Tue·Nov 24, 2015Tuesday·November 24, 2015

1. 01*

   Helicity Evolution at Small-x

   Yuri V. Kovchegov🇺🇸 · Daniel Pitonyak🇺🇸 · Matthew D. Sievert🇺🇸

   We construct small-x evolution equations which can be used to calculate quark and anti-quark helicity TMDs and PDFs, along with the $g_1$ structure function. These evolution equations resum powers of ${\alpha }_s{\ln }^2(1/x)$ in the polarization-dependent evolution along with the powers of ${\alpha }_s\ln (1/x)$ in the unpolarized evolution which includes saturation effects. The equations are written in an operator form in terms of polarization-dependent Wilson line-like operators. While the equations do not close in general, they become closed and self-contained systems of non-linear equations in the large-$N_c$ and large-$N_c\&N_f$ limits. As a cross-check, in the ladder approximation, our equations map onto the same ladder limit of the infrared evolution equations for $g_1$ structure function derived previously by Bartels, Ermolaev and Ryskin.

   hep-phhep-exJHEP(2016)·153 citations
2. 02*

   A Model of Neutrinos

   Alan Chodos🇺🇸

   We propose a model for neutrinos based on symmetry under light-cone reflection (LCR), which was introduced in a previous paper. LCR is realized using a minimal substitution, which allows the equations of motion to be solved after a suitable coordinate transformation. Some consequences of this proposal are discussed.

   hep-ph4 citations
3. 03*

   Spin asymmetries for vector boson production in polarized p+p collisions

   Jin Huang🇺🇸 · Zhong-Bo Kang🇺🇸 · Ivan Vitev🇺🇸 · Hongxi Xing🇺🇸

   We study the cross section for vector boson ($W^{\pm }/Z^0/{\gamma }^{\ast }$) production in polarized nucleon-nucleon collisions for low transverse momentum of the observed vector boson. For the case where one measures the transverse momentum and azimuthal angle of the vector bosons, we present the cross sections and the associated spin asymmetries in terms of transverse momentum dependent parton distribution functions (TMDs) at tree level within the TMD factorization formalism. To assess the feasibility of experimental measurements, we estimate the spin asymmetries for $W^{\pm }/Z^0$ boson production in polarized proton-proton collisions at the Relativistic Heavy Ion Collider (RHIC) by using current knowledge of the relevant TMDs. We find that some of these asymmetries can be sizable if the suppression effect from TMD evolution is not too strong. The $W$ program at RHIC can, thus, test and constrain spin theory by providing unique information on the universality properties of TMDs, TMD evolution, and the nucleon structure. For example, the single transverse spin asymmetries could be used to probe the well-known Sivers function $f_{1T}^{\perp q}$, as well as the transversal helicity distribution $g_{1T}^q$ via the parity-violating nature of $W$ production.

   hep-phhep-exnucl-exPRD(2016)·17 citations
4. 04*

   Nonthermal production of dark radiation and dark matter

   Matthew Reece🇺🇸 · Thomas Roxlo🇺🇸

   Dark matter may be coupled to dark radiation: light degrees of freedom that mediate forces between dark sector particles. Cosmological constraints favor dark radiation that is colder than Standard Model radiation. In models with fixed couplings between dark matter and the Standard Model, these constraints can be difficult to satisfy if thermal equilibrium is assumed in the early universe. We construct a model of asymmetric reheating of the visible and dark sectors from late decays of a long-lived particle (for instance, a modulus). We show, as a proof-of-principle, that such a model can populate a sufficiently cold dark sector while also generating baryon and dark matter asymmetries through the out of equilibrium decay. We frame much of our discussion in terms of the scenario of dissipative dark matter, as in the Double-Disk Dark Matter scenario. However, our results may also be of interest for other scenarios like the Twin Higgs model that are in danger of overproducing dark radiation due to nonnegligible dark-visible couplings.

   hep-phJHEP(2016)·45 citations
5. 05*

   Issues and Opportunities in Exotic Hadrons

   R.A. Briceno🇺🇸 · T.D. Cohen🇺🇸 · S. Coito🇨🇳 · J.J. Dudek🇺🇸 · E. Eichten🇺🇸 · C.S. Fischer🇩🇪 · M. Fritsch🇩🇪 · W. Gradl🇩🇪 · A. Jackura🇺🇸 · M. Kornicer🇺🇸 · G. Krein🇧🇷 · R.F. Lebed🇺🇸 and 13 other authors

   The last few years have been witness to a proliferation of new results concerning heavy exotic hadrons. Experimentally, many new signals have been discovered that could be pointing towards the existence of tetraquarks, pentaquarks, and other exotic configurations of quarks and gluons. Theoretically, advances in lattice field theory techniques place us at the cusp of understanding complex coupled-channel phenomena, modelling grows more sophisticated, and effective field theories are being applied to an ever greater range of situations. It is thus an opportune time to evaluate the status of the field. In the following, a series of high priority experimental and theoretical issues concerning heavy exotic hadrons is presented.

   hep-phhep-latCPC(2016)·97 citations
6. 06*

   Double parton scattering: Impact of nonperturbative parton correlations

   Sergey Ostapchenko🇩🇪 · Marcus Bleicher🇩🇪

   We apply the phenomenological Reggeon Field Theory framework to investigate the relative importance of perturbative and nonperturbative multiparton correlations for the treatment of double parton scattering (DPS) in proton-proton collisions. We obtain a significant correction to the so-called effective cross section for DPS due to nonperturbative parton splitting. When combined with the corresponding perturbative contribution, this results in a rather weak energy and transverse momentum dependence of the effective cross section, in agreement with experimental observations at the Tevatron and the Large Hadron Collider. In addition, we observed that color fluctuations have a sizable impact on the calculated rate of double parton scattering and on the relative importance of the perturbative parton splitting mechanism.

   hep-phPRD(2016)·13 citations
7. 07*

   Enhanced creation of high energy particles in colliding laser beams

   Michael Kuchiev🇦🇺 · Julian Ingham🇦🇺

   The creation of particles by two colliding strong laser beams is considered. It is found that the electron-positron pairs created in the laser field via the Schwinger mechanism may recollide after one or several oscillations in the field. Their collision can take place at high energy, which the pair gains from the field. As a result, high energy gamma quanta can be created by inelastic scattering or annihilation of the pair. Moreover, heavy particles such as muon pairs may also be created via the annihilation $e^{+}+e^{-}\to {\mu }^{+}+{\mu }^{-}$. The probability of $e^{-}{e}^{+}$ collision is greatly enhanced due to a strong alignment of the electron and positron momenta with the electric field. The found muon creation rate exponentially exceeds the rate predicted by the direct Schwinger mechanism for muons, while the photon creation rate exponentially exceeds photon emission due to the fermion oscillation.

   hep-ph3 citations
8. 08*

   Quark CP-Phase and Froggatt-Nielsen Mechanism

   Chuichiro Hattori (1)🇯🇵 · Masahisa Matsuda (2)🇯🇵 · Mamoru Matsunaga (3)🇯🇵 · Takeo Matsuoka (3) ((1) Aichi Institute of Technology, (2) Nara University of Education, (3) Mie University)🇯🇵

   On the basis of the Froggatt-Nielsen mechanism, we study quark flavor mixings in the $SU(6)\times SU(2{)}_R$ model. The characteristic structure of the CKM matrix is attributed to the hierarchical effective Yukawa couplings due to the Froggatt-Nielsen mechanism and also to the state-mixings beyond the MSSM. We elucidate the detailed form of the CKM matrix elements and find interesting relations between the \textit{CP} violating phase and three mixing angles. Taking the existing data of three mixing angles, we estimate the quark \textit{CP}-phase at $\delta =(75\pm 3{)}^{\circ }$. This result is in accord with observations.

   hep-phPLB(2016)·0 citations
9. 09*

   Searching for minimum in dependence of squared speed-of-sound on collision energy

   Fu-Hu Liu🇨🇳 · Li-Na Gao🇨🇳 · Roy A. Lacey🇺🇸

   Experimental results of the rapidity distributions of negatively charged pions produced in proton-proton ($p$-$p$) and beryllium-beryllium (Be-Be) collisions at different beam momentums, measured by the NA61/SHINE Collaboration at the super proton synchrotron (SPS), are described by a revised (three-source) Landau hydrodynamic model. The squared speed-of-sound parameter $c_s^2$ is then extracted from the width of rapidity distribution. There is a local minimum (knee point) which indicates a softest point in the equation of state (EoS) appearing at about 40$A$ GeV/$c$ (or 8.8 GeV) in $c_s^2$ excitation function [the dependence of $c_s^2$ on incident beam momentum (or center-of-mass energy)]. This knee point should be related to the searching for the onset of quark deconfinement and the critical point of quark-gluon plasma (QGP) phase transition.

   hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2016)·5 citations
10. 10*

    Higgs bosons in supersymmetric model with CP-violating potential

    Noriyuki Oshimo🇯🇵

    In the supersymmetric standard model which is not minimal, the Higgs potential does not conserve CP symmetry generally. Assuming that there exists an SU(2)-triplet Higgs field, we discuss resultant CP-violating effects on the Higgs bosons. The experimentally observed Higgs boson, which should be CP-even in the standard model, could decay into two photons of CP-odd polarization state non-negligibly. For the second lightest Higgs boson, in sizable region of parameter space, the dominant decay modes are different from those expected by the standard model. The two-photon decay could yield both even and odd CP final states at a ratio of oder of unity.

    hep-phPRD(2016)·1 citation
11. 11*

    Old Wine in a New Bottle: Technidilaton as the 125 GeV Higgs -- Dedicated to the late Professor Yoichiro Nambu

    Koichi Yamawaki🇯🇵

    We show that the Standard Model (SM) Higgs Lagrangian is identical to the nonlinear realization of both the scale and chiral symmetries ("scale-invariant nonlinear sigma model"), and is further gauge equivalent to the "scale-invariant Hidden Local Symmetry (HLS) model" having possible new vector bosons as the HLS gauge bosons with scale-invariant mass: SM Higgs is nothing but a (pseudo) dilaton. The effective theory of the walking technicolor has precisely the same type of the scale-invariant nonlinear sigma model, thus further having the scale-invariant HLS gauge bosons (technirho's, etc.). The technidilaton mass M_\phi comes from the trace anomaly, which yields M_\phi^2 F_\phi^2 \simeq (2.5)^2 [(8/N_F)(4/N_C)] v^4 via PCDC, in the underlying walking SU(N_C) gauge theory with N_F massless flavors, where F_\phi is the decay constant and v=246 GeV. This implies F_\phi \simeq 5 v for M_\phi \simeq 125 GeV \simeq v/2 in the one-family walking technicolor model (N_F=8, N_C=4), in good agreement with the current LHC Higgs data. In the anti-Veneziano limit, N_C \rightarrow \infty, with N_C \alpha= fixed and N_F/N_C= fixed (\gg 1), we have a result: M_\phi^2/v^2\sim M_\phi^2/F_\phi^2 \sim 1/(N_F N_C) \rightarrow 0. Then the technidilaton is a naturally light composite Higgs out of the strongly coupled conformal dynamics, with its couplings even weaker than the SM Higgs.

    hep-phhep-latInt.J.Mod.Phys.A(2017)·14 citations
12. 12*

    On the flavour dependence of the $\mathcal{O}({\alpha }_s^4)$ correction to the relation between running and pole heavy quark masses

    A.L. Kataev🇷🇺 · V.S. Molokoedov🇷🇺

    Recently the four-loop perturbative QCD contributions to the relations between pole and running masses of charm, bottom and top quarks were evaluated in the $\overline{\mathrm{MS}}$-scheme with identical numerical error bars. In this work the flavour dependence of the $\mathcal{O}({\alpha }_s^4)$ correction to these asymptotic series is obtained in the semi-analytical form with the help of the least squares method. The numerical structure of the corresponding asymptotic perturbative relations between pole and running $c$, $b$ and $t$-quark masses is considered and the theoretical errors of the $\mathcal{O}({\alpha }_s^4)$-contributions are discussed. The explicit dependence for these relations on the renormalization scale ${\mu }^2$ and the flavour number $n_l$ is presented.

    hep-phhep-exhep-thEur.Phys.J.Plus(2016)·37 citations
13. 13*

    Phenomenology of transverse spin: past, present and future

    Mariaelena Boglione🇮🇹 · Alexei Prokudin🇺🇸

    We summarize the most significant aspects in the study of transverse spin phenomena over the last few decades, focusing on Semi-Inclusive Deep Inelastic Scattering processes and hadronic production in $e^{+}{e}^{-}$ annihilations. The phenomenology of transverse momentum dependent distribution and fragmentation functions will be reviewed in an in-depth analysis of the most recent developments and of the future perspectives.

    hep-phEPJA(2016)·42 citations
14. 14*

    Vector Meson Masses from Hidden Local Symmetry in Constant Magnetic Field

    Mamiya Kawaguchi🇯🇵 · Shinya Matsuzaki🇯🇵

    We discuss the magnetic responses of vector meson masses based on the hidden local symmetry (HLS) model in constant magnetic field, described by the lightest two-flavor system including the pion, rho and omega mesons in the spectrum. The effective masses influenced under the magnetic field are evaluated in a way of the derivative/chiral expansion established in the HLS model. At the leading order O(p^2) the g-factor of the charged rho meson is fixed to be 2, implying that the rho meson at this order is treated just like a point-like spin-1 particle. Beyond the leading order, one finds anomalous magnetic interactions of the charged rho meson, involving the anomalous magnetic moment, which give corrections to the effective mass. It is then suggested that up to O(p^4) the charged rho meson tends to become massless. Of interest is that nontrivial magnetic-dependence of neutral mesons emerges to give rise to the significant mixing among neutral mesons. Consequently, it leads to the dramatic enhancement of the omega meson mass, which is testable in future lattice simulations. Corrections from terms beyond O(p^4) are also addressed.

    hep-phhep-latnucl-thPRD(2016)·39 citations
15. 15*

    $a_1(1260),a_1(1420)$ and the production in heavy meson decays

    Wei Wang🇨🇳 · Zhen-Xing Zhao🇨🇳

    The $a_1(1420)$ with $I^G(J^{PC})=1^{-}(1^{++})$ observed in the ${\pi }^{+}{f}_0(980)$ final state in the ${\pi }^{-}p\to {\pi }^{+}{\pi }^{-}{\pi }^{-}p$ process by the COMPASS collaboration seems unlikely to be an ordinary $\bar{q}q$ mesonic state. Available theoretical explanations include tetraquark or rescattering effects due to $a_1(1260)$ decays. If the $a_1(1420)$ were induced by the rescattering, its production rates are completely determined by those of the $a_1(1260)$. In this work, we propose to explore the ratios of branching fractions of heavy meson weak decays into the $a_1(1420)$ and $a_1(1260)$, and testing the universality of these ratios would be a straightforward way to validate/invalidate the rescattering explanation. The decay modes include in the charm sector the $D^0\to a_1^{-}{\ell }^{+}\nu$ and $D^0\to {\pi }^{\pm }{a}_1^{\mp }$, and in the bottom sector ${\overline{B}}^0\to a_1^{+}{\ell }^{-}\bar{\nu }$, $B\to D{a}_1,{\pi }^{\pm }{a}_1^{\mp }$, $B_c\to J/\psi a_1$ and ${\Lambda }_b\to {\Lambda }_c{a}_1$. We calculate the branching ratios for various decay modes into the $a_1(1260)$. The numerical results indicate that there is a promising prospect to study these decays on experiments including BES-III, LHCb, Babar, Belle and CLEO-c, the forthcoming Super-KEKB factory and the under-design Circular Electron-Positron Collider. Experimental analyses in future will lead to a deeper understanding of the nature of the $a_1(1420)$.

    hep-phhep-exEPJC(2016)·18 citations
16. 16*

    Two-gluon and trigluon glueballs from dynamical holography QCD

    Yidian Chen🇨🇳 · Mei Huang🇨🇳

    We study the scalar, vector and tensor two-gluon and trigluon glueball spectra in the framework of 5-dimension dynamical holographic QCD model, where the metric structure is deformed self-consistently by the dilaton field. For comparison, the glueball spectra are also calculated in the hard-wall and soft-wall holographic QCD models. In order to distinguish glueballs with even and odd parities, we introduce the positive and negative coupling between the dilaton field and glueballs, and for higher spin glueballs, we introduce a deformed 5-dimension mass. With this set-up, there is only one free parameter from the quadratic dilaton profile in the dynamical holographic QCD model, which is fixed by the scalar glueball spectra. It is found that the two-gluon glueball spectra produced in the dynamical holographic QCD model are in good agreement with lattice data. Among six trigluon glueballs, the produced masses for $1^{\pm -}$ and $2^{--}$ are in good agreement with lattice data, and the produced masses for $0^{--}$, $0^{+-}$ and $2^{+-}$ are around 1.5 {\rm GeV} lighter than lattice results. This result might indicate that the three trigluon glueballs of $0^{--}$, $0^{+-}$ and $2^{+-}$ are dominated by three-gluon condensate contribution.

    hep-phCPC(2016)·26 citations
17. 17*

    Polarized forward-backward asymmetries of lepton pair in $B\to K_1{\ell }^{+}{\ell }^{-}$ decay in the presence of New physics

    Faisal Munir🇨🇳 · Saadi Ishaq🇨🇳 · Ishtiaq Ahmed🇧🇷

    Double polarized forward-backward asymmetries in $B\to K_1(1270,1400){\ell }^{+}{\ell }^{-}$ with $\ell =\mu ,\tau$ decays are studied, using most general non-standard local four-fermi interactions, where the mass eigenstates $K_1(1270)$ and $K_1(1400)$ are the mixture of ${}^1{P}_1$ and ${}^3{P}_1$ states with the mixing angle ${\theta }_K$. We have calculated the expressions of nine doubly polarized forward-backward asymmetries and it is presented that the polarized lepton pair forward-backward asymmetries are greatly influenced by the new physics. Therefore, these asymmetries are interesting tool to explore the status of new physics in near future, specially at LHC.

    hep-phPTEP(2016)·10 citations
18. 18*

    The Matrix Element Method at next-to-leading order accuracy

    Till Martini🇩🇪 · Peter Uwer🇩🇪

    The Matrix Element Method (MEM) has proven beneficial to make maximal use of the information available in experimental data. However, so far it has mostly been used in Born approximation only. In this paper we discuss an extension to NLO accuracy. As a prerequisite we present an efficient method to calculate event weights for jet events at NLO accuracy. As illustration and proof of concept we apply the method to the extraction of the top-quark mass in e+e- annihilation. We observe significant differences when moving from LO to NLO which may be relevant for the interpretation of top-quark mass measurements at hadron colliders relying on the MEM.

    hep-phhep-exActa Phys.Polon.B(2015)·4 citations
19. 19*

    Alignment, reverse alignment, and wrong sign Yukawa couplings in two Higgs doublet models

    Ambalika Biswas🇮🇳 · Amitabha Lahiri🇮🇳

    We consider two Higgs doublet models with a softly broken U(1) symmetry, for various limiting values of the scalar mixing angles $\alpha$ and $\beta$. These correspond to the Standard Model Higgs particle being the lighter CP-even scalar (alignment) or the heavier CP-even scalar (reverse alignment), and also the limit in which some of the Yukawa couplings of this particle are of the opposite sign from the vector boson couplings (wrong sign). In these limits we impose a criterion for naturalness by demanding that quadratic divergences cancel at one loop. We plot the allowed masses of the remaining physical scalars based on naturalness, stability, perturbative unitarity and constraints coming from the $\rho$ parameter. We also calculate the $h\to \gamma \gamma$ decay rate in the wrong sign limit.

    hep-phPRD(2016)·22 citations
20. 20*

    Theoretical Results on Neutrinos

    Shun Zhou🇨🇳

    In this talk, I first summarize our current knowledge about the fundamental properties of neutrinos and emphasize the remaining unsolved problems in neutrino physics. Then, recent theoretical results on neutrino mass models are introduced. Different approaches to understanding tiny neutrino masses, lepton flavor mixing and CP violation are presented. Finally, I report briefly some new progress in the studies of astrophysical neutrinos, including keV sterile neutrinos, supernova neutrinos and ultrahigh-energy cosmic neutrinos.

    hep-phPoS(2016)·4 citations
21. 21*

    The Lee-Wick Extension of the Two-Higgs Doublet Model

    Aria R. Johansen🇺🇸 · Marc Sher🇺🇸 · Keith Thrasher🇺🇸

    The Lee-Wick Standard Model is a highly constrained model which solves the gauge hierarchy problem at the expense of including states with negative norm. It appears to be macroscopically causal and consistent. This model is extended by considering the two-Higgs doublet extension of the Lee-Wick model. Rewriting the Lagrangian using auxiliary fields introduces two additional doublets of Lee-Wick partners. The model is highly constrained, with only one or two additional parameters beyond that of the usual two-Higgs doublet model, and yet there are four doublets. Mass relations are established by diagonalizing the mass matrices and further constraints are established by studying results from B --> tau nu, neutral B-meson mixing, and B --> X_s gamma. The prospects of detecting evidence for this model at the LHC are discussed.

    hep-phPRD(2016)·1 citation
22. 22*

    Adapting the serial Alpgen event generator to simulate LHC collisions on millions of parallel threads

    J.T. Childers🇺🇸 · T.D. Uram🇺🇸 · T.J. LeCompte🇺🇸 · M.E. Papka🇺🇸 · D.P. Benjamin🇺🇸

    As the LHC moves to higher energies and luminosity, the demand for computing resources increases accordingly and will soon outpace the growth of the Worldwide LHC Computing Grid. To meet this greater demand, event generation Monte Carlo was targeted for adaptation to run on Mira, the supercomputer at the Argonne Leadership Computing Facility. Alpgen is a Monte Carlo event generation application that is used by LHC experiments in the simulation of collisions that take place in the Large Hadron Collider. This paper details the process by which Alpgen was adapted from a single-processor serial-application to a large-scale parallel-application and the performance that was achieved.

    hep-phcs.DCphysics.comp-phComput.Phys.Commun.(2017)·9 citations
23. 23*

    MSSM Higgs : Window into Susy GUTs

    Charanjit S. Aulakh🇮🇳

    The Minimal Supersymmetric SO(10) GUT has developed into a fully realistic theory in which not only are the gauge couplings unified but the known fermion spectrum and mixing matrices could fit accurately using the latitude introduced by inclusion of quantum corrections to the GUT-effective MSSM-SM matching conditions. The fits yield predictions about the nature of the sparticle spectrum on the basis of the required threshold corrections. This indicated a necessarily large value for $A_0$ in 2008 : well before Higgs discovery at 126 GeV made it a commonplace assumption. GUT scale threshold corrections to the normalization of the emergent effective MSSM Higgs ameliorate the long standing Susy GUT puzzle of fast dimension five operator mediated proton decay. Numerical investigation indicates that B-violation rates below or near the current experimental upper limits are feasible in fully realistic models. Our results imply that UV completion models with large numbers of fields, like Kaluza-Klein models or String Theory, must be able to compute threshold corrections to be considered quantitative theories and not just fables. Required improvements in the fitting procedure are discussed. A generalization of the NMSGUT by gauging the flavour symmetry of the kinetic terms,while retaining renormalizability and the successful MSGUT symmetry breaking patterns, may allow dynamical generation of the observed Yukawa structure of the MSSM via the spontaneous breaking of the full gauge symmetry down to the MSSM at the unification scale. Focus on the emergence of the MSSM Higgs from the multiple Higgs doublets in the GUT thus provides a crucial window to view the energetically remote UV dynamics specified in fully calculable and realistic MSGUTs.

    hep-phPoS(2015)·0 citations
24. 24*

    A brief theory overview of Higgs physics at the LHC

    Marius Wiesemann🇨🇭

    This is a brief review of the theoretical status of Higgs production at the LHC in the Standard Model, with an emphasis on the recent developments and computations. In particular, I focus on both inclusive and differential cross sections for the dominant production mode in the Standard Model, where the theoretical uncertainties induced by the different interplays between top- and bottom-quark effects in the gluon-fusion scattering amplitude are discussed.

    hep-phActa Phys.Polon.B(2015)·3 citations
25. 25*

    Electroweak breaking and neutrino mass: "invisible" Higgs decays at the LHC (Type II seesaw)

    Cesar Bonilla🇪🇸 · Jorge C. Romão🇵🇹 · José W.F. Valle🇪🇸

    Neutrino mass generation through the Higgs mechanism not only suggests the need to reconsider the physics of electroweak symmetry breaking from a new perspective, but also provides a new theoretically consistent and experimentally viable paradigm. We illustrate this by describing the main features of the electroweak symmetry breaking sector of the simplest type-II seesaw model with spontaneous breaking of lepton number. After reviewing the relevant "theoretical" and astrophysical restrictions on the Higgs sector, we perform an analysis of the sensitivities of Higgs boson searches at the ongoing ATLAS and CMS experiments at the LHC, including not only the new contributions to the decay channels present in the Standard Model (SM) but also genuinely non-SM Higgs boson decays, such as "invisible" Higgs boson decays to majorons. We find sensitivities that are likely to be reached at the upcoming Run of the experiments.

    hep-phNew J.Phys.(2016)·28 citations
26. 26*

    Resonance production in Pomeron-Pomeron collisions at the LHC

    R. Fiore (Univ. of Calabria, Nat. Inst. of Nucl. Phys., Cosenza)🇮🇹 · L. Jenkovszky (BITP, Kiev)🇺🇦 · R. Schicker (Phys. Inst., Univ. Heidelberg)🇩🇪

    A Regge pole model for Pomeron-Pomeron total cross section in the resonance region $\sqrt{M^2}\le$ 5 GeV is presented. The cross section is saturated by direct-channel contributions from the Pomeron as well as from two different $f$ trajectories, accompanied by the isolated f${}_0(500)$ resonance which dominates the $\sqrt{M^2}\lesssim 1$ GeV region. A slowly varying background is taken into account. The calculated Pomeron-Pomeron total cross section cannot be measured directly, but is an essential part of central diffractive processes. In preparation of future calculations of central resonance production at the hadron level, and corresponding measurements at the LHC, we normalize the Pomeron-Pomeron cross section at large masses ${\sigma }_t^{PP}(\sqrt{M^2}\to \infty )\approx$ 1 mb as suggested by QCD-motivated estimates.

    hep-phhep-exEPJC(2016)·30 citations
27. 27*

    Single top quark production at the LHC

    Andrea Giammanco🇧🇪

    This paper is an experimental review of the study of processes with a single top quark at the LHC. The pioneering times are over, and this is now a sector of "precision physics" at colliders. Angular distributions of the decay products of singly-produced top quarks are unique tests of the electroweak interaction. Searches for rare final states of the form t+X (where X=$\gamma$, Z, H) are very sensitive to new physics, and will enter with Run II in a very interesting zone of the parameter space of some theories. The relative sign of the Yukawa coupling of the top quark with respect to the Higgs coupling to gauge bosons will be conclusively measured very soon in the tHq final state.

    ↳ hep-exhep-phRev.Phys.(2016)·41 citations
28. 28*

    The IR Obstruction to UV Completion for Dante's Inferno Model with Higher-Dimensional Gauge Theory Origin

    Kazuyuki Furuuchi🇮🇳 · Yoji Koyama🇹🇼

    We continue our investigation of large field inflation models obtained from higher-dimensional gauge theories, initiated in our previous study arXiv:1407.1951. We focus on Dante's Inferno model which was the most preferred model in our previous analysis. We point out the relevance of the IR obstruction to UV completion, which constrains the form of the potential of the massive vector field, under the current observational upper bound on the tensor to scalar ratio. We also show that in simple examples of the potential arising from DBI action of a D5-brane and that of an NS5-brane that the inflation takes place in the field range which is within the convergence radius of the Taylor expansion. This is in contrast to the well known examples of axion monodromy inflation where inflaton takes place outside the convergence radius of the Taylor expansion. This difference arises from the very essence of Dante's Inferno model that the effective inflaton potential is stretched in the inflaton field direction compared with the potential for the original field.

    ↳ hep-thastro-ph.COhep-phJCAP(2016)·3 citations
29. 29*

    LQCD: Flavor Physics and Spectroscopy

    Carleton DeTar🇺🇸

    I review highlights of recent results in quark-flavor physics and heavy-quark spectroscopy from lattice QCD, with emphasis on $B$-meson decays and excited and exotic charmonium states.

    ↳ hep-lathep-exhep-phPoS(2016)·18 citations
30. 30*

    Notes on Translational and Rotational Properties of Tensor Fields in Relativistic Quantum Mechanics

    Valeriy V. Dvoeglazov🇲🇽

    Recently, several discussions on the possible observability of 4-vector fields have been published in literature. Furthermore, several authors recently claimed existence of the helicity=0 fundamental field. We re-examine the theory of antisymmetric tensor fields and 4-vector potentials. We study the massless limits. In fact, a theoretical motivation for this venture is the old papers of Ogievetskii and Polubarinov, Hayashi, and Kalb and Ramond. They proposed the concept of the notoph, whose helicity properties are complementary to those of the photon. We analyze the quantum field theory with taking into account mass dimensions of the notoph and the photon. It appears to be possible to describe both photon and notoph degrees of freedom on the basis of the modified Bargmann-Wigner formalism for the symmetric second-rank spinor. Next, we proceed to derive equations for the symmetric tensor of the second rank on the basis of the Bargmann-Wigner formalism in a straightforward way. The symmetric multispinor of the fourth rank is used. Due to serious problems with the interpretation of the results obtained on using the standard procedure we generalize it and obtain the spin-2 relativistic equations, which are consistent with the general relativity. Thus, in fact we deduced the gravitational field equations from relativistic quantum mechanics. The relations of this theory with the scalar-tensor theories of gravitation and f(R) are discussed. Particular attention has been paid to the correct definitions of the energy-momentum tensor and other Noether currents in the electromagnetic theory, the relativistic theory of gravitation, the general relativity, and their generalizations. We estimate possible interactions, fermion-notoph, graviton-notoph, photon-notoph, and we conclude that they can probably be seen in experiments in the next few years.

    ↳ hep-thgr-qchep-phmath-ph+1Adv.Appl.Clifford Algebras(2017)·0 citations
31. 31*

    Rényi entropy and the thermodynamic stability of black holes

    Viktor G. Czinner🇯🇵 · Hideo Iguchi🇯🇵

    Thermodynamic stability of black holes, described by the Rényi formula as equilibrium compatible entropy function, is investigated. It is shown that within this approach, asymptotically flat, Schwarzschild black holes can be in stable equilibrium with thermal radiation at a fixed temperature. This implies that the canonical ensemble exists just like in anti-de Sitter space, and nonextensive effects can stabilize the black holes in a very similar way as it is done by the gravitational potential of an anti-de Sitter space. Furthermore, it is also shown that a Hawking-Page-like black hole phase transition occurs at a critical temperature which depends on the $q$-parameter of the Rényi formula.

    ↳ gr-qccond-mat.stat-mechhep-phhep-thPLB(2016)·186 citations
32. 32*

    Entanglement of Dirac bi-spinor states driven by Poincaré classes of $\text{mbox}SU(2)\otimes \text{mbox}SU(2)$ coupling potentials

    Victor A. S. V. Bittencourt🇧🇷 · Alex E. Bernardini🇧🇷

    A generalized description of entanglement and quantum correlation properties constraining internal degrees of freedom of Dirac(-like) structures driven by arbitrary Poincaré classes of external field potentials is proposed. The role of (pseudo)scalar, (pseudo)vector and tensor interactions in producing/destroying intrinsic quantum correlations for $\text{mbox}SU(2)\otimes \text{mbox}SU(2)$ bi-spinor structures is discussed in terms of generic coupling constants. By using a suitable ansatz to obtain the Dirac Hamiltonian eigenspinor structure of time-independent solutions of the associated Liouville equation, the quantum entanglement, via concurrence, and quantum correlations, via geometric discord, are computed for several combinations of well-defined Poincaré classes of Dirac potentials. Besides its inherent formal structure, our results setup a framework which can be enlarged as to include localization effects and to map quantum correlation effects into Dirac-like systems which describe low-energy excitations of graphene and trapped ions.

    ↳ quant-phhep-phAnnals Phys.(2016)·24 citations
33. 33*

    Vector theory of gravity: Universe without black holes and solution of dark energy problem

    Anatoly A. Svidzinsky🇺🇸

    We propose an alternative theory of gravity which assumes that background geometry of the Universe is fixed four dimensional Euclidean space and gravity is a vector field $A_k$ in this space which breaks the Euclidean symmetry. Direction of $A_k$ gives the time coordinate, while perpendicular directions are spatial coordinates. Vector gravitational field is coupled to matter universally and minimally through the equivalent metric $f_{ik}$ which is a functional of $A_k$. We show that such assumptions yield a unique theory of gravity, it is free of black holes and, to the best of our knowledge, passes all available tests. For cosmology our theory predicts the same evolution of the Universe as general relativity with cosmological constant and zero spatial curvature. However, the present theory provides explanation of the dark energy as energy of longitudinal gravitational field induced by the Universe expansion and yields, with no free parameters, the value of ${\Omega }_{\Lambda }=2/3\approx 0.67$ which agrees with the recent Planck result ${\Omega }_{\Lambda }=0.686\pm 0.02$. Such striking agreement indicates that gravity has a vector, rather than tensor, origin. We demonstrate that gravitational wave signals measured by LIGO are compatible with vector gravity. They are produced by orbital inspiral of massive neutron stars which can exist in the present theory. We also quantize gravitational field and show that quantum vector gravity is equivalent to QED. Vector gravity can be tested by making more accurate measurement of the time delay of radar signal traveling near the Sun; by improving accuracy of the light deflection experiments; or by measuring propagation direction of gravitational waves relative to laser interferometer arms. Resolving the supermassive object at the center of our Galaxy with VLBA could provide another test of gravity and also shed light on the nature of dark matter.

    ↳ gr-qcastro-ph.COastro-ph.HEhep-ph+1Phys.Scripta(2017)·20 citations
34. 34*

    The $K^{\ast 0}\Lambda$ photoproduction off a neutron

    Xiao-Yun Wang🇨🇳 · Jun He🇨🇳

    Inspired by the preliminary experimental data by the CLAS Collaboration, the $K^{\ast 0}\Lambda$ photoproduction off a neutron is studied within an effective Lagrangian approach. The contributions from the Born terms including $s$, $u$, and $t$ channels are considered to calculate the amplitude, with which the cross sections are calculated and compared with preliminary CLAS data. The theoretical results indicate that the contribution from the $K$-exchange $t$ channel plays a dominant role for the $K^{\ast 0}\Lambda$ photoproduction. The contribution from the $\kappa$ exchange is found one order of magnitude smaller than that from the $K$ exchange. Both the Regge model and the Feynman model are applied to treat the $t$-channel contribution. The discrepancy between two models is found small in the energy range of CLAS data and predicted to become obvious at energies higher than 3 GeV. More precise experimental data especially at backward angles will be helpful to further understand the interaction mechanism of the $K^{\ast 0}\Lambda$ photoproduction.

    ↳ nucl-thhep-phnucl-exPRC(2016)·17 citations
35. 35*

    Sensitivity of the JEM-EUSO telescope to gravity effects in neutrino-induced air showers

    Stefan Mladenov🇧🇬 · Galina Vankova🇧🇬 · Roumen Tsenov🇧🇬 · Mario Bertaina🇮🇹 · Andrea Santangelo🇩🇪

    We examine the JEM-EUSO sensitivity to gravity effects in the context of Randall-Sundrum (RS) model with a single extra dimension and small curvature of the metric. Exchanges of reggeized Kaluza-Klein gravitons in the $t$-channel contribute to the inelastic cross-section for scattering of ultra-high-energy neutrinos off nucleons. Such effects can be detected in deeply penetrating quasi-horizontal air showers induced by interactions of cosmic neutrinos with atmospheric nucleons. For this reason, we calculate the expected number of quasi-horizontal air showers at the JEM-EUSO observatory as a function of two parameters of the RS model.

    ↳ astro-ph.HEhep-ph0 citations
36. 36*

    Hydrodynamical noise and Gubser flow

    Li Yan🇫🇷 · Hanna Grönqvist🇫🇷

    Hydrodynamical noise is introduced on top of Gubser's analytical solution to viscous hydrodynamics. With respect to the ultra-central collision events of Pb-Pb, p-Pb and p-p at the LHC energies, we solve the evolution of noisy fluid systems and calculate the radial flow velocity correlations. We show that the absolute amplitude of the hydrodynamical noise is determined by the multiplicity of the collision event. The evolution of azimuthal anisotropies, which is related to the generation of harmonic flow, receives finite enhancements from hydrodynamical noise. Although it is strongest in the p-p systems, the effect of hydrodynamical noise on flow harmonics is found to be negligible, especially in the ultra-central Pb-Pb collisions. For the short-range correlations, hydrodynamical noise contributes to the formation of a near-side peak on top of the correlation structure originated from initial state fluctuations. The shape of the peak is affected by the strength of hydrodynamical noise, whose height and width grow from the Pb-Pb system to the p-Pb and p-p systems.

    ↳ nucl-thhep-phnucl-exJHEP(2016)·31 citations
37. 37*

    Scalar-Tensor Quintessence with a linear potential: Avoiding the Big Crunch cosmic doomsday

    A. Lykkas🇬🇷 · L. Perivolaropoulos🇬🇷

    All quintessence potentials that are either monotonic with negative interval or have a minimum at negative values of the potential, generically predict a future collapse of the scale factor to a "doomsday" singularity. We show that this doomsday is generically avoided in models with a proper non-minimal coupling of the quintessence scalar field to the curvature scalar $R$. For simplicity we consider linear quintessence potential $V=-s\varphi$ and linear non-minimal coupling $F=1-\lambda \varphi$. However our result is generic and is due to the fact that the non-minimal coupling modifies the effective potential that determines the dynamics of the scalar field. Thus for each positive value of the parameter $s$ we find a critical value ${\lambda }_{crit}(s)$ such that for $\lambda >{\lambda }_{crit}(s)$ the negative potential energy does not dominate the universe and the cosmic doomsday Big Crunch singularity is avoided because the scalar field eventually rolls up its potential. We find that ${\lambda }_{crit}(s)$ increases approximately linearly with $s$. For $\lambda >{\lambda }_{crit}(s)$ the potential energy of the scalar field becomes positive and it eventually dominates while the dark energy equation of state parameter tends to $w=-1$ leading to a deSitter Universe.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2016)·16 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.