Thu·Nov 19, 2015Thursday·November 19, 2015

1. 01*

   Quantum Cherenkov radiation by spinless and spin-1/2 particles

   Stanislav Iablokov🇷🇺

   In this paper, the Cherenkov radiation process is investigated in the frame of the Quantum Field Theory, both for the spinless and spin-1/2 charged particles. In the latter case, the polarization density matrix technique was used to account for the spin flip. If compared with the Classical Electrodynamics results, in both cases several quantum corrections arise, coinciding up to the photon's energy linear term. It is shown that, while the absolute value of these corrections significantly relies on the refractive index, the relative quantum correction stays independent of the medium in the case of the ultrarelativistic particles. It the case of the spin-1/2 particles it turns out that the spin flip practically never occurs in this process. For both cases, spinless and spin-1/2, the outgoing photon polarization vector lies always in the plane formed by the initial particle's momentum vector and the final photon's wave vector.

   hep-phphysics.opticsquant-ph1 citation
2. 02*

   High energy resummation of transverse momentum distributions:Higgs in gluon fusion

   Stefano Forte🇮🇹 · Claudio Muselli🇮🇹

   We derive a general resummation formula for transverse-momentum distributions of hard processes at the leading logarithmic level in the high-energy limit, to all orders in the strong coupling. Our result is based on a suitable generalization of high-energy factorization theorems, whereby all-order resummation is reduced to the determination of the Born-level process but with incoming off-shell gluons. We validate our formula by applying it to Higgs production in gluon fusion in the infinite top mass limit. We check our result up to next-to-leading order by comparison to the high energy limit of the exact expression and to next-to-next-to leading by comparison to NNLL order trasverse momentum (Sudakov) resummation, and we predict the high-energy behaviour at next${}^3$-to-leading order. We also show that the structure of the result in the small transverse momentum limit agrees to all orders with general constraints from Sudakov resummation.

   hep-phJHEP(2016)·40 citations
3. 03*

   Non-standard Neutrino Interactions at DUNE

   André de Gouvêa🇺🇸 · Kevin J. Kelly🇺🇸

   We explore the effects of non-standard neutrino interactions (NSI) and how they modify neutrino propagation in the Deep Underground Neutrino Experiment (DUNE). We find that NSI can significantly modify the data to be collected by the DUNE experiment as long as the new physics parameters are large enough. For example, If the DUNE data are consistent with the standard three-massive-neutrinos paradigm, order 0.1 (in units of the Fermi constant) NSI effects will be ruled out. On the other hand, if large NSI effects are present, DUNE will be able to not only rule out the standard paradigm but also measure the new physics parameters, sometimes with good precision. We find that, in some cases, DUNE is sensitive to new sources of CP-invariance violation. We also explored whether DUNE data can be used to distinguish different types of new physics beyond nonzero neutrino masses. In more detail, we asked whether NSI can be mimicked, as far as the DUNE setup is concerned, by the hypothesis that there is a new light neutrino state.

   hep-phhep-exNPB(2016)·160 citations
4. 04*

   Production of heavy Higgs bosons and decay into top quarks at the LHC

   W. Bernreuther🇩🇪 · P. Galler🇩🇪 · C. Mellein🇩🇪 · Z.-G. Si🇨🇳 · P. Uwer🇩🇪

   We investigate the production of heavy, neutral Higgs boson resonances and their decays to top-quark top-antiquark ($t\bar{t}$) pairs at the Large Hadron Collider (LHC) at next-to-leading order (NLO) in the strong coupling of quantum chromodynamics (QCD). The NLO corrections to heavy Higgs boson production and the Higgs-QCD interference are calculated in the large $m_t$ limit with an effective K-factor rescaling. The nonresonant $t\bar{t}$ background is taken into account at NLO QCD including weak-interaction corrections. In order to consistently determine the total decay widths of the heavy Higgs bosons, we consider for definiteness the type-II two-Higgs-doublet extension of the standard model and choose three parameter scenarios that entail two heavy neutral Higgs bosons with masses above the $t\bar{t}$ threshold and unsuppressed Yukawa couplings to top quarks. For these three scenarios we compute, for the LHC operating at 13 TeV, the $t\bar{t}$ cross section and the distributions of the $t\bar{t}$ invariant mass, of the transverse top-quark momentum and rapidity, and of the cosine of the Collins-Soper angle with and without the two heavy Higgs resonances. For selected $M_{t\bar{t}}$ bins we estimate the significances for detecting a heavy Higgs signal in the $t\bar{t}$ dileptonic and lepton plus jets decay channels.

   hep-phPRD(2016)·53 citations
5. 05*

   The Universal Transverse Momentum Dependent Soft Function at NNLO

   Miguel G. Echevarria🇳🇱 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

   All (un)polarized transverse momentum dependent functions (TMDs), both distribution and fragmentation functions, are defined with the same universal soft function, which cancels spurious rapidity divergences within an individual TMD and renders them well-defined hadronic quantities. Moreover, it is independent of the kinematics, whether it is Drell-Yan, deep inelastic scattering or $e^{+}{e}^{-}\to 2$ hadrons. In this paper we provide this soft function at next-to-next-to-leading order (NNLO), necessary for the calculation of all TMDs at the same order, and to perform the resummation of large logarithms at next-to-next-to-next-to-leading-logarithmic accuracy. From the results we obtain the $D$ function at NNLO, which governs the evolution of all TMDs. This work represents the first independent and direct calculation of this quantity. Given the all order relation through a Casimir scaling between the soft function relevant for gluon TMDs and the one for quark TMDs, we also obtain the first at NNLO. The used regularization method to deal with the rapidity divergences is discussed as well.

   hep-phhep-thPRD(2016)·160 citations
6. 06*

   Axino dark matter and baryon number asymmetry production by the Q-ball decay in gauge mediation

   Shinta Kasuya🇯🇵 · Etsuko Kawakami🇯🇵 · Masahiro Kawasaki🇯🇵

   We investigate the Q-ball decay into the axino dark matter in the gauge-mediated supersymmetry breaking. In our scenario, the Q ball decays mainly into nucleons and partially into axinos to account respectively for the baryon asymmetry and the dark matter of the universe. The Q ball decays well before the big bang nucleosynthesis so that it is not affected by the decay. We show the region of the parameters which realizes this scenario.

   hep-phJCAP(2016)·3 citations
7. 07*

   Pion photo- and electroproduction and the chiral MAID interface

   M. Hilt🇩🇪 · B. C. Lehnhart🇩🇪 · S. Scherer🇩🇪 · L. Tiator🇩🇪

   We discuss the extended on-mass-shell scheme for manifestly Lorentz-invariant baryon chiral perturbation theory. We present a calculation of pion photo- and electroproduction up to and including order $q^4$. The low-energy constants have been fixed by fitting experimental data in all available reaction channels. Our results can be accessed via a web interface, the so-called chiral MAID (http://www.kph.uni-mainz.de/MAID/chiralmaid/). We explain how our program works and how it can be used for further analysis.

   hep-phnucl-exnucl-thPoS(2016)·0 citations
8. 08*

   Hadronic contribution from light by light processes in (g-2) of muon in nonlocal quark model

   A.S. Zhevlakov (TSU)🇷🇺 · A.E. Dorokhov (JINR)🇷🇺 · A.E. Radzhabov (IDSTU SB RAS)🇷🇺

   The hadronic corrections to the muon anomalous magnetic moment, due to the full gauge-invariant set of diagrams with dynamical quark loop and intermediate pseudoscalar and scalar states light-by-light scattering insertions, are calculated in the framework of the nonlocal chiral quark model. These diagrams correspond to all hadronic light-by-light scattering contributions to $a_{\mu }$ in the leading order of the $1/N_c$ expansion in quark model. The result for the quark loop contribution is $a_{\mu }^{\mathrm{HLbL},\mathrm{Loop}}=\left(11.0\pm 0.9\right)\cdot 10^{-10}$, and the total result is $a_{\mu }^{\mathrm{HLbL},\mathrm{N}\chi \mathrm{QM}}=\left(16.8\pm 1.2\right)\cdot 10^{-10}$.

   hep-phJ.Univ.Sci.Tech.China(2016)·1 citation
9. 09*

   Triplet production by a polarized photon beam on a polarized electron target

   G.I. Gakh🇺🇦 · M.I. Konchatnij🇺🇦 · N.P. Merenkov🇺🇦

   Polarized and unpolarized observables in the process of the triplet photoproduction on a free electron, $\gamma +e\to e+e+e$, have been calculated in the laboratory system. These observables are calculated in the approximation when the Borsellino and $\gamma -e$ diagrams are taken into account. Using the method of the invariant integration over the produced electron-positron pair variables, the different distributions were obtained in the analytical form. We obtain the double distribution over the $q^2$ (the square of the four-momentum transfer to the recoil electron) and $Q^2$ (the created $e^{+}{e}^{-}$-pair invariant mass squared) variables, and single distributions over $q^2$ or $Q^2$ variables. We consider the following cases: unpolarized particles, the photon beam is linearly polarized and circularly polarized photon beam interacts with a polarized electron target. The influence of the $\gamma -e$ terms on the calculated observables has been investigated. The possibility to use this process for the measurement of the circular polarization of the high-energy photon beam is also considered. The numerical estimations of various polarization observables have been done.

   hep-ph2 citations
10. 10*

    Resonant production of leptogluons at the FCC based lepton-hadron colliders

    Y. C. Acar🇹🇷 · U. Kaya🇹🇷 · B. B. Oner🇹🇷 · S. Sultansoy🇹🇷

    Resonant production of leptogluons at the FCC based ep and \mup colliders have been analyzed. It is shown that e-FCC and \mu-FCC will cover much wider region of e_{8} and \mu_{8} masses than the LHC. While leptogluons with appropriate masses (if exist) will be discovered earlier by the FCC pp collider, lepton-proton colliders will give opportunity to handle very important additional information. For example, compositeness scale can be probed up to multi-hundred TeV region.

    hep-phhep-ex2 citations
11. 11*

    Photonic dark matter portal revisited

    S. A. Alavi🇮🇷 · F S Kazemian🇮🇷

    In our previous paper [1], we studied a model of dark matter (DM) in which the hidden sector interacts with standard model particles via a hidden photonic portal (HP). We investigated the effects of this new interaction on the hydrogen atom and obtained an upper bound for the coupling of the model. In this work, we study the effects of HP on two interesting exotic atoms namely muonium and positronium. We obtain a tighter upper limit on the coupling. We also calculate the change (shift) in the Aharonov-Bohm phase due to HP and find that the phase shift is negligibly small (for DM particles mass in the GeV range). Recently a 3.5 keV X ray line signal observed in the spectrum of 73 galaxy clusters, reported by the XXM-Newton X ray observatory. Since in HP model the DM particles can decay directly into photons, so we finally calculate the value of the coupling constant f using the condition Delta E=3.5 keV.

    hep-phJ.Phys.Conf.Ser.(2016)·1 citation
12. 12*

    SU(2N_F) hidden symmetry of QCD

    L. Ya. Glozman🇦🇹

    Recently a global SU(4) \supset SU(2)_L \times SU(2)_R \times U(1)_A symmetry of the confining Coulombic part of the QCD Hamiltonian has been discovered with N_F=2. This global symmetry includes both independent rotations of the left- and right-handed quarks in the isospin space as well as the chiralspin rotations that mix the left- and right-handed components of the quark fields. It has been suggested by lattice simulations, however, that a symmetry of mesons in the light quark sector upon the quasi-zero mode truncation from the quark propagators is actually higher than SU(4), because the states from a singlet and a 15-plet irreducible representations of SU(4) are also degenerate. Here we demonstrate that classically QCD, ignoring irrelevant exact zero mode contributions, has a SU(2N_F) symmetry. If effects of dynamical chiral symmetry breaking and of anomaly are encoded in the same near-zero modes, then truncation of these modes should restore a classical SU(2N_F) symmetry. Then we show in a Lorentz- and gauge-invariant manner emergence of a bilocal SU(4) \times SU(4) symmetry in mesons that contains a global SU(4) as a subgroup upon truncation of the quasi-zero modes. We also demonstrate that the confining Coulombic part of the QCD Hamiltonian has this bilocal symmetry. It explains naturally a degeneracy of different irreducible representations of SU(4) observed in lattice simulations.

    hep-phhep-lathep-thnucl-th14 citations
13. 13*

    Decay Constants of Heavy-Light Mesons from QCD

    Stephan Narison (LUPM, CNRS/IN2P3 and University of Montpellier-FRA)🇫🇷

    We summarize recently improved results for the pseudoscalar [1,2] and vector [3] meson decay constants and their ratios from QCD spectral sum rules where N2LO + estimate of the N3LO PT and power corrections up to d< 6 dimensions have been included in the SVZ expansion. The "optimal results" based on stability criteria with respect to the variations of the Laplace/Moments sum rule variables, QCD continuum threshold and subtraction constant \mu are compared with recent sum rules and lattice calculations. To understand the "apparent tension" between some recent results for f_B*/f_B, we present in Section 8 "a novel extraction" of this ratio from heavy quark effective theory (HQET) sum rules by including the normalization factor (M_b/M_B)^2 relating the pseudoscalar to the universal HQET correlators for finite b-quark and B-meson masses. We obtain f_B*/f_B=1.025(16) in good agreement with the one 1.016(16) from (pseudo)scalar sum rules in full QCD [3]. We complete the paper by including new improved estimates of the scalar, axial-vector and B^*_c meson decays constants (Sections 11-13). For further phenomenological uses, we attempt to extract a Global Average of different sum rules and lattice determinations of the decay constants which are summarized in Tables 2-6. We do not found any deviation of these SM results from the present data.

    hep-phhep-exhep-latNucl.Part.Phys.Proc.(2016)·49 citations
14. 14*

    $\Psi (2S)$ Decay to $J/\Psi (1S)$ + 2$\pi$ or $J/\Psi (1S)$ +$\sigma$ + 2$\pi$

    Leonard S. Kisslinger · Zhou Li-juan · Ma Wei-xing

    The BES Collaboration has measured $\Psi (2S)$ decay to $J/\Psi {\pi }^{+}{\pi }^{-}$. Using the mixed hybrid theory for the $\Psi (2S)$ we estimate the decay to $J/\Psi (1S)$ + $\sigma$. Using the known $\sigma \to 2\pi$ coupling constant, we estimate the $\Psi (2S)$ to $J/\Psi (1S)$ + $2\pi$ decay rate and angular distribution. This is an extension of our previous research on $\Psi (2S)$ Decay to $J/\Psi (1S)$ +$\sigma$ + 2${\pi }^o$, without the production of 2${\pi }^o$, and with an estimate of the $\sigma \to {\pi }^{+}+{\pi }^{-}$ transition.

    hep-phInt.J.Theor.Phys.(2017)·1 citation
15. 15*

    Modulated Natural Inflation

    Rolf Kappl🇩🇪 · Hans Peter Nilles🇩🇪 · Martin Wolfgang Winkler🇩🇪

    We discuss some model-independent implications of embedding (aligned) axionic inflation in string theory. As a consequence of string theoretic duality symmetries the pure cosine potentials of natural inflation are replaced by modular functions. This leads to "wiggles" in the inflationary potential that modify the predictions with respect to CMB-observations. In particular, the scalar power spectrum deviates from the standard power law form. As a by-product one can show that trans-Planckian excursions of the aligned effective axion are compatible with the weak gravity conjecture.

    ↳ hep-thastro-ph.COhep-phPLB(2016)·84 citations
16. 16*

    Mapping dark matter in the Milky Way, a synopsis

    Miguel Pato🇸🇪 · Fabio Iocco🇧🇷

    Mapping the dark matter distribution across our Galaxy represents a central challenge for the near future as a new generation of space-borne and ground-based astronomical surveys swiftly comes online. Here we present a synopsis of the present status of the field, reviewing briefly the baryonic content and the kinematics of the Milky Way and outlining the methods used to infer the dark matter component. The discussion then proceeds with some of the latest developments based on our own work. In particular, we present a new compilation of kinematic measurements tracing the rotation curve of the Galaxy and an exhaustive array of observation-based baryonic models setting the contribution of stellar bulge, stellar disc and gas to the total gravitational potential. The discrepancy between these two components is then quantified to derive the latest constraints on the dark matter distribution and on modified Newtonian dynamics. We shall end with an overview of future directions to improve our mapping of the dark matter distribution in the Milky Way.

    ↳ astro-ph.GAhep-exhep-phPoS(2016)·4 citations
17. 17*

    On the axial $U(1)$ symmetry at finite temperature

    JLQCD Collaboration: Guido Cossu🇯🇵 · Hidenori Fukaya🇯🇵 · Shoji Hashimoto🇯🇵 · Jun-ichi Noaki🇯🇵 · Akio Tomiya🇨🇳

    We study the $U(1{)}_A$ anomaly in two-flavor lattice QCD at finite temperature with the Möbius domain-wall Dirac operator. We generate gauge configurations in the temperature range $(0.9,1.2)T_c$ on different physical volumes, $L=$ 2--4 fm, and lattice spacings. We measure the difference of the susceptibilities of the flavor non-singlet scalar (${\chi }_{\delta }$) and pseudoscalar (${\chi }_{\pi }$) mesons. They are related by an axial $U(1)$ transformation and the difference vanishes if the axial $U(1)$ symmetry is respected. We identify the source of axial $U(1)$ symmetry breaking at finite temperature in the lowest eigenmodes, for the observable ${\chi }_{\pi }-{\chi }_{\delta }$. We then reweight the Möbius domain-wall fermion partition function to that of the overlap-Dirac operator to fully recover chiral symmetry. Our data show a significant discrepancy in the results coming from the Möbius domain-wall valence quarks, the overlap valence quarks on our DWF configurations and the reweighted ones that have full chiral symmetry. After recovering full chiral symmetry we conclude that the difference ${\chi }_{\pi }-{\chi }_{\delta }$ shows a suppression in the chiral limit that is compatible with an effective restoration of $U(1{)}_A$ at $T\gtrsim T_c$ in the scalar meson channels.

    ↳ hep-lathep-phPoS(2016)·12 citations
18. 18*

    COSMOS-$e^{\prime }$-GTachyon from String Theory

    Sayantan Choudhury🇮🇳 · Sudhakar Panda🇮🇳

    In this article, our prime objective is to study the inflationary paradigm from generalized tachyon (GTachyon) living on the world volume of a non-BPS string theory. The tachyon action is considered here is getting modified compared to the original action. One can quantify the amount of the modification via a power $q$ instead of $1/2$ in the effective action. Using this set up we study inflation from various types of tachyonic potentials, using which we constrain the index $q$ within, $1/2<q<2$, Regge slope ${\alpha }^{{}^{\prime }}$, string coupling constant $g_s$ and mass scale of tachyon $M_s$, from the recent Planck 2015 and Planck+BICEP2/Keck Array joint data. We explicitly study the inflationary consequences from single field, assisted field and multi-field tachyon set up. Specifically for single field and assisted field case we derive the results in the quasi-de-Sitter background in which we will utilize the details of cosmological perturbations and quantum fluctuations. Also we derive the expressions for all inflationary observables using any arbitrary vacuum and Bunch-Davies vacuum. For single field and assisted field case we derive-the inflationary flow equations, new sets of consistency relations. Also we derive the field excursion formula for tachyon, which shows that assisted inflation is in more safer side compared to the single field case to validate effective field theory framework. Further we study the features of CMB Angular power spectrum from TT, TE and EE correlations from scalar fluctuations within the allowed range of $q$ for each potentials from single field set-up. We also put constraints from the temperature anisotropy and polarization spectra, which shows that our analysis is consistent with the Planck 2015 data. Finally, using $\delta N$ formalism we derive the expressions for inflationary observables in the context of multi-field tachyons.

    ↳ hep-thastro-ph.COgr-qchep-phEPJC(2016)·40 citations
19. 19*

    Lattice calculation of the HVP contribution to the anomalous magnetic moment of muon

    Bipasha Chakraborty🇬🇧 · Christine Davies🇬🇧 · Pedro Gonçalves de Oliveira🇬🇧 · Jonna Koponen🇬🇧 · G. Peter Lepage🇺🇸

    We report our (HPQCD) progress on the calculation of the Hadronic Vacuum Polarisation contribution to the anomalous magnetic moment of muon. In this article we discuss the calculations for the light (up/down) quark connected contribution using our method described in Phys.Rev. D89(2014) 11, 114501 and give an estimate for the disconnected contribution. Our calculation has been carried out on MILC Collaboration's $n_f=2+1+1$ HISQ ensembles at multiple values of the lattice spacing, multiple volumes and multiple light sea quark masses (including physical pion mass configurations).

    ↳ hep-lathep-exhep-phnucl-thPoS(2015)·5 citations
20. 20*

    Excluded volume effects in the hybrid star EoS

    D. E. Alvarez-Castillo🇷🇺 · M. A. R. Kaltenborn🇵🇱 · D. Blaschke🇷🇺

    In this contribution, we outline a new 2-phase description of the quark-nuclear matter hybrid equation of state that takes into account effects of phase space occupation (excluded volume) in both, the hadronic and the quark matter phases. For the nuclear matter phase, the reduction of the available volume at increasing density leads to a stiffening, while for the quark matter phase a reduction of the effective string tension in the confining density functional is obtained. The deconfinement phase transition in the resulting hybrid equation of state is sensitive to both excluded volume effects. As an application, we consider matter under compact star constraints of electric neutrality and $\beta$-equilibrium. We obtain mass-radius relations for hybrid stars that fulfill the $2M_{\odot }$ constraint and exhibit the high-mass twin phenomenon. Both features depend sensitively on the excluded volume.

    ↳ nucl-thastro-ph.HEhep-phJ.Phys.Conf.Ser.(2016)·4 citations
21. 21*

    Towards a new quark-nuclear matter EoS for applications in astrophysics and heavy-ion collisions

    N.-U. Bastian🇵🇱 · D. Blaschke🇷🇺

    The aim of our work is to develop a unified equation of state (EoS) for nuclear and quark matter for a wide range in temperature, density and isospin so that it becomes applicable for heavy-ion collisions as well as for the astrophysics of neutron stars, their mergers and supernova explosions. As a first step, we use improved EoS for the hadronic and quark matter phases and join them via Maxwell construction. We discuss the limitations of a 2-phase description and outline steps beyond it, towards the formulation of a unified quark-nuclear matter EoS on a more fundamental level by a cluster virial expansion.

    ↳ nucl-thhep-phJ.Phys.Conf.Ser.(2016)·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.