Mon·Dec 11, 2017Monday·December 11, 2017

1. 01*

   What is the right formalism to search for resonances?

   JPAC Collaboration: M. Mikhasenko🇩🇪 · A. Pilloni🇺🇸 · J. Nys🇧🇪 · M. Albaladejo🇪🇸 · C. Fernandez-Ramirez🇲🇽 · A. Jackura🇺🇸 · V. Mathieu🇺🇸 · N. Sherrill🇺🇸 · T. Skwarnicki🇺🇸 · A. P. Szczepaniak🇺🇸

   Hadron decay chains constitute one of the main sources of information on the QCD spectrum. We discuss the differences between several partial wave analysis formalisms used in the literature to build the amplitudes. We match the helicity amplitudes to the covariant tensor basis. Hereby, we pay attention to the analytical properties of the amplitudes and separate singularities of kinematical and dynamical nature. We study the analytical properties of the spin-orbit (LS) formalism, and some of the covariant tensor approaches. In particular, we explicitly build the amplitudes for the B -> psi pi K and B -> Dbar pi pi decays, and show that the energy dependence of the covariant approach is model dependent. We also show that the usual recursive construction of covariant tensors explicitly violates crossing symmetry, which would lead to different resonance parameters extracted from scattering and decay processes.

   hep-phhep-exnucl-thEPJC(2018)·20 citations
2. 02*

   Parton correlations in double parton scattering

   Tomas Kasemets🇩🇪 · Sergio Scopetta🇮🇹

   Double parton scattering events are directly sensitive to the correlations between two partons inside a proton and can answer fundamental questions on the connections between the proton constituents. In this chapter, the different types of possible correlations, our present knowledge of them, and the processes where they are likely to be important, are introduced and explained. The increasing integrated luminosity at the LHC and the refinements of the theory of double parton scattering, lead to interesting prospects for measuring, or severely constraining, two-parton correlations in the near future.

   hep-phnucl-thAdv.Ser.Direct.High Energy Phys.(2018)·22 citations
3. 03*

   Nonperturbative QCD thermodynamics in the external magnetic field

   M.A. Andreichikov🇷🇺 · Yu.A. Simonov🇷🇺

   The thermodynamics of quarks and gluons strongly depends on the vacuum colormagnetic field, which grows with the temperature $T$, so that spatial string tension ${\sigma }_s=\mathrm{const}{g}^4(T)T^2$. We investigate below what happens when one imposes in addition constant magnetic field and discover remarkable structure of the resulting thermodynamic potential.

   hep-phEPJC(2018)·12 citations
4. 04*

   Effective theory approach to direct detection of dark matter

   Junji Hisano🇯🇵

   An effective field theory approach is presented for evaluation of the dark matter direct detection rate in this lecture note. This is prepared for the Les Houches Summer School Effective Field Theory in Particle Physics and Cosmology, July 2017.

   hep-phLes Houches Lect.Notes(2020)·19 citations
5. 05*

   Study of $B_c\to \psi (2S)K$, ${\eta }_c(2S)K$, $\psi (3770)K$ decays with perturbative QCD approach

   Feng Bo Duan🇨🇳 · Xian-Qiao Yu🇨🇳

   We study the $B_c$$\to$$\psi (2S)$K, ${\eta }_c(2S)$K, $\psi (3770)$K decays with perturbative QCD approach (pQCD) based on $k_T$ factorization. The new orbitally excited charmonium distribution amplitudes $\psi (1^3{D}_1)$ based on the Schrödinger wave function of the $n=1$, $l=2$ state for the harmonic-oscillator potential are employed. By using the corresponding distribution amplitudes, we calculate the branching ratio of $B_c$$\to$$\psi (2S)$K, ${\eta }_c(2S)$K, $\psi (3770)$K decays and the form factors $A_{0,1,2}$ and $V$ for the transition $B_c$$\to$$\psi (1^3{D}_1)$. We obtain the branching ratio of both $B_c$$\to$$\psi (2S)$K and $B_c$$\to$${\eta }_c(2S)$K are at the order of $10^{-5}$. The effects of two sets of the S-D mixing angle $\theta =-12^{\circ }$ and $\theta =27^{\circ }$ for the decay $B_c$$\to$$\psi (3770)$K are studied firstly in this paper. Our calculations show that the branching ratio of the decay $B_c$$\to$$\psi (3770)$K can be raised from the order of $10^{-6}$ to the order of $10^{-5}$ at the mixing angle $\theta =-12^{\circ }$, which can be tested by the running LHC-b experiments.

   hep-phPRD(2018)·3 citations
6. 06*

   Dark matter assisted Dirac leptogenesis and neutrino mass

   Nimmala Narendra🇮🇳 · Nirakar Sahoo🇮🇳 · Narendra Sahu🇮🇳

   We propose a minimal extension of the standard model with U(1)_{B-L} \times Z_{2} symmetry. In this model by assuming that the neutrinos are Dirac (i.e. $B-L$ is an exact symmetry), we found a simultaneous solution for non zero neutrino masses and dark matter content of the universe. The observed baryon asymmetry of the universe is also explained using Dirac Leptogenesis, which is assisted by a dark sector, gauged under a U(1)_D symmetry. The latter symmetry of the dark sector is broken at a TeV scale and thereby giving mass to a neutral gauge boson Z_D. The standard model Z-boson mixes with the gauge boson Z_D at one loop level and thus paves a way to detect the dark matter through spin independent elastic scattering at terrestrial laboratories.

   hep-phNPB(2018)·32 citations
7. 07*

   Axions and ALPs: a very short introduction

   David J. E. Marsh🇬🇧

   The QCD axion was originally predicted as a dynamical solution to the strong CP problem. Axion like particles (ALPs) are also a generic prediction of many high energy physics models including string theory. Theoretical models for axions are reviewed, giving a generic multi-axion action with couplings to the standard model. The couplings and masses of these axions can span many orders of magnitude, and cosmology leads us to consider several distinct populations of axions behaving as coherent condensates, or relativistic particles. Light, stable axions are a mainstay dark matter candidate. Axion cosmology and calculation of the relic density are reviewed. A very brief survey is given of the phenomenology of axions arising from their direct couplings to the standard model, and their distinctive gravitational interactions.

   hep-phastro-ph.COhep-th57 citations
8. 08*

   On the impact of off-shell contributions on the top quark mass extraction in ttj events

   Manfred Kraus🇩🇪

   In this contribution we present a systematic comparison of the full off-shell calculation for pp -> ttj in the dileptonic decay channel with a description based on the narrow width approximation. The aim of this study is to estimate the size of off-shell and non-resonant contributions to the shape of differential distributions, that will be utilized in the top quark mass extraction using the template fit method.

   hep-phPoS(2017)·0 citations
9. 09*

   Estimate of the Abelian Z' boson decay width

   A. Pevzner🇺🇦

   The Abelian $Z^{\prime }$ boson decay width is calculated in a model-independent approach. The analysis takes into consideration the special relations between the $Z^{\prime }$ couplings to the Standard model fields proper to the renormalizable theories. The constraints on the $Z^{\prime }$ couplings to the Standard model fermions corresponding to the narrow width approximation are derived. The results are compared with the benchmark $Z^{\prime }$ models, such as $Z_{\chi }^{\prime }$ and $LR$. It is shown that the current experimental limits on the Standard model $Z$ width impose no limits on the $Z^{\prime }$ width, so that the ratio ${\Gamma }_{Z^{\prime }}/m_{Z^{\prime }}$ is allowed to be up to 100%. This fact is connected with the smallness of the $Z-Z^{\prime }$ mixing. So, the finite-width $Z^{\prime }$ is admitted and cannot be excluded from consideration. Also, the new constraints on the $Z-Z^{\prime }$ mixing angle are derived which agree with the corresponding earlier results of the LEP data analysis.

   hep-phVisnik Dniprov'skogo universitetu. Seria …·1 citation
10. 10*

    All-optical signatures of Strong-Field QED in the vacuum emission picture

    Holger Gies🇩🇪 · Felix Karbstein🇩🇪 · Christian Kohlfürst🇩🇪

    We study all-optical signatures of the effective nonlinear couplings among electromagnetic fields in the quantum vacuum, using the collision of two focused high-intensity laser pulses as an example. The experimental signatures of quantum vacuum nonlinearities are encoded in signal photons, whose kinematic and polarization properties differ from the photons constituting the macroscopic laser fields. We implement an efficient numerical algorithm allowing for the theoretical investigation of such signatures in realistic field configurations accessible in experiment. This algorithm is based on a vacuum emission scheme and can readily be adapted to the collision of more laser beams or further involved field configurations. We solve the case of two colliding pulses in full 3+1 dimensional spacetime, and identify experimental geometries and parameter regimes with improved signal-to-noise ratios.

    hep-phhep-thquant-phPRD(2018)·69 citations
11. 11*

    Analysis of $D_{s}D{K}^{\ast }$ and $D_s{D}^{\ast }{K}^{\ast }$ vertices and branching ratio of $B^{+}\to {K^{\ast }}^0{\pi }^{+}$

    M. Janbazi🇮🇷 · R. Khosravi🇮🇷

    In this paper, the strong form factors and coupling constants of $D_{s}D{K}^{\ast }$ and $D_s{D}^{\ast }{K}^{\ast }$ vertices are investigated within the three-point QCD sum rules method with and without the $S{U}_f(3)$ symmetry. In this calculation, the contributions of the quark-quark, quark-gluon, and gluon-gluon condensate corrections are considered. As an example of specific application of these coupling constants, the branching ratio of the hadronic decay $B^{+}\to {K^{\ast }}^0{\pi }^{+}$ is analyzed based on the one-particle-exchange which is one of the phenomenological models. In this model, $B$ decays into a $D_s{D}^{\ast }$ intermediate state, and then these two particles exchange a $D(D^{\ast })$ producing the final $K^{\ast }$ and $\pi$ mesons. In order to compute the effect of these interactions, the $D_{s}D{K}^{\ast }$ and $D_s{D}^{\ast }{K}^{\ast }$ form factors are needed.

    hep-phEPJC(2018)·13 citations
12. 12*

    Weak Decays of Doubly Heavy Baryons: Multi-body Decay Channels

    Yu-Ji Shi🇨🇳 · Wei Wang🇨🇳 · Ye Xing🇨🇳 · Ji Xu🇨🇳

    The newly-discovered ${\Xi }_{cc}^{++}$ decays into the ${\Lambda }_c^{+}{K}^{-}{\pi }^{+}{\pi }^{+}$, but the experimental data has indicated that this decay is not saturated by any two-body intermediate state. In this work, we analyze the multi-body weak decays of doubly heavy baryons ${\Xi }_{cc}$, ${\Omega }_{cc}$, ${\Xi }_{bc}$, ${\Omega }_{bc}$, ${\Xi }_{bb}$ and ${\Omega }_{bb}$, in particular the three-body nonleptonic decays and four-body semileptonic decays. We classify various decay modes according to the quark-level transitions and present an estimate of the typical branching fractions for a few golden decay channels. Decay amplitudes are then parametrized in terms of a few SU(3) irreducible amplitudes. With these amplitudes, we find a number of relations for decay widths, which can be examined in future.

    hep-phEPJC(2018)·89 citations
13. 13*

    Precision Physics at LEP

    Siegfried Bethke🇩🇪

    As a part of the homage on Guido Altarelli, summarised in the book "From my vast repertoire - the legacy of Guido Altarelli" edited by S. Forte, A. Levy and G. Ridolfi, this contribution collects some of the technological and scientific highlights of precision physics at LEP, the Large Electron-Positron collider operated, from 1989 to 2000, at the European Laboratory for Particle Physics, CERN.

    ↳ hep-exhep-ph4 citations
14. 14*

    Mesonic String of Diquark-Quark Configuration at Finite Temperature

    A. Bakry🇨🇳 · X. Chen🇨🇳 · M. Deliyergiyev🇨🇳 · A. Galal🇨🇳 · S. Xu🇨🇳 · P.M. Zhang🇨🇳

    We investigate the distance and temperatures scale for which the string in baryonic quark configuration approaches the limiting behavior of mesonic strings in pure Yang-Mills SU(3) lattice gauge theory. We calculate and compare the numerical values of the Polyakov loop correlators and the width profile of both diquark-quark $(QQ)Q$ and mesonic $Q\bar{Q}$ strings. We find the diquark-quark configuration to exhibit an identical behavior to the mesonic string for the potential and energy-density width profile for temperature near the end of QCD plateau. In the vicinity of the deconfinement point; however, the symmetry in the energy-width profile with the meson does not manifest at both short and intermediate distance scales. Moreover, we observe significantly different numerical values for Polyakov loop correlators corresponding to each system. The splitting of the two identical system suggest that, in the high temperature region of the confined phase of QCD, the subsisted baryonic decouplet states overlap with the excited mesonic spectrum yielding the diquark-quark symmetry with the meson inexact in a small enough neighborhood of the critical point $T_c$.

    ↳ hep-lathep-phPoS(2018)·2 citations
15. 15*

    Search for sterile neutrinos in a universe of vacuum energy interacting with cold dark matter

    Lu Feng🇨🇳 · Jing-Fei Zhang🇨🇳 · Xin Zhang🇨🇳

    We investigate the cosmological constraints on sterile neutrinos in a universe in which vacuum energy interacts with cold dark matter by using latest observational data. We focus on two specific interaction models, $Q=\beta H{\rho }_{\mathrm{v}}$ and $Q=\beta H{\rho }_{\mathrm{c}}$. To overcome the problem of large-scale instability in the interacting dark energy scenario, we employ the parametrized post-Friedmann (PPF) approach for interacting dark energy to do the calculation of perturbation evolution. The observational data sets used in this work include the Planck 2015 temperature and polarization data, the baryon acoustic oscillation measurements, the type-Ia supernova data, the Hubble constant direct measurement, the galaxy weak lensing data, the redshift space distortion data, and the Planck lensing data. Using the all-data combination, we obtain $N_{\mathrm{eff}}<3.522$ and $m_{\nu ,\mathrm{sterile}}^{\mathrm{eff}}<0.576$ eV for the $Q=\beta H{\rho }_{\mathrm{v}}$ model, and $N_{\mathrm{eff}}=3.204_{-0.135}^{+0.049}$ and $m_{\nu ,\mathrm{sterile}}^{\mathrm{eff}}=0.410_{-0.330}^{+0.150}$ eV for the $Q=\beta H{\rho }_{\mathrm{c}}$ model. The latter indicates $\Delta N_{\mathrm{eff}}>0$ at the 1.17$\sigma$ level and a nonzero mass of sterile neutrino at the 1.24$\sigma$ level. In addition, for the $Q=\beta H{\rho }_{\mathrm{v}}$ model, we find that $\beta =0$ is consistent with the current data, and for the $Q=\beta H{\rho }_{\mathrm{c}}$ model, we find that $\beta >0$ is obtained at more than 1$\sigma$ level.

    ↳ astro-ph.COgr-qchep-phPhys.Dark Univ.(2019)·67 citations
16. 16*

    Fresh Insights on Cosmic-ray Propagation from the New AMS Data

    Nicola Tomassetti🇮🇹 · Jie Feng🇨🇳 · Alberto Oliva🇪🇸

    The Alpha Magnetic Spectrometer (AMS) experiment has released new measurements of primary and secondary nuclei in cosmic rays at the TeV energy scale. Using these data, we present new results based on a global Bayesian analysis of our two halo model of CR transport.

    ↳ astro-ph.HEhep-phRes.Notes AAS(2017)·2 citations
17. 17*

    Production of cosmic-ray antinuclei in the Galaxy and background for dark matter searches

    Nicola Tomassetti🇮🇹 · Alberto Oliva🇪🇸

    Antimatter nuclei in cosmic rays (CR) represent a promising discovery channel for the indirect search of dark matter. We present astrophysical background calculations of CR antideuteron ($\overline{d}$) and antihelium ($\overline{He}$). These particles are produced by high-energy collisions of CR protons and nuclei with the gas nuclei of the interstellar medium. In our calculations, we also consider production and shock acceleration of antinuclei in the shells of supernova remnants (SNRs). The total flux of $\overline{d}$ and $\overline{He}$ particles is constrained using new AMS measurements on the boron/carbon (B/C) and antiproton/proton ($\bar{p}/p$) ratios. The two ratios leads to different antiparticle fluxes in the high-energy regime $E\gtrsim$ 10 GeV/n where, in particular, $\bar{p}/p$-driven calculations leads to a significantly larger antiparticle flux in comparison to predictions from conventional B/C-driven constraints. On the other hand, both approaches provide consistent results in the sub-GeV/n energy window, which is where dark matter induced signal may exceed the astrophysical background. In this region, the total antinuclei flux, from interaction in the insterstellar gas and inside SNRs, is tightly bounded by the data. Shock-acceleration of antiparticles in SNRs has a minor influence in the astrophysical background for dark matter searches.

    ↳ astro-ph.HEhep-phPoS(2017)·5 citations
18. 18*

    $J$-factors for self-interacting dark matter in 20 dwarf spheroidal galaxies

    Sebastian Bergström🇸🇪 · Riccardo Catena🇸🇪 · Andrea Chiappo🇸🇪 · Jan Conrad🇸🇪 · Björn Eurenius🇸🇪 · Magdalena Eriksson🇸🇪 · Michael Högberg🇸🇪 · Susanna Larsson🇸🇪 · Emelie Olsson🇸🇪 · Andreas Unger🇸🇪 · Rikard Wadman🇸🇪

    Dwarf spheroidal galaxies are among the most promising targets for indirect dark matter (DM) searches in $\gamma$-rays. The $\gamma$-ray flux from DM annihilation in a dwarf spheroidal galaxy is proportional to the $J$-factor of the source. The $J$-factor of a dwarf spheroidal galaxy is the line-of-sight integral of the DM mass density squared times $⟨{\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}⟩/({\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}{)}_0$, where ${\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}$ is the DM annihilation cross-section times relative velocity $v_{\mathrm{rel}}=|{\mathbf{v}}_{\mathrm{rel}}|$, angle brackets denote average over ${\mathbf{v}}_{\mathrm{rel}}$, and $({\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}{)}_0$ is the $v_{\mathrm{rel}}$-independent part of ${\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}$. If ${\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}$ is constant in $v_{\mathrm{rel}}$, $J$-factors only depend on the DM space distribution in the source. However, if ${\sigma }_{\mathrm{ann}}{v}_{\mathrm{rel}}$ varies with $v_{\mathrm{rel}}$, as in the presence of DM self-interactions, $J$-factors also depend on the DM velocity distribution, and on the strength and range of the DM self-interaction. Models for self-interacting DM are increasingly important in the study of the small scale clustering of DM, and are compatible with current cosmological observations. Here we derive the $J$-factor of 20 dwarf spheroidal galaxies from stellar kinematic data under the assumption of Yukawa DM self-interactions. $J$-factors are derived through a profile Likelihood approach, assuming either NFW or cored DM profiles. We also compare our results with $J$-factors derived assuming the same velocity for all DM particles in the target galaxy. We find that this common approximation overestimates the $J$-factors by up to one order of magnitude. $J$-factors for a sample of DM particle masses, self-interaction coupling constants and density profiles are provided electronically, ready to be used in other projects.

    ↳ astro-ph.COhep-phPRD(2018)·24 citations
19. 19*

    A Strong Test of the Dark Matter Origin of the 1.4 TeV DAMPE Signal Using IceCube Neutrinos

    Yue Zhao🇺🇸 · Ke Fang🇺🇸 · Meng Su🇨🇳 · M. Coleman Miller🇺🇸

    A tentative excess in the electron spectrum at 1.4 TeV was recently reported by the DArk Matter Particle Explorer (DAMPE). A non-astrophysical scenario in which dark matter particles annihilate or decay in a local clump has been invoked to explain the excess. If $e^{\pm }$ annihilation channels in the final states are mediated by left-handed leptons as a component in the $SU(2{)}_L$ doublet, neutrinos with similar energies should have been simultaneously produced. We demonstrate that generic dark matter models can be decisively tested by the existing IceCube data. In case of a non-detection, such models would be excluded at the $5\sigma$ level by the five-year data for a point-like source and by the ten-year data for an extended source of dark matter particles with left-handed leptons.

    ↳ astro-ph.HEastro-ph.COhep-phJCAP(2018)·21 citations
20. 20*

    Nuclear modification of scalar, axial and tensor charges from lattice QCD

    Emmanuel Chang🇺🇸 · Zohreh Davoudi🇺🇸 · William Detmold🇺🇸 · Arjun S. Gambhir🇺🇸 · Kostas Orginos🇺🇸 · Martin J. Savage🇺🇸 · Phiala E. Shanahan🇺🇸 · Michael L. Wagman🇺🇸 · Frank Winter🇺🇸

    Complete flavour decompositions of the scalar, axial and tensor charges of the proton, deuteron, diproton and ${}^3$He at SU(3)-symmetric values of the quark masses corresponding to a pion mass $m_{\pi }\sim 806$ MeV are determined using lattice QCD. At the physical quark masses, the scalar charges constrain mean-field models of nuclei and the low-energy interactions of nuclei with potential dark matter candidates. The axial and tensor charges of nuclei constrain their spin content, integrated transversity and the quark contributions to their electric dipole moments. External fields are used to directly access the quark-line connected matrix elements of quark bilinear operators, and a combination of stochastic estimation techniques is used to determine the disconnected sea-quark contributions. Significant nuclear modifications are found, with particularly large, O(10%), effects in the scalar charges. Typically, these nuclear effects reduce the effective charge of the nucleon (quenching), although in some cases an enhancement is not excluded. Given the size of the nuclear modifications of the scalar charges resolved here, contributions from correlated multi-nucleon effects should be quantified in the analysis of dark matter direct-detection experiments using nuclear targets.

    ↳ hep-lathep-phnucl-thPRL(2018)·67 citations
21. 21*

    What can we learn from the stochastic gravitational wave background produced by oscillons?

    Stefan Antusch🇨🇭 · Francesco Cefala🇨🇭 · Stefano Orani🇨🇭

    The stochastic gravitational wave (GW) background provides a fascinating window to the physics of the very early universe. Beyond the nearly scale-invariant primordial GW spectrum produced during inflation, a spectrum with a much richer structure is typically generated during the preheating phase after inflation (or after some other phase transition at lower energies). This raises the question of what one can learn from a future observation of the stochastic gravitational wave background spectrum about the underlying physics during preheating. Recently, it has been shown that during preheating non-perturbative quasi-stable objects like oscillons can act as strong sources for GW, leading to characteristic features such as distinct peaks in the spectrum. In this paper, we study the GW production from oscillons using semi-analytical techniques. In particular, we discuss how the GW spectrum is affected by the parameters that characterise a given oscillon system, e.g. by the background cosmology, the asymmetry of the oscillons and the evolution of the number density of the oscillons. We compare our semi-analytic results with numerical lattice simulations for a hilltop inflation model and a KKLT scenario, which differ strongly in some of these characteristics, and find very good agreement.

    ↳ astro-ph.COgr-qchep-phJCAP(2018)·60 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.