Tue·Sep 13, 2016Tuesday·September 13, 2016

1. 01*

   Second order differential equations for bosons with spin j > 1 and in the bases of general tensor-spinors of rank-2j

   V. M. Banda Guzman🇲🇽 · M. Kirchbach🇲🇽

   A boson of spin-j>1 can be described in one of the possibilities within the Bargmann-Wigner framework by means of one sole differential equation of order twice the spin, which however is known to be inconsistent as it allows for non-local, ghost and acausally propagating solutions, all problems which are difficult to tackle. The other possibility is provided by the Fierz-Pauli framework which is based on the more comfortable to deal with second order Klein-Gordon equation, but it needs to be supplemented by an auxiliary condition. Although the latter formalism avoids some of the pathologies of the high-order equations, it still remains plagued by some inconsistencies such as the acausal propagation of the wave fronts of the (classical) solutions within an electromagnetic environment. We here suggest a method alternative to the above two that combines their advantages while avoiding the related difficulties. Namely, we suggest one sole strictly (j,0)+ (0,j) representation specific second order differential equation, which is derivable from a Lagrangian and whose solutions do not violate causality. The equation under discussion presents itself as the product of the Klein-Gordon operator with a momentum independent projector on Lorentz irreducible representation spaces constructed from one of the Casimir invariants of the spin-Lorentz group. The basis used is that of general tensor-spinors of rank-2j.

   hep-phEur.Phys.J.Plus(2016)·2 citations
2. 02*

   Low scale left-right-right-left symmetry

   Gauhar Abbas🇪🇸

   We propose an effective left-right-right-left model with a parity breaking scale around a few TeV. One of the main achievements of the model is that the mirror fermions as well as the mirror gauge sector simultaneously could be at TeV scale. It is shown that the most dangerous quadratic divergence of the SM Higgs boson involving the top quark in the loop is naturally suppressed, and begins at three loop. The model postpones the fine-tuning of the mass of the SM Higgs boson up to a sufficiently high scale. The model explains the smallness of the neutrino masses whether they are Dirac or Majorana. Furthermore, the strong $CP$ phase is zero in this model.

   hep-phPRD(2017)·15 citations
3. 03*

   Hydrodynamic Predictions for Pb+Pb Collisions at 5.02 A TeV

   Scott McDonald🇨🇦 · Chun Shen🇨🇦 · Francois Fillion-Gourdeau🇨🇦 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

   Predictions and comparisons of hadronic flow observables for Pb+Pb collisions at 2.76 A TeV and 5.02 A TeV are presented using a hydrodynamics + hadronic cascade hybrid approach. Initial conditions are generated via a new formulation of the IP-Glasma model and then evolved using relativistic viscous hydrodynamics and finally fed into transport cascade in the hadronic phase. The results of this work show excellent agreement with the recent charged hadron anisotropic flow measurements from the ALICE collaboration of Pb+Pb collisions at 5.02 A TeV. Event-by-event distributions of charged hadron v n , flow event-plane correlations, and flow factorization breaking ratios are compared with existing measurements at 2.76 A TeV, and are predicted at 5.02 A TeV. Further predictions of identified hadron observables (for both light and multi-strange hadrons), such as p T -spectra and anisotropic flow coefficients, are presented.

   hep-phnucl-exnucl-thPRC(2017)·143 citations
4. 04*

   Creation and evolution of particle numberasymmetry in an expanding universe

   Takuya Morozumi🇯🇵 · Keiko I. Nagao🇯🇵 · Apriadi Salim Adam🇯🇵 · Hiroyuki Takata🇷🇺

   We introduce a model which may generate particle number asymmetry in an expanding Universe. The model includes CP violating and particle number violating interactions. The model consists of a real scalar field and a complex scalar field. Starting with an initial condition specified by a density matrix, we show how the asymmetry is created through the interaction and how it evolves at later time. We compute the asymmetry using non-equilibrium quantum field theory and as a first test of the model, we study how the asymmetry evolves in the flat limit.

   hep-phRuss.Phys.J.(2017)·2 citations
5. 05*

   Physics at a Higgs Factory

   Matthew Reece🇺🇸

   I give an overview of the physics potential at possible future $e^{+}{e}^{-}$ colliders, including the ILC, FCC-ee, and CEPC. The goal is to explain some of the measurements that can be done in the context of electroweak precision tests and Higgs couplings, to compare some of the options under consideration, and to put the measurements in context by summarizing their implications for some new physics scenarios. This is a writeup of a plenary talk at the Hong Kong University of Science and Technology Jockey Club Institute for Advanced Study Program on High Energy Physics Conference, January 18--21, 2016. Some previously unpublished electroweak precision results for FCC-ee and CEPC are included.

   hep-phInt.J.Mod.Phys.A(2016)·5 citations
6. 06*

   Excited State Mass spectra of doubly heavy baryons ${\Omega }_{cc}$, ${\Omega }_{bb}$ and ${\Omega }_{bc}$

   Zalak Shah🇮🇳 · Kaushal Thakkar🇮🇳 · Ajay Kumar Rai🇮🇳

   We discuss the mass spectrum of $\Omega$ baryon with two heavy quarks and one light quark (\textit{ccs, bbs and bcs}). The main goal of the paper is to calculate the ground state masses and after that, the positive and negative parity excited states masses are also obtained within a Hypercentral Constituent quark model, using coulomb plus linear potential framework. We also added first order correction to the potential. The mass spectra upto 5S for radial excited states and 1P-5P, 1D-4D and 1F-2F states for orbital excited states are computed for ${\Omega }_{cc}$, ${\Omega }_{bb}$ and ${\Omega }_{bc}$ baryons. Our obtained results are compared with other theoretical predictions which could be a useful complementary tool for the interpretation of experimentaly unknown heavy baryon spectra. The Regge trajectory is constructed in both ($n_r$, $M^2$) and ($J$, $M^2$) planes for ${\Omega }_{cc}$,${\Omega }_{bb}$ and ${\Omega }_{bc}$ baryons and their slopes and intercepts are also determined. Magnetic moments of doubly heavy ${\Omega }^{\prime }$s are also calculated.

   hep-phnucl-thEPJC(2016)·110 citations
7. 07*

   Multiphoton amplitudes and generalized LKF transformation in scalar QED using the worldline formalism

   Naser Ahmadiniaz🇰🇷 · Adnan Bashir🇲🇽 · Christian Schubert🇲🇽

   We apply the worldline formalism to scalar quantum electrodynamics (QED) to find a Bern-Kosower type master formula for generalized Compton scattering, on-shell and off-shell. Moreover, we use it to study the non-perturbative gauge parameter dependence of amplitudes in scalar QED and, as our main result, find a simple non-perturbative transformation rule under changes of this parameter in x-space in terms of conformal cross ratios. This generalizes the well-known Landau-Khalatnikov-Fradkin transformation (LKFT). We also exemplify how the LKFT works in perturbation theory.

   hep-phRuss.Phys.J.(2017)·5 citations
8. 08*

   Numerical magneto-hydrodynamics for relativistic nuclear collisions

   Gabriele Inghirami🇩🇪 · Luca Del Zanna🇮🇹 · Andrea Beraudo🇮🇹 · Mohsen Haddadi Moghaddam🇮🇷 · Francesco Becattini🇮🇹 · Marcus Bleicher🇩🇪

   We present an improved version of the ECHO-QGP numerical code, which self-consistently includes for the first time the effects of electromagnetic fields within the framework of relativistic magnetohydrodynamics (RMHD). We discuss results of its application in relativistic heavy-ion collisions in the limit of infinite electrical conductivity of the plasma. After reviewing the relevant covariant $3+1$ formalisms, we illustrate the implementation of the evolution equations in the code and show the results of several tests aimed at assessing the accuracy and robustness of the implementation. After providing some estimates of the magnetic fields arising in non-central high-energy nuclear collisions, we perform full RMHD simulations of the evolution of the Quark-Gluon Plasma in the presence of electromagnetic fields and discuss the results. In our ideal RMHD setup we find that the magnetic field developing in non-central collisions does not significantly modify the elliptic-flow of the final hadrons. However, since there are uncertainties in the description of the pre-equilibrium phase and also in the properties of the medium, a more extensive survey of the possible initial conditions as well as the inclusion of dissipative effects are indeed necessary to validate this preliminary result.

   hep-phnucl-thEPJC(2016)·179 citations
9. 09*

   Hadron spectroscopy and interactions from lattice QCD

   Sasa Prelovsek🇸🇮

   Lattice QCD approach to study the hadronic resonances and exotic hadrons is described at an introductory level. The main challenge is that these states decay strongly via one or more decay channels, and they often lie near thersholds. Specific results for conventional and exotic hadrons are shown to illustrate the current status.

   hep-phhep-latEPJ Web Conf.(2016)·4 citations
10. 10*

    Strongly coupled non-Abelian plasmas in a magnetic field

    Renato Critelli🇧🇷

    In this dissertation we use the gauge/gravity duality approach to study the dynamics of strongly coupled non-Abelian plasmas. Ultimately, we want to understand the properties of the quark-gluon plasma (QGP), whose scientifc interest by the scientific community escalated exponentially after its discovery in the 2000's through the collision of ultrarelativistic heavy ions. One can enrich the dynamics of the QGP by adding an external field, such as the baryon chemical potential (needed to study the QCD phase diagram), or a magnetic field. In this dissertation, we choose to investigate the magnetic effects. Indeed, there are compelling evidences that strong magnetic fields of the order $eB\sim 10m_{\pi }^2$ are created in the early stages of ultrarelativistic heavy ion collisions. The chosen observable to scan possible effects of the magnetic field on the QGP was the viscosity, due to the famous result $\eta /s=1/4\pi$ obtained via holography. In a first approach we use a caricature of the QGP, the $\mathcal{N}=4$ super Yang-Mills plasma to calculate the deviations of the viscosity as we add a magnetic field. We must emphasize, though, that a magnetized plasma has a priori seven viscosity coefficients (five shears and two bulks). In addition, we also study in this same model the anisotropic heavy quark-antiquark potential in the presence of a magnetic field. In the end, we propose a phenomenological holographic QCD-like model, which is built upon the lattice QCD data, to study the thermodynamics and the viscosity of the QGP with an external strong magnetic field.

    hep-phhep-thnucl-th2 citations
11. 11*

    Neutrino potential for neutrinoless double beta decay

    Yoritaka Iwata🇯🇵

    Neutrino potential for neutrinoless double beta decay is studied with focusing on its statistical property. The statistics provide a gross view of understanding amplitude of constitutional components of the nuclear matrix element.

    hep-phnucl-thNucl.Phys.Rev.(2017)·2 citations
12. 12*

    Parity-doublet representation of Majorana fermions and neutron oscillation

    Kazuo Fujikawa🇯🇵 · Anca Tureanu🇫🇮

    We present a parity-doublet theorem for the representation of the intrinsic parity of Majorana fermions, which is expected to be useful also in condensed matter physics, and it is illustrated to provide a criterion of neutron-antineutron oscillation in a BCS-like effective theory with $\Delta B=2$ baryon number violating terms. The CP violation in the present effective theory causes no direct CP violating effects in the oscillation itself, which is demonstrated by the exact solution, although it influences the neutron electric dipole moment in the leading order of small $\Delta B=2$ parameters. An analogue of Bogoliubov transformation, which preserves P and CP, is crucial in the analysis.

    hep-phcond-mat.str-elcond-mat.supr-conhep-thPRD(2016)·18 citations
13. 13*

    Possible strange hidden-charm pentaquarks from ${\Sigma }_c^{(\ast )}{\bar{D}}_s^{\ast }$ and ${\Xi }_c^{{(}^{\prime },\ast )}{\bar{D}}^{\ast }$ interactions

    Rui Chen🇨🇳 · Jun He🇨🇳 · Xiang Liu🇨🇳

    Using the one-boson-exchange model, we investigate the ${\Lambda }_c{\bar{D}}_s^{\ast }$, ${\Sigma }_c{\bar{D}}_s^{\ast }$, ${\Sigma }_c^{\ast }{\bar{D}}_s^{\ast }$, ${\Xi }_c{\bar{D}}^{\ast }$, ${\Xi }_c^{\prime }{\bar{D}}^{\ast }$, and ${\Xi }_c^{\ast }{\bar{D}}^{\ast }$ interactions by considering the one-eta-exchange and/or one-pion-exchange contributions. We further predict the existence of hidden-charm molecular pentaquarks. Promising candidates for hidden-charm molecular pentaquarks include a ${\Xi }_c^{\prime }{\bar{D}}^{\ast }$ state with $0({\frac{1}{2}}^{-})$ and the ${\Xi }_c^{\ast }{\bar{D}}^{\ast }$ states with $0({\frac{1}{2}}^{-})$ and $0({\frac{3}{2}}^{-})$. Experimental searches for these predicted hidden-charm molecular pentaquarks are an interesting future research topic for experiments like LHCb.

    hep-phhep-exhep-latnucl-ex+1CPC(2017)·95 citations
14. 14*

    Neutrino Masses and Scalar Singlet Dark Matter

    Subhaditya Bhattacharya🇮🇳 · Sudip Jana🇺🇸 · S. Nandi🇺🇸

    We propose a simple extension of the Standard Model (SM) which has a viable dark matter (DM) candidate, as well as can explain the generation of tiny neutrino masses. The DM is an electroweak (EW) singlet scalar $S$, odd under an imposed exact $Z_2$ symmetry, interacting to SM through `Higgs-portal' coupling, while all other particles are even under $Z_2$. The model also has an EW isospin $3/2$ scalar, $\Delta$ and a pair of EW isospin vector, $\Sigma$ and $\bar{\Sigma }$, responsible for generating tiny neutrino mass via the effective dimension seven operator. Thanks to the additional interactions with $\Delta$, the scalar singlet DM $S$ survives a large region of parameter space by relic density constraints from WMAP/PLANCK and direct search bounds from updated LUX data. Constraints on the model from Large Hadron Collider (LHC) has also been discussed.

    hep-phPRD(2017)·51 citations
15. 15*

    Naturalness in see-saw mechanism and Bogoliubov transformation

    Kazuo Fujikawa🇯🇵 · Anca Tureanu🇫🇮

    We present an alternative perspective on the see-saw mechanism for the neutrino mass, according to which the small neutrino mass is given as a difference of two large masses. This view emerges when an analogue of the Bogoliubov transformation is used to describe Majorana neutrinos in the Lagrangian of the see-saw mechanism, which is analogous to the BCS theory. The Bogoliubov transformation clarifies the natural appearance of Majorana fermions when C is strongly violated by the right-handed neutrino mass term with good CP in the single flavor model. Analyzing typical models with $m_R$= $10^4$ to $10^{15}$ GeV, it is shown that a hitherto unrecognized fine tuning of the order $m_{\nu }/m_R=10^{-15}$ to $10^{-26}$ is required to make the commonly perceived see-saw mechanism work in a natural setting, namely, when none of dimensionless coupling constants are very small.

    hep-phcond-mat.str-elcond-mat.supr-conhep-thPLB(2017)·12 citations
16. 16*

    The new ABMP16 PDF

    S. Alekhin🇩🇪 · J. Bluemlein🇩🇪 · S. Moch🇩🇪 · R. Placakyte🇩🇪

    We present an update of the ABM12 PDF analysis including improved constraints due to the final version of the inclusive DIS HERA data, the Tevatron and LHC data on the W- and Z-production and those on heavy-quark production in the electron- and neutrino-induced DIS at HERA and the fixed-target experiments NOMAD and CHORUS. We also check the impact of the Tevatron and LHC top-quark production data on the PDFs and the strong coupling constant. We obtain ${\alpha }_s(M_Z)=0.1145(9)$ and $0.1147(8)$ with and without the top-quark data included, respectively.

    hep-phPoS(2016)·36 citations
17. 17*

    XYZ-like Spectra from Laplace Sum Rule at N2LO in the Chiral Limit

    R. Albuquerque (UERJ, Rio de Janeiro-BR)🇧🇷 · S. Narison (LUPM-CNRS, Montpellier-FR)🇫🇷 · F. Fanomezana🇲🇬 · A. Rabemananjara🇲🇬 · D. Rabetiarivony🇲🇬 · G. Randriamanatrika (iHEPMAD, Antananarivo-MG)🇲🇬

    We present new compact integrated expressions of QCD spectral functions of heavy-light molecules and four-quark $XYZ$-like states at lowest order (LO) of perturbative (PT) QCD and up to $d=8$ condensates of the Operator Product Expansion (OPE). Then, by including up to next-to-next leading order (N2LO) PT QCD corrections, which we have estimated by assuming the factorization of the four-quark spectral functions, we improve previous LO results from QCD spectral sum rules (QSSR), on the $XYZ$-like masses and decay constants which suffer from the ill-defined heavy quark mass. PT N3LO corrections are estimated using a geometric growth of the PT series and are included in the systematic errors. Our optimal results based on stability criteria are summarized in Tables 11 to 14 and compared, in Section 10, with experimental candidates and some LO QSSR results. We conclude that the masses of the $XZ$ observed states are compatible with (almost) pure $J^{PC}=1^{+\pm },0^{++}$ molecule or/and four-quark states. The ones of the $1^{-\pm },0^{-\pm }$ molecule / four-quark states are about 1.5 GeV above the $Y_{c,b}$ mesons experimental candidates and hadronic thresholds. We also find that the couplings of these exotics to the associated interpolating currents are weaker than that of ordinary $D,B$ mesons ($f_{DD}\approx 10^{-3}{f}_D$) and may behave numerically as $1/{\bar{m}}_b^{3/2}$ (resp. $1/{\bar{m}}_b$) for the $1^{+},0^{+}$ (resp. $1^{-},0^{-}$) states which can stimulate further theoretical studies of these decay constants.

    hep-phhep-exhep-latInt.J.Mod.Phys.A(2016)·40 citations
18. 18*

    Fermionic Dark Matter in a simple $t$-channel model

    Ashok Goyal🇿🇦 · Mukesh Kumar🇿🇦

    We consider a fermionic dark matter (DM) particle in renormalizable Standard Model (SM) gauge interactions in a simple $t$-channel model. The DM particle interactions with SM fermions is through the exchange of scalar and vector mediators which carry colour or lepton number. In the case of coloured mediators considered in this study, we find that if the DM is thermally produced and accounts for the observed relic density almost the entire parameter space is ruled out by the direct detection observations. The bounds from the monojet plus missing energy searches at the Large Hadron Collider are less stringent in this case. In contrast for the case of Majorana DM, we obtain strong bounds from the monojet searches which rule out DM particles of mass less than about a few hundred GeV for both the scalar and vector mediators.

    hep-phJCAP(2016)·6 citations
19. 19*

    NLO QCD Predictions for off-shell $t\bar{t}$ and $t\bar{t}H$ Production and Decay at a Linear Collider

    Bijan Chokoufé Nejad🇩🇪 · Wolfgang Kilian🇩🇪 · Jonas M. Lindert🇨🇭 · Stefano Pozzorini🇨🇭 · Jürgen Reuter🇩🇪 · Christian Weiss🇩🇪

    We present predictions for $t\bar{t}$ and $t\bar{t}H$ production and decay at future lepton colliders including non-resonant and interference contributions up to next-to-leading order (NLO) in perturbative QCD. The obtained precision predictions are necessary for a future precise determination of the top-quark Yukawa coupling, and allow for top-quark phenomenology in the continuum at an unprecedented level of accuracy. Simulations are performed with the automated NLO Monte-Carlo framework WHIZARD interfaced to the OpenLoops matrix element generator.

    hep-phhep-exJHEP(2016)·67 citations
20. 20*

    New Results on Massive 3-Loop Wilson Coefficients in Deep-Inelastic Scattering

    J. Ablinger🇦🇹 · A. Behring🇩🇪 · J. Blümlein🇩🇪 · G. Falcioni🇩🇪 · A. De Freitas🇩🇪 · A. Hasselhuhn🇩🇪 · A. von Manteuffel🇩🇪 · M. Round🇦🇹 · C. Schneider🇦🇹 · F. Wißbrock🇫🇷

    We present recent results on newly calculated 2- and 3-loop contributions to the heavy quark parts of the structure functions in deep-inelastic scattering due to charm and bottom.

    hep-phhep-exhep-thPoS(2016)·6 citations
21. 21*

    Type-II Leptogenesis

    Jihn E. Kim🇰🇷

    I will talk on our new theory on baryogenesis through type-II leptogenesis which is different from the well-known type-I leptogenesis. I will comment on the Jarlskog phases, ${\delta }_{\mathrm{CKM}}$ and ${\delta }_{\mathrm{PMNS}}$, in the CKM and PMNS matrices. In the type-II leptogenesis, the PMNS phase is used for Sakharov's condition on the global quantum number generation in the Universe. For this to be effective, the SU(2)$\times$U(1) gauge symmetry must be broken during the leptogenesis epoch.

    hep-phastro-ph.COPoS(2016)·1 citation
22. 22*

    Deuteron structure in the deep inelastic regime

    C.A. Garcìa Canal🇦🇷 · T. Tarutina🇦🇷 · V. Vento🇪🇸

    We study nuclear effects on the deuteron in the deep inelastic regime using the newest available data analyzing their $Q^2$ dependence. We conclude that precise EMC ratios for large $Q^2$ (> 30, GeV${}^2$) cannot be obtained without considering these nuclear effects. For this purpose we use a scheme which parametrizes these effects in a simple manner and compare our results with other recent proposals.

    hep-phnucl-thEPJA(2017)·4 citations
23. 23*

    Phenomenology of the SU(3)_C \otimes SU(2)_L \otimes SU(3)_R \otimes U(1)_X gauge model

    P. V. Dong🇻🇳 · D. T. Huong🇻🇳 · D. V. Loi🇻🇳 · N. T. Nhuan🇻🇳 · N. T. K. Ngan🇻🇳

    We study the left-right asymmetric model based on SU(3)_C \otimes SU(2)_L \otimes SU(3)_R \otimes U(1)_X gauge group, which improves the theoretical and phenomenological aspects of the known left-right symmetric model. This new gauge symmetry yields that the fermion generation number is three, and the tree-level flavor-changing neutral currents arise in both gauge and scalar sectors. Also, it can provide the observed neutrino masses as well as dark matter automatically. Further, we investigate the mass spectrum of the gauge and scalar fields. All the gauge interactions of the fermions and scalars are derived. We examine the tree-level contributions of the new neutral vector, Z'_R, and new neutral scalar, H_2, to flavor-violating neutral meson mixings, say K-\bar{K}, B_d-\bar{B}_d, and B_s-\bar{B}_s, which strongly constrain the new physics scale as well as the elements of the right-handed quark mixing matrices. The bounds for the new physics scale are in agreement with those coming from the \rho-parameter as well as the mixing parameters between W, Z bosons and new gauge bosons.

    hep-phPRD(2017)·11 citations
24. 24*

    R-Matrix Calculations for Few-Quark Bound States

    M. A. Shalchi🇧🇷 · M. R. Hadizadeh🇺🇸

    The R--matrix method is implemented to study the heavy charm and bottom diquark, triquark, tetraquark and pentaquarks in configuration space, as the bound states of quark--antiquark, diquark--quark, diquark--antidiquark and diquark--antitriquark systems, respectively. The mass spectrum and the size of these systems are calculated for different partial wave channels. The calculated masses are compared with recent theoretical results obtained by other methods in momentum and configuration spaces and also by available experimental data.

    hep-phnucl-thEPJC(2016)·1 citation
25. 25*

    Non-standard interactions with high-energy atmospheric neutrinos at IceCube

    Jordi Salvado🇪🇸 · Olga Mena🇪🇸 · Sergio Palomares-Ruiz🇪🇸 · Nuria Rius🇪🇸

    Non-standard interactions in the propagation of neutrinos in matter can lead to significant deviations from expectations within the standard neutrino oscillation framework and atmospheric neutrino detectors have been considered to set constraints. However, most previous works have focused on relatively low-energy atmospheric neutrino data. Here, we consider the one-year high-energy through-going muon data in IceCube, which has been already used to search for light sterile neutrinos, to constrain new interactions in the $\mu \tau$-sector. In our analysis we include several systematic uncertainties on both, the atmospheric neutrino flux and on the detector properties, which are accounted for via nuisance parameters. After considering different primary cosmic-ray spectra and hadronic interaction models, we obtain the most stringent bound on the off-diagonal ${\epsilon }_{\mu \tau }$ parameter to date, with the 90\% credible interval given by $-6.0\times 10^{-3}<{\epsilon }_{\mu \tau }<5.4\times 10^{-3}$. In addition, we also estimate the expected sensitivity after 10~years of collected data in IceCube and study the precision at which non-standard parameters could be determined for the case of ${\epsilon }_{\mu \tau }$ near its current bound.

    hep-phJHEP(2017)·68 citations
26. 26*

    Recent Results on Radiative and Electroweak Penguin B Decays at Belle

    Akimasa Ishikawa🇯🇵

    We report on recent results on radiative and electroweak penguin B decays at Belle at KEKB accelerator.

    ↳ hep-exhep-phPoS(2017)·0 citations
27. 27*

    Prospects for Detecting Galactic Sources of Cosmic Neutrinos with IceCube: An Update

    Francis Halzen🇺🇸 · Ali Kheirandish🇺🇸 · Viviana Niro🇪🇸

    Air-Cherenkov telescopes have mapped the Galactic plane at TeV energies. Here we evaluate the prospects for detecting the neutrino emission from sources in the Galactic plane assuming that the highest energy photons originate from the decay of pions, which yields a straightforward prediction for the neutrino flux from the decay of the associated production of charged pions. Four promising sources are identified based on having a large flux and a flat spectrum. We subsequently evaluate the probability of their identification above the atmospheric neutrino background in IceCube data as a function of time. We show that observing them over the twenty-year lifetime of the instrumentation is likely, and that some should be observable at the $3\sigma$ level with six years of data. In the absence of positive results, we derive constraints on the spectral index and cut-off energy of the sources, assuming a hadronic acceleration mechanism.

    ↳ astro-ph.HEhep-phAstropart.Phys.(2017)·40 citations
28. 28*

    Flavor versus mass eigenstates in neutrino asymmetries: implications for cosmology

    Gabriela Barenboim🇪🇸 · William H. Kinney🇺🇸 · Wan-Il Park🇪🇸

    We show that, if they exist, lepton number asymmetries ($L_{\alpha }$) of neutrino flavors should be distinguished from the ones ($L_i$) of mass eigenstates, since Big Bang Nucleosynthesis (BBN) bounds on the flavor eigenstates cannot be directly applied to the mass eigenstates. Similarly, Cosmic Microwave Background (CMB) constraints on mass eigenstates do not directly constrain flavor asymmetries. Due to the difference of mass and flavor eigenstates, the cosmological constraint on the asymmetries of neutrino flavors can be much stronger than conventional expectation, but not uniquely determined unless at least the asymmetry of the heaviest neutrino is well constrained. Cosmological constraint on $L_i$ for a specific case is presented as an illustration.

    ↳ astro-ph.COhep-phEPJC(2017)·58 citations
29. 29*

    Beta spectrum of unique first-forbidden decays as a novel test for fundamental symmetries

    Ayala Glick-Magid (HUJI)🇮🇱 · Yonatan Mishnayot (HUJI, WIS, SNRC)🇮🇱 · Ish Mukul (WIS)🇮🇱 · Michael Hass (WIS)🇮🇱 · Guy Ron (HUJI)🇮🇱 · Sergey Vaintraub (SNRC)🇮🇱 · Doron Gazit (HUJI)🇮🇱

    Within the Standard Model, the weak interaction of quarks and leptons is characterized by certain symmetry properties, such as maximal breaking of parity and favored helicity. These are related to the $V-A$ structure of the weak interaction. These characteristics were discovered by studying correlations in the directions of the outgoing leptons in nuclear beta decays. These days, correlation measurements in nuclear beta decays are intensively studied to probe for signatures for deviations from these symmetries, which are an indication of Beyond Standard Model physics. We show that the structure of the energy spectrum of emitted electrons in unique first-forbidden $\beta$-decays is sensitive to the symmetries of the weak interaction, and thus can be used as a novel probe of physics beyond the standard model. Furthermore, the energy spectrum gives constraints both in the case of right and left coupling of the new symmetry currents. We show that a measurement with modest energy resolution of about 20 keV is expected to lead to new constraints on beyond the standard model interactions with tensor symmetry.

    ↳ nucl-exhep-phnucl-thPLB(2017)·27 citations
30. 30*

    Neutral Kaon Mixing Beyond the Standard Model with $n_f=2+1$ Chiral Fermions Part 1: Bare Matrix Elements and Physical Results

    Nicolas Garron🇬🇧 · Renwick J. Hudspith🇨🇦 · Andrew T. Lytle🇬🇧

    We compute the hadronic matrix elements of the four-quark operators relevant for $K^0-{\bar{K}}^0$ mixing beyond the Standard Model. Our results are from lattice QCD simulations with $n_f=2+1$ flavours of domain-wall fermion, which exhibit continuum-like chiral-flavour symmetry. The simulations are performed at two different values of the lattice spacing ($a\sim 0.08$ and $a\sim 0.11\text{fm}$) and with lightest unitary pion mass $\sim 300\text{MeV}$. For the first time, the full set of relevant four-quark operators is renormalised non-perturbatively through RI-SMOM schemes; a detailed description of the renormalisation procedure is presented in a companion paper. We argue that the intermediate renormalisation scheme is responsible for the discrepancies found by different collaborations. We also study different normalisations and determine the matrix elements of the relevant four-quark operators with a precision of $\sim 5\%$ or better.

    ↳ hep-lathep-phJHEP(2016)·70 citations
31. 31*

    Elastic scattering, polarization and absorption of relativistic antiprotons on nuclei

    A.B. Larionov🇩🇪 · H. Lenske🇩🇪

    We perform Glauber model calculations of the antiproton-nucleus elastic and quasielastic scattering and absorption in the beam momentum range $\sim 0.5÷10$ GeV/c. A good agreement of our calculations with available LEAR data and with earlier Glauber model studies of the $\bar{p}A$ elastic scattering allows us to make predictions at the beam momenta of $\sim 10$ GeV/c, i.e. at the regime of the PANDA experiment at FAIR. The comparison with the proton-nucleus elastic scattering cross sections shows that the diffractive minima are much deeper in the $\bar{p}A$ case due to smaller absolute value of the ratio of the real-to-imaginary part of the elementary elastic amplitude. Significant polarization signal for $\bar{p}A$ elastic scattering at 10 GeV/c is expected. We have also revealed a strong dependence of the $\bar{p}A$ absorption cross section on the slope parameter of the transverse momentum dependence of the elementary $\bar{p}N$ amplitude. The $\bar{p}A$ optical potential is discussed.

    ↳ nucl-thhep-exhep-phnucl-exNPA(2017)·12 citations
32. 32*

    New CMB constraints for Abelian Higgs cosmic strings

    Joanes Lizarraga🇪🇸 · Jon Urrestilla🇪🇸 · David Daverio🇨🇭 · Mark Hindmarsh🇬🇧 · Martin Kunz🇨🇭

    We present cosmic microwave background (CMB) power spectra from recent numerical simulations of cosmic strings in the Abelian Higgs model and compare them to CMB power spectra measured by Planck. We obtain revised constraints on the cosmic string tension parameter $G\mu$. For example, in the $\Lambda$CDM model with the addition of strings and no primordial tensor perturbations, we find $G\mu <2.0\times 10^{-7}$ at 95% confidence, about 20% lower than the value obtained from previous simulations, which had 1/64 of the spatial volume. We investigate the source of the difference, showing that the main cause is an improved treatment of the string evolution across the radiation-matter transition. The increased computational volume also makes possible to simulate fully the physical equations of motion, in which the string cores shrink in comoving coordinates. This, and the larger dynamic range, changes the amplitude of the power spectra by only about 10%, demonstrating that field theory simulations of cosmic strings have now reached the required dynamic range for CMB calculations.

    ↳ astro-ph.COhep-phhep-thJCAP(2016)·109 citations
33. 33*

    Determination of the ${\mathbf{\eta }}^3\mathrm{He}$ threshold structure from the low energy $\mathbf{pd}\to {\mathbf{\eta }}^3\mathrm{He}$ reaction

    Ju-Jun Xie🇨🇳 · Wei-Hong Liang🇨🇳 · Eulogio Oset🇪🇸 · Pawel Moskal🇵🇱 · Magdalena Skurzok🇵🇱 · Colin Wilkin🇬🇧

    We analyze the data on cross sections and asymmetries for the $pd(dp)\to {\eta }^3\mathrm{He}$ reaction close to threshold and look for bound states of the ${\eta }^3\mathrm{He}$ system. Rather than parameterizing the scattering matrix, as is usually done, we develop a framework in which the ${\eta }^3\mathrm{He}$ optical potential is the key ingredient, and its strength, together with some production parameters, are fitted to the available experimental data. The relationship of the scattering matrix to the optical potential is established using the Bethe-Salpeter equation and the ${\eta }^3\mathrm{He}$ loop function incorporates the range of the interaction given by the empirical ${}^3\mathrm{He}$ density. We find a local Breit Wigner form of the ${\eta }^3$He amplitude $T$ below threshold with a clear peak in $|T{|}^2$, which corresponds to an ${\eta }^3\mathrm{He}$ binding of about 0.3 MeV and a width of about 3 MeV. By fitting the potential we can also evaluate the ${\eta }^3\mathrm{He}$ scattering length, including its sign, thus resolving the ambiguity in the former analyses.

    ↳ nucl-thhep-phPRC(2017)·45 citations
34. 34*

    Breaking the sound barrier in AdS/CFT

    Carlos Hoyos🇪🇸 · Niko Jokela🇫🇮 · David Rodríguez Fernández🇪🇸 · Aleksi Vuorinen🇫🇮

    It has been conjectured that the speed of sound in holographic models with UV fixed points has an upper bound set by the value of the quantity in conformal field theory. If true, this would set stringent constraints for the presence of strongly coupled quark matter in the cores of physical neutron stars, as the existence of two-solar-mass stars appears to demand a very stiff Equation of State. In this article, we present a family of counterexamples to the speed of sound conjecture, consisting of strongly coupled theories at finite density. The theories we consider include $\mathcal{N}=4$ super Yang-Mills at finite R-charge density and non-zero gaugino masses, while the holographic duals are Einstein-Maxwell theories with a minimally coupled scalar in a charged black hole geometry. We show that for a small breaking of conformal invariance, the speed of sound approaches the conformal value from above at large chemical potentials.

    ↳ hep-thastro-ph.HEhep-phnucl-thPRD(2016)·75 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.