interesting consequence of our scenario is the possibility of a novel correlation of the primordial tensor mode with the primordial curvature perturbation induced by higher order quantum gravity corrections. The anisotropic background created by long wavelength gauge field modes makes this correlation function non-vanishing. Finally, we discuss how these three-point correlation functions are imprinted on cosmological observables today and the applications to scenarios of inflationary magnetogenesis.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2022)·5 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.