Thu·Aug 13, 2015Thursday·August 13, 2015

1. 01*

   Exclusive decays $B\to {\ell }^{-}\bar{\nu }$ and $B\to D^{(\ast )}{\ell }^{-}\bar{\nu }$ in the covariant quark model

   Mikhail A. Ivanov🇷🇺 · Jürgen G. Körner🇩🇪 · Chien-Thang Tran🇷🇺

   We study the exclusive leptonic and semileptonic $B$ decays $B\to {\ell }^{-}\bar{\nu }$ and $B\to D^{(\ast )}{\ell }^{-}\bar{\nu }$ in the framework of the covariant quark model with built-in infrared confinement. We compute the relevant form factors in the full kinematical momentum transfer region. The calculated form factors are used to evaluate branching fractions and polarization observables of the above transitions. We compare our results with experimental data and results from other theoretical studies.

   hep-phhep-exnucl-thPRD(2015)·71 citations
2. 02*

   Four-loop strong coupling beta-function in the Standard Model

   A.V. Bednyakov🇷🇺 · A.F. Pikelner🇩🇪

   In this letter we present our results for the four-loop beta-function of the strong coupling in the Standard Model of fundamental interactions. We take top-Yukawa and self-Higgs interactions into account, but neglect electroweak gauge couplings.

   hep-phhep-thPLB(2016)·67 citations
3. 03*

   Fiducial cross sections for Higgs boson production in association with a jet at next-to-next-to-leading order in QCD

   Fabrizio Caola🇨🇭 · Kirill Melnikov🇩🇪 · Markus Schulze🇨🇭

   We extend the recent computation of Higgs boson production in association with a jet through next-to-next-to-leading order in perturbative QCD by including decays of the Higgs boson to electroweak vector bosons. This allows us to compute fiducial cross sections and kinematic distributions including realistic selection criteria for the Higgs boson decay products. As an illustration, we present results for $pp\to H+j\to \gamma \gamma +j$ closely following the ATLAS 8 TeV analysis and for $pp\to H+j\to WW+j\to e^{+}{\mu }^{-}\nu \bar{\nu }+j$ in a CMS-like 13 TeV setup.

   hep-phhep-exPRD(2015)·104 citations
4. 04*

   Exclusive physics at the LHC with SuperChic 2

   L. A. Harland-Lang🇬🇧 · V. A. Khoze🇬🇧 · M. G. Ryskin🇷🇺

   We present a range of physics results for central exclusive production processes at the LHC, using the new SuperChic 2 Monte Carlo event generator. This includes significant theoretical improvements and updates, most importantly a fully differential treatment of the soft survival factor, as well as a greater number of generated processes. We provide an overview of the latest theoretical framework, and consider in detail a selection of final states, namely exclusive 2 and 3 jets, photoproduced vector mesons, two-photon initiated muon and $W$ boson pairs and heavy ${\chi }_{c,b}$ quarkonia.

   hep-phEPJC(2016)·131 citations
5. 05*

   Neutrino mass determination using circulating heavy ions

   M. Yoshimura🇯🇵

   We study process of radiative neutrino pair emission $|e⟩\to |g⟩+\gamma +\nu \bar{\nu }$ from coherently excited heavy ions (quantum mixture of two ionic states, the ground and an excited states) in circular motion. Determination of the neutrino mass is found to be possible with simultaneous detection of the photon and one of neutrinos in the pair down to the level of the smallest neutrino mass of order 5 meV in the three flavor scheme.

   hep-phhep-exPRD(2016)·1 citation
6. 06*

   Higgs-bosons couplings to quarks and leptons in the supersymmetric Standard Model with a gauge singlet

   Andreas Crivellin🇨🇭 · Youichi Yamada🇯🇵

   The loop corrections to the couplings of Higgs bosons to quarks and charged leptons are calculated within supersymmetric versions of the Standard Model, extended by a gauge singlet. The effective couplings of the $SU(2{)}_L$ doublet and singlet Higgs bosons to quarks and leptons, induced by sfermion loops, are derived. Analytic expressions for the case of generic sfermion flavour mixing, including the complete resummation of all chirally-enhanced contributions are presented. These results are important in scenarios in which the mixing between singlet and doublet components of Higgs bosons is small, and the (pseudo) scalar component of the doublet is light. The calculated loop effects can have important consequences in flavour physics, especially for $\Delta F=2$ processes.

   hep-phJHEP(2015)·3 citations
7. 07*

   Generation of narrow peaks in charged-particle magnetic spectroscopy

   Dirk Dubbers🇩🇪

   In spectroscopy of charged particles, narrow peaks may appear in initially smooth continuous spectra if magnetic transport of the particles is involved. As such unexpected peaks may be misinterpreted as new physics, their generation is investigated for various experimental configurations.

   hep-phphysics.ins-det0 citations
8. 08*

   Electroweak interacting dark matter with a singlet scalar portal

   Cheng-Wei Chiang🇹🇼 · Eibun Senaha🇹🇼

   We investigate an electroweak interacting dark matter (DM) model in which the DM is the neutral component of the SU$(2{)}_L$ triplet fermion that couples to the standard model (SM) Higgs sector via an SM singlet Higgs boson. In this setup, the DM can have a CP-violating coupling to the singlet Higgs boson at the renormalizable level. As long as the nonzero Higgs portal coupling (singlet-doublet Higgs boson mixing) exists, we can probe CP violation of the DM via the electric dipole moment of the electron. Assuming the $\mathcal{O}(1)$ CP-violating phase in magnitude, we investigate the relationship between the electron EDM and the singlet-like Higgs boson mass and coupling. It is found that for moderate values of the Higgs portal couplings, current experimental EDM bound is not able to exclude the wide parameter space due to a cancellation mechanism at work. We also study the spin-independent cross section of the DM in this model. It is found that although a similar cancellation mechanism may diminish the leading-order correction, as often occurs in the ordinary Higgs portal DM scenarios, the residual higher-order effects leave an $\mathcal{O}(10^{-47}){\mathrm{cm}}^2$ correction in the cancellation region. It is shown that our benchmark scenarios would be fully tested by combining all future experiments of the electron EDM, DM direct detection and Higgs physics.

   hep-phPLB(2015)·7 citations
9. 09*

   Light Pseudoscalar Mesons in Bethe-Salpeter Equation with Instantaneous Interaction

   Wolfgang Lucha🇦🇹 · Franz F. Schöberl🇦🇹

   The light pseudoscalar mesons play a twofold role: they may or have to be regarded both as low-lying bound states of the fundamental degrees of freedom of quantum chromodynamics as well as the (pseudo-) Goldstone bosons of the spontaneously broken chiral symmetries of quantum chromodynamics. We interrelate these aspects in a single quantum-field-theoretic approach relying on the Bethe-Salpeter formalism in instantaneous approximation by very simple means: the shape of the pseudoscalar-meson Bethe-Salpeter wave function dictated by chiral symmetry is used in Bethe-Salpeter equations for bound states of vanishing mass, in order to deduce analytically the interactions which govern the bound states under study. In this way, we obtain exact Bethe-Salpeter solutions for pseudoscalar mesons, in the sense of establishing the rigorous relationship between, on the one hand, the relevant interactions and, on the other hand, the Bethe-Salpeter amplitudes that characterize the bound states.

   hep-phnucl-thPRD(2015)·11 citations
10. 10*

    Study of anomalous tau lepton decay using chiral Lagrangian with vector mesons

    Takuya Morozumi🇯🇵 · Hiroyuki Umeeda (Hiroshima University)🇯🇵 · Daiji Kimura (Ube National College of Technology)🇯🇵

    An intrinsic parity violating hadronic tau lepton decay is investigated. $\tau \to \pi \pi \eta \nu$ is the process in which the dominant contribution to the amplitude is due to the intrinsic parity violation. To predict the hadronic invariant mass spectra and to compare them with experimental data, we extend the chiral Lagrangian with vector mesons so that it incorporates the intrinsic parity violating terms and $\varphi$ and ${\eta }^{\prime }$ mesons. The coefficients of the intrinsic parity violating terms will be determined by fitting the branching fractions for $V^I\to P\gamma$, $V^I\to 3P$ and $P\to V^I\gamma$ where $V^I$ denotes vector mesons $1^{-}$ and $P$ denotes pseudo-scalar mesons $0^{-}$.

    hep-phhep-exPoS(2015)·0 citations
11. 11*

    Effects of Cosmic String Velocities and the Origin of Globular Clusters

    Ling Lin🇨🇦 · Shoma Yamanouchi🇨🇦 · Robert Brandenberger (McGill University)🇨🇦

    With the hypothesis that cosmic string loops act as seeds for globular clusters in mind, we study the role that velocities of these strings will play in determining the mass distribution of globular clusters. Loops with high enough velocities will not form compact and roughly spherical objects and can hence not be the seeds for globular clusters. We compute the expected number density and mass function of globular clusters as a function of both the string tension and the peak loop velocity, and compare the results with the observational data on the mass distribution of globular clusters in our Milky Way. We determine the critical peak string loop velocity above which the agreement between the string loop model for the origin of globular clusters (neglecting loop velocities) and observational data is lost.

    ↳ astro-ph.COastro-ph.GAgr-qchep-ph+1JCAP(2015)·9 citations
12. 12*

    BFKL pomeron in the next-to-next-to-leading approximation in the planar N=4 SYM theory

    V.N. Velizhanin🇩🇪

    We find the eigenvalue of the kernel of BFKL equation in the next-to-next-to-leading logarithm approximation in the planar N=4 SM theory from the constraints, coming from the six-loop anomalous dimension of twist-2 operators and known large-gamma limit.

    ↳ hep-thhep-exhep-ph31 citations
13. 13*

    Resonant-bar detectors of gravitational wave as possible probe of the noncommutative structure of space

    Anirban Saha🇮🇳 · Sunandan Gangopadhyay🇮🇳

    We report the plausibility of using quantum mechanical transitions, induced by the combined effect of Gravitational wave (GW) and noncommutative (NC) structure of space, among the states of a 2-dimensional harmonic oscillator, to probe the spatial NC geometry. The phonon modes excited by the passing GW within the resonant bar-detector are formally identical to forced harmonic oscillator and they represent a length variation of roughly the same order of magnitude as the characteristic length-scale of spatial noncommutativity estimated from the phenomenological upper bound of the NC parameter. This motivates our present work. We employ various GW wave-forms that are typically expected from possible astronomical sources. We find that the transition probablities are quite sensitive to the nature of polarization of the GW. We also elaborate on the particular type of sources of GW, radiation from which can induce transitions that can be used as effective probe of the spatial noncommutative structure.

    ↳ gr-qcastro-ph.HEhep-phhep-th+1Class.Quant.Grav.(2016)·17 citations
14. 14*

    High Energy Positrons and Gamma Radiation from Decaying Constituents of a two-component Dark Atom Model

    K. Belotsky🇷🇺 · M. Khlopov🇫🇷 · C. Kouvaris🇩🇰 · M. Laletin🇷🇺

    We study a two component dark matter candidate inspired by the Minimal Walking Technicolor model. Dark matter consists of a dominant SIMP-like dark atom component made of bound states between primordial helium nuclei and a doubly charged technilepton, and a small WIMP-like component made of another dark atom bound state between a doubly charged technibaryon and a technilepton. This scenario is consistent with direct search experimental findings because the dominant SIMP component interacts too strongly to reach the depths of current detectors with sufficient energy to recoil and the WIMP-like component is too small to cause significant amount of events. In this context a metastable technibaryon that decays to $e^{+}{e}^{+}$, ${\mu }^{+}{\mu }^{+}$ and ${\tau }^{+}{\tau }^{+}$ can in principle explain the observed positron excess by AMS-02 and PAMELA, while being consistent with the photon flux observed by FERMI/LAT. We scan the parameters of the model and we find the best possible fit to the latest experimental data. We find that there is a small range of parameter space that this scenario can be realised under certain conditions regarding the cosmic ray propagation and the final state radiation. This range of parameters fall inside the region where the current run of LHC can probe, and therefore it will soon be possible to either verify or exclude conclusively this model of dark matter.

    ↳ astro-ph.HEhep-phInt.J.Mod.Phys.D(2015)·18 citations
15. 15*

    Can we decide whether QCD is confining or not at high temperature?

    L. Ya. Glozman🇦🇹

    At high temperature measurements of the Polyakov loop suggest a deconfinement transition to the (strongly interacting) quark-gluon plasma. At the same time at the infinitely large temperature the four-dimensional QCD is reduced to the three-dimensional QCD that is confining. The Polyakov loop and related Z_3 symmetry are strict order parameters only for infinitely heavy quarks. In such a situation the SU(2)_CS and SU(4) symmetries of confinement in the light quark sector could be helpful to distinguish between the confining and deconfining phase in a regime where SU(2)_L \times SU(2)_R and U(1)_A symmetries are manifest. In order to reveal a presence or absence of these symmetries one needs to measure and compare correlation functions related by these symmetry transformations.

    ↳ hep-lathep-phhep-thnucl-th1 citation
16. 16*

    Scale invariant Volkov-Akulov Supergravity

    S. Ferrara🇨🇭 · M. Porrati🇨🇭 · A. Sagnotti🇨🇭

    A scale invariant Goldstino theory coupled to Supergravity is obtained as a standard supergravity dual of a rigidly scale invariant higher--curvature Supergravity with a nilpotent chiral scalar curvature. The bosonic part of this theory describes a massless scalaron and a massive axion in a de Sitter Universe.

    ↳ hep-thhep-phPLB(2015)·42 citations
17. 17*

    Scalar and tensor perturbations in loop quantum cosmology: High-order corrections

    Tao Zhu🇺🇸 · Anzhong Wang🇨🇳 · Gerald Cleaver🇺🇸 · Klaus Kirsten🇺🇸 · Qin Sheng🇺🇸 · Qiang Wu🇨🇳

    Loop quantum cosmology (LQC) provides promising resolutions to the trans-Planckian issue and initial singularity arising in the inflationary models of general relativity. In general, due to different quantization approaches, LQC involves two types of quantum corrections, the holonomy and inverse-volume, to both of the cosmological background evolution and perturbations. In this paper, using {\em the third-order uniform asymptotic approximations}, we derive explicitly the observational quantities of the slow-roll inflation in the framework of LQC with these quantum corrections. We calculate the power spectra, spectral indices, and running of the spectral indices for both scalar and tensor perturbations, whereby the tensor-to-scalar ratio is obtained. We expand all the observables at the time when the inflationary mode crosses the Hubble horizon. As the upper error bounds for the uniform asymptotic approximation at the third-order are $\lesssim 0.15\%$, these results represent the most accurate results obtained so far in the literature. It is also shown that with the inverse-volume corrections, both scalar and tensor spectra exhibit a deviation from the usual shape at large scales. Then, using the Planck, BAO and SN data we obtain new constraints on quantum gravitational effects from LQC corrections, and find that such effects could be within the detection of the forthcoming experiments.

    ↳ gr-qcastro-ph.COhep-phhep-thJCAP(2015)·28 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.