HEP Phenomenology·hep-ph

Wed·Jan 4, 2017Wednesday·January 4, 2017

14 papers—9 primary·5 cross-listed·reconstructed*

01*
Scalar Unparticle Signals at the LHC
T.M. Aliev (METU)🇹🇷 · Selcuk Bilmis (METU)🇹🇷 · Melih Solmaz (UCSB)🇺🇸 · Ismail Turan (METU)🇹🇷
If the scale invariance exists in nature, the so-called unparticle physics may become part of reality. The only way to refute or confirm this idea is through the experiments one of which is the Large Hadron Collider (LHC). One of the peculiar properties of the unparticle stuff is that it gives striking multi-photon signals which has been studied through only the unparticle self-interactions. By considering not only the self-interactions of unparticles but also all the other possible contributions, which are dominant, a detailed study of the processes, within a scalar unparticle scenario, $pp \to 4 γ$ , $pp \to 2 γ 2 g$ , $pp \to 2 γ 2 ℓ$ , $pp \to 4 e$ , $pp \to 4 μ$ and $pp \to 2 e 2 μ$ at $s = 14$ TeV at the LHC is carried out. We use basic selection cuts and analyze various distributions to discriminate the signals over the Standard Model backgrounds and discuss what seems to be the most likely channel among the above ones for an indirect manifestation of unparticle effects. We follow a new approach to tackle the issue with the three-point correlation function for the scalar unparticle self-interactions. We also obtain the exclusion region in the unparticle parameter space from the available two-photon data of the LHC.
hep-phPRD(2017)·15 citations
02*
Scalegenesis via dynamically induced multiple seesaws
Hiroyuki Ishida🇹🇼 · Shinya Matsuzaki🇯🇵 · Shohei Okawa🇯🇵 · Yuji Omura🇯🇵
We propose a model which accounts for the dynamical origin of the electroweak symmetry breaking (EWSB), directly linking to the mass generation of dark matter (DM) candidate and active neutrinos. The standard model (SM) is weakly charged under the $U (1)_{B - L}$ gauge symmetry, in conjunction with newly introduced three right-handed Majorana neutrinos and the $U (1)_{B - L}$ Higgs. The model is built on the classical scale invariance, that is dynamically broken by a new strongly coupled sector, what is called the hypercolor (HC) sector, which is also weakly coupled to the $U (1)_{B - L}$ gauge. At the HC strong scale, the simultaneous breaking of the EW and $U (1)_{B - L}$ gauge symmetries is triggered by dynamically induced multiple seesaw mechanisms, namely bosonic seesaw mechanisms. Thus, all the origins of masses are provided singly by the HC dynamics: that is what we call the dynamical scalegenesis. We also find that an HC baryon, with mass on the order of a few TeV, can be stabilized by the HC baryon number and the $U (1)_{B - L}$ charge, so identified as a DM candidate. The relic abundance of the HC-baryon DM can be produced dominantly via the bosonic-seesaw portal process, and the HC-baryon DM can be measured through the large magnetic moment coupling generated from the HC dynamics, or the $U (1)_{B - L}$ -gauge boson portal in direct detection experiments.
hep-phastro-ph.HEhep-thPRD(2017)·14 citations
03*
Gravitational Instabilities of the Cosmic Neutrino Background with Non-zero Lepton Number
Neil D. Barrie🇦🇺 · Archil Kobakhidze🇦🇺
We argue that a cosmic neutrino background that carries non-zero lepton charge develops gravitational instabilities. Fundamentally, these instabilities are related to the mixed gravity-lepton number anomaly. We have explicitly computed the gravitational Chern-Simons term which is generated quantum-mechanically in the effective action in the presence of a lepton number asymmetric neutrino background. The induced Chern-Simons term has a twofold effect: (i) gravitational waves propagating in such a neutrino background exhibit birefringent behaviour leading to an enhancement/suppression of the gravitational wave amplitudes depending on the polarisation, where the magnitude of this effect is related to the size of the lepton asymmetry; (ii) Negative energy graviton modes are induced in the high frequency regime, which leads to very fast vacuum decay producing, e.g., positive energy photons and negative energy gravitons. From the constraint on the present radiation energy density, we obtain an interesting bound on the lepton asymmetry of the universe.
hep-phastro-ph.COPLB(2017)·12 citations
04*
Bottomonia suppression in an anisotropic quark-gluon plasma
Radoslaw Ryblewski🇵🇱
A brief review of recent studies on suppression of bottomonia in an anisotropic quark-gluon plasma created in heavy-ion collisions at the LHC is presented. A reasonable agreement between the model predictions for the inclusive $R_{AA}$ suppression factor and the preliminary CMS experimental data is found. The values of the shear viscosity to the entropy density ratio extracted from the comparison with the data lie between one and two times the gauge/gravity duality lower bound. These values agree very well with the fluid dynamical fits to the light hadron correlation data and confirm that the quark-gluon plasma is a nearly-perfect fluid.
hep-phnucl-thEPJ Web Conf.(2017)·0 citations
05*
Dispersive approach to QCD and hadronic contributions to electroweak observables
A.V.Nesterenko🇷🇺
The dispersive approach to QCD is briefly overviewed and its application to the assessment of hadronic contributions to electroweak observables is discussed.
hep-phhep-latEPJ Web Conf.(2017)·7 citations
06*
How Large is the Contribution of Excited Mesons in Coupled-Channel Effects?
Yu Lu🇨🇳 · Muhammad Naeem Anwar🇨🇳 · Bing-Song Zou🇨🇳
We study the excited $B$ mesons' contributions to the coupled-channel effects under the framework of $^{3} P_{0}$ model for the bottomonium. Contrary to what has been widely accepted, the contributions of $P$ wave $B$ mesons are generally the largest and this result is independent of the potential parameters to some extent. We also push the calculation beyond $B (1 P)$ and carefully analyze the contributions of $B (2 S)$ . A form factor is a key ingredient to suppress the contributions of $B (2 S)$ for low lying bottomonia. However, this suppression mechanism is not efficient for highly excited bottomonia such as $Υ (5 S)$ and $Υ (6 S)$ . We give explanations why this difficulty happens to $^{3} P_{0}$ model and suggest analyzing flux-tube breaking model for the full calculation of coupled-channel effects.
hep-phPRD(2017)·28 citations
07*
epsilon: A tool to find a canonical basis of master integrals
Mario Prausa🇩🇪
In 2013, Henn proposed a special basis for a certain class of master integrals, which are expressible in terms of iterated integrals. In this basis, the master integrals obey a differential equation, where the right hand side is proportional to $ϵ$ in $d = 4 - 2 ϵ$ space-time dimensions. An algorithmic approach to find such a basis was found by Lee. We present the tool epsilon, an efficient implementation of Lee's algorithm based on the Fermat computer algebra system as computational backend.
hep-phComput.Phys.Commun.(2017)·157 citations
08*
Dark SU(N) glueball stars on fluid branes
Roldao da Rocha🇧🇷
The glueball dark matter, in the pure SU(N) Yang-Mills theory, engenders dark SU(N) stars that comprise self-gravitating compact configurations of scalar glueball fields. Corrections to the highest frequency of gravitational wave radiation emitted by dark SU(N) star mergers on a fluid brane with variable tension, implemented by the minimal geometric deformation, are derived and their consequences analysed. Hence, dark SU(N) stars mergers on a fluid brane-world are shown to be better detectable by the LIGO and the eLISA experiments.
hep-phgr-qchep-thPRD(2017)·101 citations
09*
A different approach to electroweak interactions without using any $S U (2)_{L}$ doublet
Anirban Karan🇮🇳
We know that demanding $S U (2)_{L} \times U (1)_{Y}$ gauge symmetry of Lagrangian is a "sufficient" condition to describe electroweak interactions, however, in this paper, we have tried to find whether it's a "necessary" condition or not. We have used a different approach to describe electroweak interactions without using any $S U (2)_{L}$ doublet or $S U (2)_{L}$ generator and incorporate some new physics aspects into theory. In this method, we only need local gauge invariance of Lagrangian under a "generalised $U (1)_{Q}$ gauge transformation", where $Q$ is electric charge (not to be confused with usual $U (1)$ transformation). Under this gauge transformation, all charged fields including charged gauge bosons transform as $H_{(μ)} \to H_{(μ)} e^{i q_{h} θ}$ and all neutral gauge bosons transforms as $V_{μ} \to V_{μ} + Λ \partial_{μ} θ$ . Nevertheless, $S U (2)_{L}$ symmetry can be restored by imposing constraints on some parameters and thus standard model can be considered as a special case of this model. Hence, it turns out that $S U (2)_{L} \times U (1)_{Y}$ gauge symmetry is a "sufficient" but "not necessary" condition for electroweak interactions.
hep-phhep-th0 citations
10*
N=2 -> 0 super no-scale models and moduli quantum stability
Costas Kounnas🇫🇷 · Herve Partouche🇫🇷
We consider a class of heterotic N=2 -> 0 super no-scale Z_2-orbifold models. An appropriate stringy Scherk-Schwarz supersymmetry breaking induces tree level masses to all massless bosons of the twisted hypermultiplets and therefore stabilizes all twisted moduli. At high supersymmetry breaking scale, the tachyons that occur in the N=4 -> 0 parent theories are projected out, and no Hagedorn-like instability takes place in the N=2 -> 0 models (for small enough marginal deformations). At low supersymmetry breaking scale, the stability of the untwisted moduli is studied at the quantum level by taking into account both untwisted and twisted contributions to the 1-loop effective potential. The latter depends on the specific branch of the gauge theory along which the background can be deformed. We derive its expression in terms of all classical marginal deformations in the pure Coulomb phase, and in some mixed Coulomb/Higgs phases. In this class of models, the super no-scale condition requires having at the massless level equal numbers of untwisted bosonic and twisted fermionic degrees of freedom. Finally, we show that N=1 -> 0 super no-scale models are obtained by implementing a second Z_2 orbifold twist on N=2 -> 0 super no-scale Z_2-orbifold models.
↳ hep-thgr-qchep-phNPB(2017)·37 citations
11*
Nonperturbative Transverse Momentum Effects in Dihadron and Direct Photon-Hadron Angular Correlations
J.D. Osborn (for the PHENIX Collaboration)🇺🇸
Two-particle angular correlations have long been used as an observable for measuring the initial-state partonic transverse momentum $k_{T}$ . Sensitivity to this small transverse momentum scale allows nonperturbative transverse momentum dependent effects to be probed in high $p_{T}$ dihadron and direct photon-hadron correlations. The observable $p_{o u t}$ , the out-of-plane transverse momentum component from a near-side $π^{0}$ or direct photon, is sensitive to initial-state $k_{T}$ and final-state fragmentation transverse momentum $j_{T}$ and thus can probe nonperturbative transverse-momentum-dependent effects. In the transverse-momentum-dependent framework, nearly back-to-back particle production in $p$ + $p$ collisions with a measured final-state hadron has been predicted to break factorization due to the possibility of gluon exchanges with colored remnants in the initial and final states. For this reason, the interacting partons are predicted to be correlated; however, there is so far no quantitative prediction for the magnitude of such effects. In this talk, recent measurements of dihadron and direct-photon hadron correlations in $p$ + $p$ collisions at $s$ =510 GeV at the PHENIX experiment will be presented.
↳ hep-exhep-ph0 citations
12*
A Complete Diagrammatic Implementation of the Kinoshita-Lee-Nauenberg Theorem at Next-to-Leading Order
Abdullah Khalil🇿🇦 · W. A. Horowitz🇿🇦
We show for the first time in over 50 years how to correctly apply the Kinoshita-Lee-Nauenberg theorem diagrammatically in a next-to-leading order scattering process. We improve on previous works by including all initial and final state soft radiative processes, including absorption and an infinite sum of partially disconnected amplitudes. Crucially, we exploit the Monotone Convergence Theorem to prove that our delicate rearrangement of this formally divergent series is correct. This rearrangement yields a factorization of the infinite contribution from the initial state soft photons that then cancels in the physically observable cross section. We derive the first complete next-to-leading order, high-energy Rutherford elastic scattering cross section in the $MS$ renormalization scheme as an explicit example of our procedure.
↳ hep-thhep-phnucl-th4 citations
13*
On the inverse problem for extragalactic cosmic ray nuclei with energies $1 0^{18}$ to $1 0^{20}$ eV
V.N.Zirakashvili🇷🇺 · S.I.Rogovaya🇷🇺 · V.S.Ptuskin🇷🇺 · E.G.Klepach🇷🇺
The inverse problem of cosmic ray transport of ultra-high energy cosmic rays is considered. The analysis of Auger data on energy spectrum, energy dependence of mean logarithm of atomic mass number and its variance allows definite conclusions on the shape of the source spectrum in the frameworks of the inverse problem approach. The discussion on regularization procedure for considered ill-posed problem is presented.
↳ astro-ph.HEhep-ph0 citations
14*
SNRs W28 and W44: old cosmic ray accelerators in molecular clouds
V.N. Zirakashvili🇷🇺 · V.S. Ptuskin🇷🇺
Nonlinear model of diffusive shock acceleration is used for investigation of the particle acceleration in old supernova remnants W28 and W44. We modeled the hydrodynamical evolution of the remnants, shock modification and streaming instability produced by accelerated particles. Comparison with available radio and gamma-ray data is given.
↳ astro-ph.HEhep-ph6 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.