PaperPanorama

HEP Phenomenology·hep-ph

Mon·Dec 28, 2015

15 papers—11 primary·4 cross-listed·reconstructed*

All15Primary11Cross-lists4
  1. 01*

    LHC diphoton excess from colorful resonances

    Jia Liu (1)🇩🇪 · Xiao-Ping Wang (1)🇩🇪 · Wei Xue (2) ((1) PRISMA/MITP, Johannes Gutenberg University Mainz, (2) CTP, Massachusetts Institute of Technology)🇺🇸

    Motivated by the possible diphoton excess around observed by ATLAS and CMS at , we consider a coloron model from spontaneously breaking to the Standard Model . A colored massive vector boson is resonantly produced by in proton collision, followed by a colored scalar cascade decay. This process gives two photons and one jet in the final states. And the kinetic edge of the two photons can be an interpretation of the diphoton excess, while satisfying the dijet, , jet+photon resonance constraints. In this model, due to the large mass of vector resonance, the parton luminosity function ratio between and can be quite large. Therefore, the diphoton excess has not been observed at search. On the other hand, having all the new particles color-charged around , this model predicts new signals at the LHC, which can be validated soon.

    hep-ph90 citations
  2. 02*

    Electroweak Vacuum Stability and Diphoton Excess at 750 GeV

    Jue Zhang🇨🇳 · Shun Zhou🇨🇳

    Recently, both ATLAS and CMS collaborations at the CERN Large Hadron Collider (LHC) have announced their observations of an excess of diphoton events around the invariant mass of with a local significance of and , respectively. In this paper, we interpret the diphoton excess as the on-shell production of a real singlet scalar in the channel. To accommodate the observed production rate, we further introduce a vector-like fermion , which is carrying both color and electric charges. The viable regions of model parameters are explored for this simple extension of the Standard Model (SM). Moreover, we revisit the problem of electroweak vacuum stability in the same scenario, and find that the requirement for the electroweak vacuum stability up to high energy scales imposes serious constraints on the Yukawa coupling of the vector-like fermion and the quartic couplings of the SM Higgs boson and the new singlet scalar. Consequently, a successful explanation for the diphoton excess and the absolute stability of electroweak vacuum cannot be achieved simultaneously in this economical setup.

    hep-phCPC(2016)·100 citations
  3. 03*

    The 750 GeV Diphoton Excess as a First Light on Supersymmetry Breaking

    J.A. Casas🇪🇸 · J.R. Espinosa🇪🇸 · J.M. Moreno🇪🇸

    One of the most exciting explanations advanced for the recent diphoton excess found by ATLAS and CMS is in terms of sgoldstino decays: a signal of low-energy supersymmetry-breaking scenarios. The sgoldstino, a scalar, couples directly to gluons and photons, with strength related to gaugino masses, that can be of the right magnitude to explain the excess. However, fitting the suggested resonance width, Gamma ~ 45 GeV, is not so easy. In this paper we explore efficient possibilities to enhance the sgoldstino width, via the decay into two Higgses, two Higgsinos and through mixing between the sgoldstino and the Higgs boson. In addition, we present an alternative and more efficient mechanism to generate a mass splitting between the scalar and pseudoscalar components of the sgoldstino, which has been suggested as an interesting alternative explanation to the apparent width of the resonance.

    hep-phPLB(2016)·92 citations
  4. 04*

    750 GeV Diphotons: Implications for Supersymmetric Unification

    Lawrence J. Hall🇺🇸 · Keisuke Harigaya🇺🇸 · Yasunori Nomura🇺🇸

    A recent signal of 750 GeV diphotons at the LHC can be explained within the framework of supersymmetric unification by the introduction of vector quarks and leptons with Yukawa couplings to a singlet S that describes the 750 GeV resonance. We study the most general set of theories that allow successful gauge coupling unification, and find that these Yukawa couplings are severely constrained by renormalization group behavior: they are independent of ultraviolet physics and flow to values at the TeV scale that we calculate precisely. As a consequence the vector quarks and leptons must be light; typically in the region of 375 GeV to 700 GeV, and in certain cases up to 1 TeV. The 750 GeV resonance may have a width less than the experimental resolution; alternatively, with the mass splitting between scalar and pseudoscalar components of S arising from one-loop diagrams involving vector fermions, we compute an apparent width of 10s of GeV.

    hep-phhep-exJHEP(2016)·112 citations
  5. 05*

    The Axiverse induced Dark Radiation Problem

    Bobby Samir Acharya🇬🇧 · Chakrit Pongkitivanichkul🇬🇧

    The string/ theory Axiverse -- a plethora of very light Axion Like Particles (ALPs) with a vast range of masses -- is arguably a generic prediction of string/ theory. String/ theory also tends to predict that the early Universe is dominated by moduli fields. When the heavy moduli decay, before nucleosynthesis, they produce dark radiation in the form of relativistic ALPs. Generically one estimates that the number of relativistic species grows with the number of axions in the Axiverse, in contradiction to the observations that . We explain this problem in detail and suggest some possible solutions to it. The simplest solution requires that the lightest modulus decays only into its own axion superpartner plus Standard Model particles and this severely constrains the moduli Kahler potential and mass matrix.

    hep-phastro-ph.COhep-thJHEP(2016)·41 citations
  6. 06*

    SIMP Spectroscopy

    Yonit Hochberg🇺🇸 · Eric Kuflik🇺🇸 · Hitoshi Murayama🇺🇸

    We study the interactions between strongly interacting massive particle dark matter and the Standard Model via a massive vector boson that is kinetically mixed with the hypercharge gauge boson. The relic abundance is set by 3-to-2 self-interactions of the dark matter, while the interactions with the vector mediator enable kinetic equilibrium between the dark and visible sectors. We show that a wide range of parameters is phenomenologically viable and can be probed in various ways. Astrophysical and cosmological constraints are evaded due to the p-wave nature of dark matter annihilation into visible particles, while direct detection methods using electron recoils can be sensitive to parts of the parameter space. In addition, we propose performing spectroscopy of the strongly coupled dark sector at e+e- colliders, where the energy of a mono-photon can track the resonance structure of the dark sector. Alternatively, some resonances may decay back into Standard Model leptons or jets, realizing `hidden valley' phenomenology at the LHC and ILC in a concrete fashion.

    hep-phJHEP(2016)·187 citations
  7. 07*

    Radiative neutrino mass model with degenerate right-handed neutrinos

    Shoichi Kashiwase🇯🇵 · Daijiro Suematsu🇯🇵

    The radiative neutrino mass model can relate neutrino masses and dark matter at a TeV scale. If we apply this model to thermal leptogenesis, we need to consider resonant leptogenesis at that scale. It requires both finely degenerate masses for the right-handed neutrinos and a tiny neutrino Yukawa coupling. We propose an extension of the model with a U(1) gauge symmetry, in which these conditions are shown to be simultaneously realized through a TeV scale symmetry breaking. Moreover, this extension can bring about a small quartic scalar coupling between the Higgs doublet scalar and an inert doublet scalar which characterizes the radiative neutrino mass generation. It also is the origin of the symmetry which guarantees the stability of dark matter. Several assumptions which are independently supposed in the original model are closely connected through this extension.

    hep-phEPJC(2016)·8 citations
  8. 08*

    Limits on Excited Quarks from the ATLAS Multi-jet Search

    Ning Zhou🇨🇳 · Kechen Wang🇨🇳 · Kuhan Wang🇨🇦

    We interpret the recent ATLAS multi-jet search results using 20.3 fb-1 data at sqrt(s)=8 TeV in the context of searching for excited quarks. Within the effective field theory framework, using the null results of that search, our analysis shows that the excited quark mass below 5 TeV can be excluded at the 95% confidence level. Our analysis also indicates that when the validation of effective field theory is considered, the limit can be largely compromised.

    hep-ph0 citations
  9. 09*

    Quantum processes in short and intensive electromagnetic fields

    Alexander I. Titov🇷🇺 · Burkhard Kampfer🇩🇪 · Atsushi Hosaka🇯🇵 · Hideaki Takabe🇯🇵

    This work provides an overview of our recent results in studying two most important and widely discussed quantum processes: electron-positron pairs production off a probe photon propagating through a polarized short-pulsed electromagnetic (e.g.\ laser) wave field or generalized Breit-Wheeler process, and a single a photon emission off an electron interacting with the laser pules, so-called non-linear Compton scattering. We show that the probabilities of particle production in both processes are determined by interplay of two dynamical effects, where the first one is related to the shape and duration of the pulse and the second one is non-linear dynamics of the interaction of charged fermions with a strong electromagnetic field. We elaborate suitable expressions for the production probabilities and cross sections, convenient for studying evolution of the plasma in presence of strong electromagnetic fields

    hep-phPhys.Part.Nucl.(2016)·20 citations
  10. 10*

    Dark Matter Theories in the Light of Diphoton Excess

    Huayong Han🇨🇳 · Shaoming Wang🇨🇳 · Sibo Zheng🇨🇳

    A new type of dark matter (DM) theories are proposed in the light of the standard model (SM) singlet scalar which is responsible for the diphoton excess at the LHC Run 2. In the so-called -portal DM models, after taking into account the LHC constraints and DM direct detection limits, we show that in the perturbative framework DM as either a SM singlet scalar or Dirac fermion can be allowed in a wide mass range between 400 GeV and 3 TeV. The DM can be directly detected in SM multi-jets and missing energy.

    hep-phhep-ex74 citations
  11. 11*

    Covariance constraints for light front wave functions

    Dieter Müller🇭🇷

    Light front wave functions (LFWFs) are often utilized to model parton distributions and form factors where their transverse and longitudinal momenta are tied to each other in some manner that is often guided by convenience. On the other hand, the cross talk of transverse and longitudinal momenta is governed by Poincaré symmetry and thus popular LFWF models are often not usable to model more intricate quantities such as generalized parton distributions. In this contribution a closer look to this issue is given and it is shown how to overcome the issue for two--body LFWFs.

    hep-phhep-exFew Body Syst.(2016)·0 citations
  13. 13*

    CMB Constraint on Dark Matter Annihilation after Planck 2015

    Masahiro Kawasaki🇯🇵 · Kazunori Nakayama🇯🇵 · Toyokazu Sekiguchi🇰🇷

    We update the constraint on the dark matter annihilation cross section by using the recent measurements of the CMB anisotropy by the Planck satellite. We fully calculate the cascade of dark matter annihilation products and their effects on ionization, heating and excitation of the hydrogen, hence do not rely on any assumption on the energy fractions that cause these effects.

    ↳ astro-ph.COhep-phPLB(2016)·44 citations
  15. 15*

    Hadron multiplicities and chemical freeze-out conditions in proton-proton and nucleus-nucleus collisions

    V. Vovchenko🇩🇪 · V. V. Begun🇵🇱 · M. I. Gorenstein🇺🇦

    New results of the NA61/SHINE Collaboration at the CERN SPS on mean hadron multiplicities in proton-proton (p+p) interactions are analyzed within the transport models and the hadron resonance gas (HRG) statistical model. The chemical freeze-out parameters in p+p interactions and central Pb+Pb (or Au+Au) collisions are found and compared with each other in the range of the center of mass energy of the nucleon pair GeV. The canonical ensemble formulation of the HRG model is used to describe mean hadron multiplicities in p+p interactions and the grand canonical ensemble in central Pb+Pb and Au+Au collisions. The chemical freeze-out temperatures in p+p interactions are found to be larger than the corresponding temperatures in central nucleus-nucleus collisions.

    ↳ nucl-thhep-phPRC(2016)·126 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.