Thu·Feb 28, 2019Thursday·February 28, 2019

1. 01*

   Electromagnetic multipole moments of baryons

   Alfons J. Buchmann🇩🇪

   We calculate the charge quadrupole and magnetic octupole moments of baryons using a group theoretical approach based on broken SU(6) spin-flavor symmetry. The latter is an approximate symmetry of the QCD Lagrangian which becomes exact in the large color N_c limit. Spin-flavor symmetry breaking is induced by one-, two-, and three-quark terms in the electromagnetic current operator. Two- and three-quark currents provide the leading contributions for higher multipole moments, despite being of higher order in an 1/N_c expansion. Our formalism leads to relations between N --> N* transition multipole moments and nucleon ground state properties. We compare our results to experimental quadrupole and octupole transition moments extracted from measured helicity amplitudes.

   hep-phnucl-thFew Body Syst.(2018)·9 citations
2. 02*

   One-loop weak corrections to Higgs production

   Valentin Hirschi🇨🇭 · Simone Lionetti🇬🇧 · Armin Schweitzer🇨🇭

   We compute mixed QCD-weak corrections to inclusive Higgs production at the LHC from the partonic process $gg\to Hq\bar{q}$. We start from the UV- and IR-finite one-loop weak amplitude and consider its interference with the corresponding one-loop QCD amplitude. This contribution is a $\mathcal{O}({\alpha }_s\alpha )$ correction to the leading-order gluon-fusion cross section, and was not numerically assessed in previous works. We also compute the cross section from the square of this weak amplitude, suppressed by $\mathcal{O}({\alpha }^2)$. Finally, we consider contributions from the partonic process $gq\to Hq$, which are one order lower in ${\alpha }_s$, as a reference for the size of terms which are not enhanced by the large gluon luminosity. We find that, given the magnitude of the uncertainties on current state-of-the-art predictions for Higgs production, all contributions computed in this work can be safely ignored, both fully inclusively and in the boosted Higgs regime. This result supports the approximate factorisation of QCD and weak corrections to that process.

   hep-phJHEP(2019)·13 citations
3. 03*

   New Constraints on Xenonphobic Dark Matter from DEAP-3600

   Carlos E. Yaguna🇨🇴

   The first-year results from DEAP-3600, a single-phase liquid argon direct-detection dark matter experiment, were recently reported. At first sight, they seem to provide no new constraints, as the limit lies well within the region already excluded by three different xenon experiments: LUX, PandaX-II, and XENON1T. We point out, however, that this conclusion is not necessarily true, for it is based on the untested assumption that the dark matter particle couples equally to protons and neutrons. For the more general case of isosping-violating dark matter, we find that there are regions in the parameter space where DEAP-3600 actually provides the most stringent limits on the dark matter-proton spin-independent cross section. Such regions correspond to the so-called Xenonphobic dark matter scenario, for which the neutron-to-proton coupling ratio is close to $-0.7$. Our results seem to signal the beginning of a new era in which the complementarity among different direct detection targets will play a crucial role in the determination of the fundamental properties of the dark matter particle.

   hep-phJCAP(2019)·12 citations
4. 04*

   Constraining dimension-six nonminimal Lorentz-violating electron-nucleon interactions with EDM physics

   Jonas B. Araujo🇧🇷 · A. H. Blin🇵🇹 · Marcos Sampaio🇧🇷 · Manoel M. Ferreira Jr🇧🇷

   The electric dipole moment (EDM) of an atom could arise also from $P$-odd and $T$-odd electron-nucleon couplings. In this work we investigate a general class of dimension-$6$ electron-nucleon ($e$-$N$) nonminimal interactions mediated by Lorentz-violating (LV) tensors of rank ranging from $1$ to $4$. The possible couplings are listed as well as their behavior under $C$, $P$ and $T$, allowing us to select the couplings compatible with EDM physics. The unsuppressed contributions of these couplings to the atom's Hamiltonian can be read as EDM-equivalent. The LV coefficients' magnitudes are limited using EDM experimental data to the level of $3.2\times 10^{-13}{\text{(GeV)}}^{-2}$ or $1.6\times 10^{-15}{\text{(GeV)}}^{-2}$.

   hep-phPRD(2019)·10 citations
5. 05*

   CP-violating Dark Photon Interaction

   Kaori Fuyuto🇺🇸 · Xiao-Gang He🇹🇼 · Gang Li🇹🇼 · Michael Ramsey-Musolf🇺🇸

   We introduce a scenario for CP-violating (CPV) dark photon interactions in the context of non-abelian kinetic mixing. Assuming an effective field theory that extends the Standard Model (SM) field content with an additional $U(1)$ gauge boson ($X$) and a $SU(2{)}_L$ triplet scalar, we show that there exist both CP-conserving and CPV dimension five operators involving these new degrees of freedom and the SM $SU(2{)}_L$ gauge bosons. The former yields kinetic mixing between the $X$ and the neutral $SU(2{)}_L$ gauge boson (yielding the dark photon), while the latter induces CPV interactions of the dark photon with the SM particles. We discuss experimental probes of these interactions using searches for permanent electric dipole moments (EDMs) and di-jet correlations in high-energy $pp$ collisions. It is found that the experimental limit on the electron EDM currently gives the strongest restriction on the CPV interaction. In principle, high energy $pp$ collisions provide a complementary probe through azimuthal angular correlations of the two forward tagging jets in vector boson fusion. In practice, observation of the associated CPV asymmetry is likely to be challenging.

   hep-phPRD(2020)·28 citations
6. 06*

   Reduction of Feynman Integrals in the Parametric Representation

   Wen Chen🇨🇦

   In this paper, the reduction of Feynman integrals in the parametric representation is considered. This method proves to be more efficient than the integration-by-part (IBP) method in the momentum space. Tensor integrals can directly be parametrized without performing tensor reductions. The integrands of parametric integrals are functions of Lorentz scalars, instead of four momenta. The complexity of a calculation is determined by the number of propagators that are present rather than the number of all the linearly independent propagators. Furthermore, the symmetries of Feynman integrals under permutations of indices are transparent in the parametric representation. Since all the indices of the propagators are nonnegative, an algorithm to solve those identities can easily be developed, which can be used for automatic calculations.

   hep-phJHEP(2020)·28 citations
7. 07*

   Scalar-involved three-point Green functions and their phenomenology

   Ling-Yun Dai🇨🇳 · Javier Fuentes-Martin🇨🇭 · Jorge Portoles🇪🇸

   We analyse within the framework of resonance chiral theory the $⟨S{A}_{\mu }{A}_{\nu }⟩$ and $⟨S{V}_{\mu }{V}_{\nu }⟩$ three-point Green functions, where $S$, $A_{\mu }$ and $V_{\mu }$ are short for scalar, axial-vector and vector $SU(3)$ hadronic currents. We construct the necessary Lagrangian such that the Green functions fulfill the asymptotic constraints, at large momenta, imposed by QCD at leading order. We study the implications of our results on the spectrum of scalars in the large-$N_C$ limit, and analyse their decays.

   hep-phPRD(2019)·27 citations
8. 08*

   Aspects of quarkonium propagation in a thermal medium as seen by string models

   Oleg Andreev🇷🇺

   We use gauge/string duality to model a heavy quark-antiquark pair in a color singlet moving through a thermal plasma. In particular, we explore the effect of velocity on the string tension and Debye screening mass. Then we apply the results to the analysis of heavy quarkonium bound states. With some assumptions, we estimate the characteristic size of quarkonium and its dissociation temperature.

   hep-phhep-lathep-thnucl-thPRD(2019)·4 citations
9. 09*

   Searching for Axino-Like Particle at Fixed Target Experiments

   Ki-Young Choi🇰🇷 · Takeo Inami🇰🇷 · Kenji Kadota🇰🇷 · Inwoo Park🇰🇷 · Osamu Seto🇯🇵

   We investigate the detectability of axino-like particle, which is defined as a supersymmetric partner of axion-like particle and can be a good candidate for dark matter in our Universe. Especially, we consider the fixed target experiments to search for the light axino-like particle with a neutralino as the next-to-lightest supersymmetric particle. We calculate the production and decay rate of neutralinos and the consequent number of events (such as photons and charged leptons) that are produced when the neutralinos decay to the axino-like particles.

   hep-phastro-ph.COPhys.Dark Univ.(2020)·12 citations
10. 10*

    Flavor decomposition of the pion-nucleon $\sigma$-term

    Daniel Severt🇩🇪 · Ulf-G. Meißner🇩🇪 · Jambul Gegelia🇬🇪

    We re-analyze the flavor decomposition of the pion-nucleon $\sigma$-term in the framework of baryon chiral perturbation to fourth order. We employ a covariant and the heavy baryon framework including also the low-lying decuplet. Using only continuum data, we find a small strangeness content of the proton. The uncertainties are, however, large and might be overcome by dedicated lattice QCD calculations.

    hep-phhep-latnucl-thJHEP(2019)·12 citations
11. 11*

    Monte Carlo sampling variant of the DSSV14 set of helicity parton densities

    Daniel de Florian🇦🇷 · Gonzalo Agustin Lucero🇦🇷 · Rodolfo Sassot🇦🇷 · Marco Stratmann🇩🇪 · Werner Vogelsang🇩🇪

    We implement a Monte Carlo sampling strategy to extract helicity parton densities and their uncertainties from a reference set of longitudinally polarized scattering data, chosen to be that used in the DSSV14 global analysis. Instead of adopting the simplest possible functional forms for the helicity parton distributions and imposing certain restrictions on their parameter space in order to constrain them, we employ redundant, flexible parametrizations and fit them to a large number of Monte Carlo replicas of the existing data. The optimum fit and its uncertainty estimates are then assumed to be given by the statistical average of the obtained ensemble of replicas of helicity parton densities and their corresponding variance, respectively. We compare our results to those obtained by the traditional fitting approach and to the uncertainty estimates derived with the robust Lagrange multiplier method, finding good agreement. As a first application of our new set of replicas, we discuss the impact of the recent STAR dijet data in further constraining the elusive gluon helicity density through the reweighting method.

    hep-phhep-exPRD(2019)·101 citations
12. 12*

    Semi-inclusive Deep-Inelastic Scattering, Parton Distributions and Fragmentation Functions at a Future Electron-Ion Collider

    Elke C. Aschenauer🇺🇸 · Ignacio Borsa🇦🇷 · Rodolfo Sassot🇦🇷 · Charlotte Van Hulse🇮🇪

    We present a quantitative assessment of the impact a future Electron-Ion Collider would have in the determination of parton distribution functions in the proton and parton-to-hadron fragmentation functions through semi-inclusive deep-inelastic electron-proton scattering data. Specifically, we estimate the kinematic configurations for which the forthcoming data are expected to have the most significant impact in the precision of these distributions, computing the respective correlation and sensitivity coefficients. Implementing the reweighting technique over sets of simulated data with realistic uncertainties for two different center-of-mass energies, we analyse the resulting upgraded sets of PDFs and FFs, which have significantly reduced uncertainties.

    hep-phhep-exPRD(2019)·61 citations
13. 13*

    Chiral imbalance in hadron matter : its manifestation in photon polarization asymmetries

    A.A.Andrianov🇷🇺 · V.A.Andrianov🇷🇺 · D.Espriu🇪🇸 · A.V.Iakubovich🇷🇺 · A.E.Putilova🇷🇺

    The possibility of the formation of a local parity breaking (LPB) in a quark-hadron medium is examined as a result of chiral symmetry violation, i.e, the appearance of difference between the average densities of right- and left-handed quarks in the fireball after heavy-ion collisions (HIC). Using the effective meson Lagrangian motivated by QCD extended to the chiral medium the properties of light scalar and pseudoscalar mesons are analyzed. It is establish that exotic decays of scalar mesons arise due to mixing of $\pi$ and $a_0$ vacuum states in the presence of chiral imbalance. The pion electromagnetic formfactor obtains a parity-odd supplement which generates a photon polarization asymmetry in pion polarizability. We conjecture that the above-mentioned properties of LPB can be revealed in experiments on LHC, RHIC, FAIR and NICA accelerators.

    hep-phnucl-thPhys.Part.Nucl.Lett.(2019)·3 citations
14. 14*

    Comment on "Monopole production via photon fusion and Drell-Yan processes: MadGraph implementation and perturbativity via velocity-dependent coupling and magnetic moment as novel features"

    Ricardo Heras🇬🇧

    In a recent study on monopole production [Eur. Phys. J. C (2018) 78: 966], Baines et al added the potential of a magnetic dipole to the Wu-Yang potentials for the Dirac monopole and claimed that this modified Wu-Yang configuration does not affect the Dirac quantisation condition. In this comment, we argue that their claim is incorrect by showing that their modified Wu-Yang configuration leads to an infinite number of quantisation conditions. In their study, they also incorrectly identified the magnetic field of the monopole with the magnetic field of the Dirac string and its attached magnetic monopole.

    hep-phhep-thphysics.class-ph1 citation
15. 15*

    Decay of the pseudoscalar glueball and its first excited state into scalar and pseudoscalar mesons and their first excited states

    Walaa I. Eshraim🇩🇪

    We expand the study of the pseudoscalar glueball and its first excited state by constructing an interaction Lagrangian which produces the two- and three-body decays of the pseudoscalar glueball, $J^{PC}=0^{-+}$, into the (pseudo)scalar and the excited (pseudo)scalar mesons as well as by constructing other two different chiral Lagrangians which describe the two- and three-body decays of the first excited pseudoscalar glueball, $J^{PC}=0^{\ast -+}$, into the (pseudo)scalar and the excited (pseudo)scalar mesons. We compute the decay channels for the ground state of a pseudoscalar glueball with a mass of $2.6$ GeV and for the first excited pseudoscalar glueball with a mass $3.7$ GeV, following predictions from Lattice QCD in the quenched approximation. These states and channels are within reach of PANDA experiment at the upcoming FAIR facility experiment and ongoing BESIII experiment. In our approach, the various branching ratios are a parameter-free prediction.

    hep-phPRD(2019)·13 citations
16. 16*

    Report on the Physics at the HL-LHC and Perspectives for the HE-LHC

    ATLAS · CMS Collaborations

    Manuscript of volume 2 of the Yellow Report on the "Workshop on the Physics of HL-LHC and perspectives at HE-LHC" containing the notes produced by the ATLAS and CMS collaborations as input to the Yellow Report volume 1.

    ↳ hep-exhep-phCERN Yellow Rep.Monogr.(2019)·137 citations
17. 17*

    Constraints on Disconnected Contributions in $\pi \pi$ Scattering

    N. Ripunjay Acharya🇩🇪 · Feng-Kun Guo🇨🇳 · Ulf-G. Meißner🇩🇪 · Chien-Yeah Seng🇩🇪

    The accuracy of the lattice QCD computation of hadron-hadron scattering at low isospin depends critically on the ability to compute correlation functions with fermionic disconnected Wick contractions. This happens, for instance, in isospin $I=0$ $\pi \pi$ scattering, which receives contributions from rectangular and vacuum types of contractions among other easier calculable ones. Combining Lüscher's formula and partially-quenched chiral perturbation theory, we provide precise theory predictions of the discrete energy levels extracted from specific linear combinations of lattice correlation functions corresponding to various types of contractions. Expressions are provided for extracting the unphysical low-energy constants in the partially-quenched chiral perturbation theory from the energy levels for these contractions. The predictions for the rectangular and vacuum contractions may serve as solid tests of the accuracy for existing and future lattice studies of $\pi \pi$ scattering.

    ↳ hep-lathep-phnucl-thJHEP(2019)·6 citations
18. 18*

    No anomalous canonical commutators induced by Berry's phase

    Shinichi Deguchi🇯🇵 · Kazuo Fujikawa🇯🇵

    The monopole-like singularity of Berry's adiabatic phase in momentum space and associated anomalous Poisson brackets have been recently discussed in various fields. With the help of the results of an exactly solvable version of Berry's model, we show that Berry's phase does not lead to the deformation of the principle of quantum mechanics in the sense of anomalous canonical commutators. If one should assume Berry's phase of genuine Dirac monopole-type, which is assumed to hold not only in the adiabatic limit but also in the non-adiabatic limit, the deformation of the principle of quantum mechanics could take place. But Berry's phase of the genuine Dirac monopole-type is not supported by the exactly solvable version of Berry's model nor by a generic model of Berry's phase. Besides, the monopole-like Berry's phase in momentum space has a magnetic charge $e_M=2\pi \hslash$, for which the possible anomalous term in the canonical commutator $[x_k,x_l]=i\hslash {\Omega }_{kl}$ would become of the order $O({\hslash }^2)$.

    ↳ hep-thcond-mat.mes-hallhep-phAnnals Phys.(2020)·6 citations
19. 19*

    The quenched SU(2) scalar-gluon vertex in minimal Landau gauge

    Axel Maas🇦🇹

    The question of whether confining effects are visible in correlation functions is a long-standing one. Complementing investigations on the propagators of fundamental and adjoint scalar matter particles here the quenched scalar-gluon vertex is investigated. For this purpose a multitude of lattice setups in two, three, and four dimensions is analyzed in quenched SU(2) lattice gauge theory. Though both cases are quantitatively different, neither a qualitative difference nor any singularities are observed.

    ↳ hep-lathep-phPRD(2019)·3 citations
20. 20*

    Static two-body potential at fifth post-Newtonian order

    Stefano Foffa🇨🇭 · Pierpaolo Mastrolia🇮🇹 · Riccardo Sturani🇧🇷 · Christian Sturm🇩🇪 · William J. Torres Bobadilla🇪🇸

    We determine the gravitational interaction between two compact bodies up to the sixth power in Newton's constant GN, in the static limit. This result is achieved within the effective field theory approach to General Relativity, and exploits a manifest factorization property of static diagrams which allows to derive static post Newtonian (PN) contributions of (2n+1)-order in terms of lower order ones. We recompute in this fashion the 1PN and 3PN static potential, and present the novel 5PN contribution.

    ↳ gr-qchep-phhep-thPRL(2019)·145 citations
21. 21*

    The phenomenology of beyond Horndeski gravity

    Dina Traykova🇬🇧 · Emilio Bellini🇬🇧 · Pedro G. Ferreira🇬🇧

    We study the phenomenology of the beyond Horndeski class of scalar-tensor theories of gravity, which on cosmological scales can be characterised in terms of one extra function of time, ${\alpha }_{\mathrm{H}}$, as well as the usual four Horndeski set of free functions. We show that ${\alpha }_{\mathrm{H}}$ can be directly related to the the damping of the matter power spectrum on both large and small scales. We also find that the temperature power spectrum of the cosmic microwave background (CMB) is enhanced at low multipoles and the lensing potential is decreased, as a function of ${\alpha }_{\mathrm{H}}$. We find constraints on ${\alpha }_{\mathrm{H}}$ of order $\mathcal{O}(1)$ using measurements of the temperature and polarisation of the CMB, as well as the lensing potential derived from it, combined with large scale structure data. We find that redshift space distortion measurements can play a significant role in constraining these theories. Finally, we comment on the recent constraints from the observation of an electromagnetic counterpart to a gravitational wave signal; we find that these constraints reduce the number of free parameters of the model but do not significantly change the constraints on the remaining parameters.

    ↳ astro-ph.COgr-qchep-phJCAP(2019)·30 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.