Fri·Sep 9, 2016Friday·September 9, 2016

1. 01*

   Gauge Mediation Models with Adjoint Messengers

   Ilia Gogoladze🇺🇸 · Azar Mustafayev🇺🇸 · Qaisar Shafi🇺🇸 · Cem Salih Un🇹🇷

   We present a class of models in the framework of gauge mediation supersymmetry breaking where the messenger fields transform in the adjoint representation of the Standard Model gauge symmetry. To avoid unacceptably light right-handed sleptons in the spectrum we introduce a non-zero U(1)_B-L D-term. This leads to an additional contribution to the soft supersymmetry breaking mass terms which makes the right-handed slepton masses compatible with the current experimental bounds. We show that in this framework the observed 125 GeV Higgs boson mass can be accommodated with the sleptons accessible at the LHC, while the squarks and gluinos lie in the multi-TeV range. We also discuss the issue of the fine-tuning and show that the desired relic dark matter abundance can also be accommodated.

   hep-phPRD(2016)·7 citations
2. 02*

   Impeded Dark Matter

   Joachim Kopp (1)🇩🇪 · Jia Liu (1)🇩🇪 · Tracy R. Slatyer (2)🇺🇸 · Xiao-Ping Wang (1)🇩🇪 · Wei Xue (2) ((1) JGU Mainz, (2) MIT)🇺🇸

   We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario "Impeded Dark Matter". We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden $SU(2)$ sector, and a composite dark matter scenario based on a QCD-like dark sector.

   hep-phastro-ph.HEJHEP(2016)·67 citations
3. 03*

   String Theory and the Dark Glueball Problem

   James Halverson🇺🇸 · Brent D. Nelson🇺🇸 · Fabian Ruehle🇩🇪

   We study cosmological constraints on dark pure Yang-Mills sectors. Dark glueballs are overproduced for large regions of ultraviolet parameter space. The problem may be alleviated in two ways: via a large preferential reheating into the visible sector, motivating certain inflation or modulus decay models, or via decays into axions or moduli, which are strongly constrained by nucleosynthesis and $\Delta N_{\text{eff}}$ bounds. String models frequently have multiple hidden Yang-Mills sectors, which are subject to even stronger constraints due to the existence of multiple dark glueballs.

   hep-phhep-thPRD(2017)·83 citations
4. 04*

   Axial Vector $Z^{\prime }$ and Anomaly Cancellation

   Ahmed Ismail🇺🇸 · Wai-Yee Keung🇺🇸 · Kuo-Hsing Tsao🇺🇸 · James Unwin🇺🇸

   Whilst the prospect of new $Z^{\prime }$ gauge bosons with only axial couplings to the Standard Model (SM) fermions is widely discussed, examples of anomaly-free renormalisable models are lacking in the literature. We look to remedy this by constructing several motivated examples. Specifically, we consider axial vectors which couple universally to all SM fermions, as well as those which are generation-specific, leptophilic, and leptophobic. Anomaly cancellation typically requires the presence of new coloured and charged chiral fermions, and we argue that in a large class of models masses of these new states are expected to be comparable to that of the axial vector. Finally, an axial vector mediator could provide a portal between SM and hidden sector states, and we also consider the possibility that the axial vector couples to dark matter. If the dark matter relic density is set due to freeze-out via the axial vector, this strongly constrains the parameter space.

   hep-phNPB(2017)·69 citations
5. 05*

   On the Use of the Tsallis Distribution at LHC Energies

   J. Cleymans🇿🇦

   Numerous papers have appeared recently showing fits to transverse momentum ($p_T$) spectra measured at the Large Hadron Collider (LHC) in proton - proton collisions.This talk focuses on the fits extending to very large values of the transverse momentum with $p_T$ values up to 200 GeV/c as measured by the ATLAS and CMS collaborations at $\sqrt{s}$ = 0.9 and 7 TeV. A thermodynamically consistent form of the Tsallis distribution is used for fitting the transverse momentum spectra at mid-rapidity. The fits based on the proposed distribution provide an excellent description over 14 orders of magnitude. Despite this success, an ambiguity is noted concerning the determination of the parameters in the Tsallis distribution. This prevents drawing firm conclusions as to the universality of the parameters appearing in the Tsallis distribution.

   hep-phJ.Phys.Conf.Ser.(2017)·31 citations
6. 06*

   Residual Non-Abelian Dark Matter and Dark Radiation

   P. Ko🇰🇷 · Yong Tang🇰🇷

   We propose a novel particle physics model in which vector dark matter (VDM) and dark radiation (DR) originate from the same non-Abelian dark sector. We show an illustrating example where dark $SU(3)$ is spontaneously broken into $SU(2)$ subgroup by the nonzero vacuum expectation value of a complex scalar in fundamental representation of $SU(3)$. The massless gauge bosons associated with the residual unbroken $SU(2)$ constitute DR and help to relieve the tension in Hubble constant measurements between $\text{Planck}$ and Hubble Space Telescope. In the meantime, massive dark gauge bosons associated with the broken generators are VDM candidates. Intrinsically, this non-Abelian VDM can interact with non-Abelian DR in the cosmic background, which results in a suppressed matter power spectrum and leads to a smaller ${\sigma }_8$ for structure formation.

   hep-phastro-ph.COPLB(2017)·79 citations
7. 07*

   Top-squark in natural SUSY under current LHC run-2 data

   Chengcheng Han🇯🇵 · Jie Ren🇨🇳 · Lei Wu🇦🇺 · Jin Min Yang🇨🇳 · Mengchao Zhang🇰🇷

   We utilize the recent LHC-13 TeV data to study the lower mass bound on top-squark (stop) in natural supersymmetry. We recast the LHC sparticle inclusive search of $(\ge 1)\mathrm{jets}+E_T^{miss}$ with ${\alpha }_T$ variable, the direct stop pair search (1-lepton channel and all-hadronic channel) and the monojet analyses. We find that these searches are complementary depending on stop and higgsino masses: for a heavy stop the all-hadronic stop pair search provides the strongest bound, for an intermediate stop the inclusive SUSY analysis with ${\alpha }_T$ variable is most efficient, while for a compressed stop-higgsino scenario the monojet search plays the key role. Finally, the lower mass bound on a stop is: (i) 320 GeV for compressed stop-higgsino scenario (mass splitting less than 20 GeV); (ii) 765 (860) GeV for higgsinos lighter than 300 (100) GeV.

   hep-phhep-exEPJC(2017)·35 citations
8. 08*

   Heavy-Meson Decay Constants: QCD Sum-Rule Glance at Isospin Breaking

   Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇷🇺 · Silvano Simula🇮🇹

   QCD sum rules for decay constants of heavy mesons with $u$ or $d$ quark yield for $B$ mesons much less isospin breaking than lattice QCD but good agreement for $D$ mesons.

   hep-phhep-latnucl-thEPJ Web Conf.(2016)·3 citations
9. 09*

   Solar neutrinos: Oscillations or No-oscillations?

   A. Yu. Smirnov🇩🇪

   The Nobel prize in physics 2015 has been awarded "... for the discovery of neutrino oscillations which show that neutrinos have mass". While SuperKamiokande (SK), indeed, has discovered oscillations, SNO observed effect of the adiabatic (almost non-oscillatory) flavor conversion of neutrinos in the matter of the Sun. Oscillations are irrelevant for solar neutrinos apart from small ${\nu }_e$ regeneration inside the Earth. Both oscillations and adiabatic conversion do not imply masses uniquely and further studies were required to show that non-zero neutrino masses are behind the SNO results. Phenomena of oscillations (phase effect) and adiabatic conversion (the MSW effect driven by the change of mixing in matter) are described in pedagogical way.

   hep-phastro-ph.SRhep-ex59 citations
10. 10*

    Dark matter in GUT inspired $Z^{\prime }$ portal scenarios

    Mathias Pierre🇫🇷

    We consider simple dark matter extensions of the standard model in $Z^{\prime }$ portal scenarios inspired by grand unification theory constructions and we study the phenomenology of such models by considering Spin Dependent and Spin Independent direct detection constraints, confronting the canonical thermally produced dark matter scenario and we show that in this simple framework the combination and the complementary of these constraints is a powerful tool to derive stringent bounds and to reduce the viable parameter space of the model.

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

    An investgation on the electron's EDM from the electron's MDM

    N. Panza🇧🇷 · Y. M. P. Gomes🇧🇷 · J. A. Helayël🇧🇷

    We pursue, in this contribution, an investigation of the contribution of the electron's magnetic dipole moment (MDM) to the electron's electric dipole moment (EDM) (or the charged leptons, more generally) in the framework of the Born-Infeld Electrodynamics and in a gravity background with a non-vanishing cosmological constant, where CP-symmetry is broken down. Our point of view consist in associating a non-trivial EDM to a non-symmetry of the charge distribution of the elementary particle under consideration. The bound on the electron's EDM published in 2014 is used to constrain the coupling parameter of the electromagnetic sector to the scalar curvature of the space-time in the case we consider gravity to be responsible for the asymmetry in the distribution.

    hep-phhep-th0 citations
12. 12*

    Unveiling the nucleon tensor charge at Jefferson Lab: A study of the SoLID case

    Zhihong Ye🇺🇸 · Nobuo Sato🇺🇸 · Kalyan Allada🇺🇸 · Tianbo Liu🇺🇸 · Jian-Ping Chen🇺🇸 · Haiyan Gao🇺🇸 · Zhong-Bo Kang🇺🇸 · Alexei Prokudin🇺🇸 · Peng Sun🇺🇸 · Feng Yuan🇺🇸

    Future experiments at the Jefferson Lab 12 GeV upgrade, in particular, the Solenoidal Large Intensity Device (SoLID), aim at a very precise data set in the region where the partonic structure of the nucleon is dominated by the valence quarks. One of the main goals is to constrain the quark transversity distributions. We apply recent theoretical advances of the global QCD extraction of the transversity distributions to study the impact of future experimental data from the SoLID experiments. Especially, we develop a simple strategy based on the Hessian matrix analysis that allows one to estimate the uncertainties of the transversity quark distributions and their tensor charges extracted from SoLID data simulation. We find that the SoLID measurements with the proton and the effective neutron targets can improve the precision of the u- and d-quark transversity distributions up to one order of magnitude in the range 0.05 < x < 0.6.

    hep-phhep-exnucl-exnucl-thPLB(2017)·61 citations
13. 13*

    NLO cross sections in 4 dimensions without DREG

    R. J. Hernández-Pinto🇲🇽 · F. Driencourt-Mangin🇪🇸 · G. Rodrigo🇪🇸 · G. F. R. Sborlini🇪🇸

    In this review, we present a new method for computing physical cross sections at NLO accuracy in QCD without using the standard Dimensional Regularisation. The algorithm is based on the Loop-Tree Duality theorem, which allow us to obtain loop integrals as a sum of phase-space integrals; in this way, transforming loop integrals into phase-space integrals, we propose a method to merge virtual and real contributions in order to find observables at NLO in $d=4$ space-time dimensions. In addition, the strategy described is used for computing the ${\gamma }^{\ast }\to q\bar{q}(g)$ process. A more detailed discussion related on this topic can be found in Ref [1].

    hep-phJ.Phys.Conf.Ser.(2016)·4 citations
14. 14*

    Global extraction of the parton-to-pion fragmentation functions at NLO accuracy in QCD

    R. J. Hernández-Pinto🇲🇽 · M. Epele🇦🇷 · D. de Florian🇦🇷 · R. Sassot🇦🇷 · M. Stratmann🇩🇪

    In this review, we discuss the results on the parton-to-pion fragmentation functions obtained in a combined NLO fit to data of single-inclusive hadron production in electron-positron annihilation, proton-proton collisions, and lepton-nucleon deep-inelastic scattering. A more complete discussion can be found in Ref. [1].

    hep-phJ.Phys.Conf.Ser.(2016)·3 citations
15. 15*

    An advanced precision analysis of the SM vacuum stability

    A.V. Bednyakov🇷🇺

    The talk is devoted to the problem of stability of the Standard Model vacuum. The effective potential for the Higgs field, which can potentialy exhibit additional, deeper minimum, is considered as a convenient tool for addressing the problem. Different methods and approximations used to calculate the potential are considered. Special attention is paid to the renomalization-group approach that allows one to carry out three-loop analysis of the problem. By means of an explicit gauge-independent procedure the absolute stability bounds on the observed Higgs and top-quark masses are derived. The importance of high-order corrections is demonstrated. In addition, potential metastablity of the SM is discussed together with modifications of the analysis due to some New Physics.

    hep-phPhys.Part.Nucl.(2017)·2 citations
16. 16*

    Spectroscopy of singly, doubly, and triply bottom baryons

    Ke-Wei Wei🇨🇳 · Bing Chen🇨🇳 · Na Liu🇨🇳 · Qian-Qian Wang🇨🇳 · Xin-Heng Guo🇨🇳

    Recently, some singly bottom baryons have been established experimentally, but none of doubly or triply bottom baryons has been observed. Under the Regge phenomenology, the mass of a ground state unobserved doubly or triply bottom baryon is expressed as a function of masses of the well established light baryons and singly bottom baryons. Then, the values of Regge slopes and Regge intercepts for baryons containing one, two, or three bottom quarks are calculated. After that, masses of the orbitally excited singly, doubly, and triply bottom baryons are estimated. Our predictions may be useful for the discovery of these baryons and the $J^P$ assignment of them.

    hep-phPRD(2017)·85 citations
17. 17*

    Nuclear Physics and Astrophysics of Neutrino Oscillations

    A.B. Balantekin (Wisconsin U., Madison)🇺🇸

    For a long time very little experimental information was available about neutrino properties, even though a minute neutrino mass has intriguing cosmological and astrophysical implications. This situation has changed in recent decades: intense experimental activity to measure many neutrino properties took place. Some of these developments and their implications for astrophysics and cosmology are briefly reviewed with a particular emphasis on neutrino magnetic moments and collective neutrino oscillations

    ↳ nucl-thastro-ph.COhep-phJPS Conf.Proc.(2017)·1 citation
18. 18*

    A dilaton-pion mass relation

    Aya Kasai🇯🇵 · Ken-ichi Okumura🇯🇵 · Hiroshi Suzuki🇯🇵

    Recently, Golterman and Shamir presented an effective field theory which is supposed to describe the low-energy physics of the pion and the dilaton in an $SU(N_c)$ gauge theory with $N_f$ Dirac fermions in the fundamental representation. By employing this formulation with a slight but important modification, we derive a relation between the dilaton mass squared~$m_{\tau }^2$, with and without the fermion mass~$m$, and the pion mass squared~$m_{\pi }^2$ to the leading order of the chiral logarithm. This is analogous to a similar relation obtained by Matsuzaki and~Yamawaki on the basis of a somewhat different low-energy effective field theory. Our relation reads $m_{\tau }^2=m_{\tau }^2{|}_{m=0}+K{N}_f{\hat{f}}_{\pi }^2{m}_{\pi }^2/(2{\hat{f}}_{\tau }^2)+O(m_{\pi }^4\ln m_{\pi }^2)$ with~$K=9$, where ${\hat{f}}_{\pi }$ and~${\hat{f}}_{\tau }$ are decay constants of the pion and the dilaton, respectively. This mass relation differs from the one derived by Matsuzaki and~Yamawaki on the points that $K=(3-{\gamma }_m)(1+{\gamma }_m)$, where ${\gamma }_m$ is the mass anomalous dimension, and the leading chiral logarithm correction is~$O(m_{\pi }^2\ln m_{\pi }^2)$. For~${\gamma }_m\sim 1$, the value of the decay constant~${\hat{f}}_{\tau }$ estimated from our mass relation becomes $\sim 50\%$ larger than ${\hat{f}}_{\tau }$ estimated from the relation of Matsuzaki and~Yamawaki.

    ↳ hep-lathep-phhep-th44 citations
19. 19*

    The Fermi Large Area Telescope as a Galactic Supernovae Axionscope

    Manuel Meyer🇸🇪 · Maurizio Giannotti🇺🇸 · Alessandro Mirizzi🇮🇹 · Jan Conrad🇸🇪 · Miguel Sanchez-Conde🇸🇪

    In a Galactic core-collapse supernova (SN), axionlike particles (ALPs) could be emitted via the Primakoff process and eventually convert into $\gamma$ rays in the magnetic field of the Milky Way. From a data-driven sensitivity estimate, we find that, for a SN exploding in our Galaxy, the Fermi Large Area Telescope (LAT) would be able to explore the photon-ALP coupling down to $g_{a\gamma }\simeq 2\times 10^{-13}$GeV${}^{-1}$ for an ALP mass $m_a\lesssim 10^{-9}$eV. These values are out of reach of next generation laboratory experiments. In this event, the Fermi LAT would probe large regions of the ALP parameter space invoked to explain the anomalous transparency of the Universe to $\gamma$ rays, stellar cooling anomalies, and cold dark matter. If no $\gamma$-ray emission were to be detected, Fermi-LAT observations would improve current bounds derived from SN1987A by more than one order of magnitude.

    ↳ astro-ph.HEhep-phPRL(2017)·139 citations
20. 20*

    A Noncompact Weyl-Einstein-Yang-Mills Model: A Semiclassical Quantum Gravity

    Suat Dengiz🇺🇸

    We construct and study perturbative unitarity (i.e., ghost and tachyon analysis) of a $3+1$-dimensional noncompact Weyl-Einstein-Yang-Mills model. The model describes a local noncompact Weyl's scale plus $SU(N)$ phase invariant Higgs-like field, conformally coupled to a generic Weyl-invariant dynamical background. Here, the Higgs-like sector generates the Weyl's conformal invariance of system. The action does not admit any dimensionful parameter and genuine presence of de Sitter vacuum spontaneously breaks the noncompact gauge symmetry in an analogous manner to the Standard Model Higgs mechanism. As to flat spacetime, the dimensionful parameter is generated within the dimensional transmutation in quantum field theories, and thus the symmetry is radiatively broken through the one-loop Effective Coleman-Weinberg potential. We show that the mere expectation of reducing to Einstein's gravity in the broken phases forbids anti-de Sitter space to be its stable vacua. The model is unitary in de Sitter and flat vacua around which a massless graviton, $N^2-1$ massless scalar bosons, $N$ massless Dirac fermions, $N^2-1$ Proca-type massive Abelian and non-Abelian vector bosons are generically propagated.

    ↳ hep-thgr-qchep-phAnnals Phys.(2017)·13 citations
21. 21*

    Particle production and chemical freezeout from the hybrid UrQMD approach at NICA energies

    Abdel Nasser Tawfik (Egyptian Ctr. Theor. Phys., Cairo and WLCAPP, Cairo)🇪🇬 · Loutfy I. Abou-Salem🇪🇬 · Asmaa G. Shalaby🇪🇬 · Mahmoud Hanafy (Benha U)🇪🇬 · Alexander Sorin (JINR, Dubna and Moscow Phys. Eng. Inst.)🇷🇺 · Oleg Rogachevsky🇷🇺 · Werner Scheinast (JINR, Dubna)🇷🇺

    The energy dependence of various particle ratios is calculated within the Ultra-Relativistic Quantum Molecular Dynamics approach and compared with the hadron resonance gas (HRG) model and measurements from various experiments, including RHIC-BES, SPS and AGS. It is found that the UrQMD particle ratios agree well with the experimental results at the RHIC-BES energies. Thus, we have utilized UrQMD in simulating particle ratios at other beam energies down to 3 GeV, which will be accessed at NICA and FAIR future facilities. We observe that the particle ratios for crossover and first-order phase transition, implemented in the hybrid UrQMD v3.4, are nearly indistinguishable, especially at low energies (at large baryon chemical potentials or high density).

    ↳ nucl-thhep-exhep-phEPJA(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.