Tue·Jan 10, 2017Tuesday·January 10, 2017

1. 01*

   Non-Minimal Flavored ${\mathbf{S}}_3\otimes {\mathbf{Z}}_2$ Left-Right Symmetric Model

   Juan Carlos Gómez-Izquierdo🇲🇽

   We propose a non-minimal left-right symmetric model (LRSM) with Parity Symmetry where the fermion mixings arise as result of imposing an ${\mathbf{S}}_3\otimes {\mathbf{Z}}_2$ flavor symmetry, and an extra ${\mathbf{Z}}_2^e$ symmetry is considered to suppress some Yukawa couplings in the lepton sector. As a consequence, the effective neutrino mass matrix possesses approximately the $\mu -\tau$ symmetry. The breaking of the $\mu -\tau$ symmetry induces sizable non zero ${\theta }_{13}$, and the deviation of ${\theta }_{23}$ from $45^{\circ }$ is strongly controlled by an $ϵ$ free parameter and the complex neutrino masses. Then, an analytic study on the extreme Majorana phases is done since these turn out to be relevant to enhance or suppress the reactor and atmospheric angle. So that we have constrained the parameter space for the $ϵ$ parameter and the lightest neutrino mass that accommodate the mixing angles. The highlighted results are: a) the normal hierarchy is ruled out since the reactor angle comes out being tiny, for any values of the Majorana phases; b) for the inverted hierarchy there is one combination in the extreme phases where the values of the reactor and atmospheric angles are compatible up to $2,3\sigma$ of C. L., but the parameter space is tight; c) the model favors the degenerate ordering for one combination in the extreme Majorana phases. In this case, the reactor and atmospheric angle are compatible with the experimental data for a large set of values of the free parameters. Therefore, this model may be testable by the future result that the Nova and KamLAND-Zen collaborations will provide.

   hep-phEPJC(2017)·38 citations
2. 02*

   Muon-to-Electron Conversion in Mirror Fermion Model with Electroweak Scale Non-Sterile Right-handed Neutrinos

   P. Q. Hung🇺🇸 · Trinh Le🇺🇸 · Van Que Tran🇹🇼 · Tzu-Chiang Yuan🇹🇼

   The muon-to-electron conversion in nuclei like aluminum, titanium and gold is studied in the context of a class of mirror fermion model with non-sterile right-handed neutrinos having mass at the electroweak scale. At the limit of zero momentum transfer and large mirror lepton masses, we derive a simple formula to relate the conversion rate with the on-shell radiative decay rate of muon into electron. Current experimental limits (SINDRUM II) and projected sensitivities (Mu2e, COMET and PRISM) for the muon-to-electron conversion rates in various nuclei and latest limit from MEG for the radiative decay rate of muon into electron are used to put constraints on the parameter space of the model. Depending on the nuclei targets used in different experiments, for the mirror lepton mass in the range of 100 to 800 GeV, the sensitivities of the new Yukawa couplings one can probe in the near future are in the range of one tenth to one hundred-thousandth, depending on the mixing scenarios in the model.

   hep-phNPB(2018)·22 citations
3. 03*

   The new elastic scattering measurements of TOTEM --- are there hints for asymptotics?

   S.M. Troshin🇷🇺 · N.E. Tyurin🇷🇺

   We point out to another indication of the black-disk limit exceeding in hadron interactions found in the recent impact parameter analysis performed by the TOTEM Collaboration at $\sqrt{s}$=8 TeV and emphasise that this observation might be interpreted as a confirmation of the reflective scattering mode appearance at the LHC energies.

   hep-phEPJA(2017)·11 citations
4. 04*

   Photon radiation in $e^{+}{e}^{-}\to$ hadrons at low energies with CARLOMAT 3.1

   Fred Jegerlehner🇩🇪 · Karol Kolodziej🇵🇱

   We present a sample of results for the cross sections of several processes of low energetic $e^{+}{e}^{-}$ annihilation into final states containing pions accompanied by one or two photons, or a light lepton pair. The results, which have been obtained with a new version of a multipurpose Monte Carlo program CARLOMAT, labelled 3.1, demonstrate new capabilities of the program which, among others, include a possibility of taking into account either the initial or final state radiation separately, or both at a time, and a possibility of inclusion of the electromagnetic charged pion form factor for processes with charged pion pairs. We also discuss some problems related to the $U(1)$ electromagnetic gauge invariance.

   hep-phEPJC(2017)·10 citations
5. 05*

   $S$-wave resonance contributions to the $B_{(s)}^0\to {\eta }_c(2S){\pi }^{+}{\pi }^{-}$ in the perturbative QCD factorization approach

   Ai-Jun Ma🇨🇳 · Ya Li🇨🇳 · Wen-Fei Wang🇨🇳 · Zhen-Jun Xiao🇨🇳

   By employing the perturbative QCD (PQCD) factorization approach, we study the quasi-two-body $B_{(s)}^0\to {\eta }_c(2S){\pi }^{+}{\pi }^{-}$ decays, where the pion pair comes from the $S$-wave resonance $f_0(X)$. The Breit$-$Wigner formula for the $f_0(500)$ and $f_0(1500)$ resonances, and the Flatté model for the $f_0(980)$ resonance are adopted to parameterize the time-like scalar form factors in the two-pion distribution amplitudes. As a comparison, Bugg's model is also used for the wide $f_0(500)$ in this work. For decay rates, we found the following PQCD predictions: (a) $\mathcal{B}(B_s^0\to {\eta }_c(2S)f_0(X)[{\pi }^{+}{\pi }^{-}{]}_s)=\left(2.67_{-1.08}^{+1.78}\right)\times 10^{-5}$ when the contributions from $f_0(980)$ and $f_0(1500)$ are all taken into account; (b) $\mathcal{B}(B^0\to {\eta }_c(2S)f_0(500)[{\pi }^{+}{\pi }^{-}{]}_s)=\left(1.40_{-0.56}^{+0.92}\right)\times 10^{-6}$ in the Breit-Wigner model and $\left(1.53_{-0.61}^{+0.97}\right)\times 10^{-6}$ in the Bugg's model.

   hep-phCPC(2017)·25 citations
6. 06*

   Causal Relativistic Hydrodynamics of Conformal Fermi-Dirac Gases

   Milton Aguilar🇦🇷 · Esteban Calzetta🇦🇷

   In this paper we address the derivation of causal relativistic hydrodynamics, formulated within the framework of Divergence Type Theories (DTTs), from kinetic theory for spinless particles obeying Fermi-Dirac statistics. The approach leads to expressions for the particle current and energy momentum tensor that are formally divergent, but may be given meaning through a process of regularization and renormalization. We demonstrate the procedure through an analysis of the stability of an homogeneous anisotropic configuration. In the DTT framework, as in kinetic theory, these configurations are stable. By contrast, hydrodynamics as derived from the Grad approximation would predict that highly anisotropic configurations are unstable.

   hep-phPRD(2017)·13 citations
7. 07*

   Sumino Model and My Personal View

   Yoshio Koide🇯🇵

   There are two formulas for charged lepton mass relation: One is a formula (formula A) which was proposed based on a U(3) family model on 1982. The formula A will be satisfied only masses switched off all interactions except for U(3) family interactions. Other one (formula B) is an empirical formula which we have recognized after a report of the precise measurement of tau lepton mass, 1992. The formula B is excellently satisfied by pole masses of the charged leptons. However, this excellent agreement may be an accidental coincidence. Nevertheless, 2009, Sumino has paid attention to the formula B. He has proposed a family gauge boson model and thereby he has tried to understand why the formula B is so well satisfied with pole masses. In this talk, the following views are given: (i) What direction of flavor physics research is suggested by the formula A; (ii) How the Sumino model is misunderstood by people and what we should learn from his model; (iii) What is strategy of my recent work, U(3)$\times$U(3)${}^{\prime }$ model.

   hep-ph1 citation
8. 08*

   Future Higgs Studies: A Theorist's Outlook

   Howard E. Haber🇺🇸

   We examine some of the theoretical and phenomenological implications of the Higgs boson discovery and discuss what these imply for future Higgs studies at the LHC and future colliders. In particular, one of the outstanding unanswered questions is whether additional scalars beyond the observed Higgs boson are present in the spectrum of fundamental particles. Any theory of a non-minimal Higgs sector must possess a scalar state whose properties are approximately those of the Standard Model Higgs boson. This can be achieved in the so-called alignment limit of the extended scalar sector. Examples of scalar sectors in which an approximate alignment limit is achieved are surveyed.

   hep-phPoS(2017)·5 citations
9. 09*

   $\varphi \varphi$ and $J/\psi \varphi$ mass spectra in decay $B_s^0\to J/\psi \varphi \varphi$

   A.A. Kozhevnikov🇷🇺

   The mass spectra of the $\varphi \varphi$ and $J/\psi \varphi$ states in the decay $B_s^0\to J/\psi \varphi \varphi$ recently observed by LHCb are calculated in the model which takes into account the $J^P=0^{+},0^{-},2^{+}$ intermediate resonances $R_1$, $R_2$ in the $\varphi \varphi$ channel and the $J^P=1^{+}$ ones, $X_1$, $X_2$, in the $J/\psi \varphi$ channel. When obtaining the expressions for the effective amplitudes and mass spectra, the approximate threshold kinematics of the decay is used essentially. The $R_1-R_2$ and $X_1-X_2$ mixings arising due to the common decay modes $\varphi \varphi$ and $J/\psi \varphi$, respectively, are also taken into account. The obtained expressions for the mass spectra are applied for extracting the information about masses and coupling constants of the resonances in the $\varphi \varphi$ and $J/\psi \varphi$ final states.

   hep-phhep-exnucl-thPRD(2017)·2 citations
10. 10*

    Spin-dependent sum rules connecting real and virtual Compton scattering verified

    Vadim Lensky🇩🇪 · Vladimir Pascalutsa🇩🇪 · Marc Vanderhaeghen🇩🇪 · Chung Wen Kao🇹🇼

    We present a detailed derivation of the two sum rules relating the spin polarizabilities measured in real, virtual, and doubly-virtual Compton scattering. For example, the polarizability ${\delta }_{LT}$, accessed in inclusive electron scattering, is related to the spin polarizability ${\gamma }_{E1E1}$ and the slope of generalized polarizabilities $P^{(M1,M1)1}-P^{(L1,L1)1}$, measured in, respectively, the real and the virtual Compton scattering. We verify these sum rules in different variants of chiral perturbation theory, discuss their empirical verification for the proton, and prospect their use in studies of the nucleon spin structure.

    hep-phnucl-exnucl-thPRD(2017)·14 citations
11. 11*

    $CP$ violation induced by the double resonance for pure annihilation decay process in Perturbative QCD

    Gang Lü🇨🇳 · Ye Lu🇨🇳 · Sheng-Tao Li🇨🇳 · Yu-Ting Wang🇨🇳

    In Perturbative QCD (PQCD) approach we study the direct $CP$ violation in the pure annihilation decay process of ${\bar{B}}_s^0\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$ induced by the $\rho$ and $\omega$ double resonance effect. Generally, the $CP$ violation is small in the pure annihilation type decay process. However, we find that the $CP$ violation can be enhanced by double $\rho -\omega$ interference when the invariant masses of the ${\pi }^{+}{\pi }^{-}$ pairs are in the vicinity of the $\omega$ resonance. For the decay process of ${\bar{B}}_s^0\to {\pi }^{+}{\pi }^{-}{\pi }^{+}{\pi }^{-}$, the maximum $CP$ violation can reach 28.64{\%}.

    hep-phEPJC(2017)·9 citations
12. 12*

    Strong electroweak phase transition in a model with extended scalar sector

    Mina Saeedhoseini🇮🇷 · Ali Tofighi🇮🇷

    In this paper we consider an extension of the Standard Model(SM) with additional gauge singlets which exhibits a strong first order phase transition. Due to this first order phase transition in the early universe gravitational waves are produced. We estimate the contributions such as the sound wave, the bubble wall collision and the plasma turbulence to the stochastic gravitational wave background, and we find that the strength at the peak frequency is large enough to be detected at future gravitational interferometers such as eLISA. Deviations in the various Higgs boson self couplings are also evaluated.

    hep-phAdv.High Energy Phys.(2017)·3 citations
13. 13*

    Neutrinoless Double Beta Decay in Left-Right Symmetry with Universal Seesaw

    Frank F. Deppisch🇬🇧 · Chandan Hati🇮🇳 · Sudhanwa Patra🇮🇳 · Prativa Pritimita🇮🇳 · Utpal Sarkar🇮🇳

    We discuss a class of left-right symmetric theories with a universal seesaw mechanism for fermion masses and mixing and the implications for neutrinoless double beta ($0\nu \beta \beta$) decay where neutrino masses are governed by natural type-II seesaw dominance. The scalar sector consists of left- and right-handed Higgs doublets and triplets, while the conventional Higgs bidoublet is absent in this scenario. We use the Higgs doublets to implement the left-right and the electroweak symmetry breaking. On the other hand, the Higgs triplets with induced vacuum expectation values can give Majorana masses to light and heavy neutrinos and mediate $0\nu \beta \beta$ decay. In the absence of the Dirac mass terms for the neutrinos, this framework can naturally realize type-II seesaw dominance even if the right-handed neutrinos have masses of a few TeV. We study the implications of this framework in the context of $0\nu \beta \beta$ decay and gauge coupling unification.

    hep-phPRD(2018)·33 citations
14. 14*

    Leptophilic neutral Higgs bosons in two Higgs doublet model at a linear collider

    Majid Hashemi🇮🇷

    This paper addresses the question of observability of neutral Higgs bosons through the leptonic decay in a two Higgs doublet model (2HDM). Both scalar and pseudoscalar Higgs bosons ($H,A$) are considered. The model is set to type IV to enhance the leptonic decay. In such a scenario, a signal production process like $e^{+}{e}^{-}\to A^0{H}^0\to \tau \tau \mu \mu$ or $\mu \mu \tau \tau$ would provide a clear signal on top of the background in a di-muon invariant mass distribution far from the $Z$ boson pole mass. The analysis is based on a $\tau$-id algorithm which preselects events if they have two $\tau$ jets by requiring a hadronic $\tau$ decay. Several benchmark points are defined for the search, requiring a linear collider operating at $\sqrt{s}=$ 0.5 and 1 TeV. It is shown that the signal can be observed on top of the background in all benchmark points at an integrated luminosity of 1000 $f{b}^{-1}$.

    hep-phEPJC(2017)·8 citations
15. 15*

    Strong isospin breaking at production of light scalars

    N.N. Achasov🇷🇺 · G.N. Shestakov🇷🇺

    It is discussed breaking the isotopic symmetry as the tool of studying the mechanism production and nature of light scalar mesons.

    hep-phhep-exnucl-thNucl.Part.Phys.Proc.(2017)·9 citations
16. 16*

    Non-Minimal Coupling of the Higgs Boson to Curvature in an Inflationary Universe

    Xavier Calmet🇬🇧 · Iberê Kuntz🇬🇧 · Ian G. Moss🇬🇧

    In the absence of new physics around $10^{10}$ GeV, the electroweak vacuum is at best metastable. This represents a major challenge for high scale inflationary models as, during the early rapid expansion of the universe, it seems difficult to understand how the Higgs vacuum would not decay to the true lower vacuum of the theory with catastrophic consequences if inflation took place at a scale above $10^{10}$ GeV. In this paper we show that the non-minimal coupling of the Higgs boson to curvature could solve this problem by generating a direct coupling of the Higgs boson to the inflationary potential thereby stabilizing the electroweak vacuum. For specific values of the Higgs field initial condition and of its non-minimal coupling, inflation can drive the Higgs field to the electroweak vacuum quickly during inflation.

    hep-phastro-ph.COgr-qchep-thFound.Phys.(2018)·23 citations
17. 17*

    Strong dynamics in a classically scale invariant extension of the Standard Model with flatland

    Naoyuki Haba🇯🇵 · Toshifumi Yamada🇯🇵

    We investigate the scenario where the Standard Model is extended with classical scale invariance, which is broken by chiral symmetry breaking and confinement in a new strongly-coupled gauge theory that resembles QCD. The Standard Model Higgs field emerges as a result of the mixing of a scalar meson in the new strong dynamics and a massless elementary scalar field. The mass and scalar decay constant of that scalar meson, which are generated dynamically in the new gauge theory, give rise to the Higgs field mass term, automatically possessing the correct negative sign by the bosonic seesaw mechanism. Using analogy with QCD, we evaluate the dynamical scale of the new gauge theory and further make quantitative predictions for light pseudo-Nambu-Goldstone bosons associated with axial symmetry breaking along chiral symmetry breaking in the new gauge theory. A prominent consequence of the scenario is that there should be a Standard Model gauge singlet pseudo-Nambu-Goldstone boson with mass below 220GeV, which couples to two electroweak gauge bosons through the Wess-Zumino-Witten term, whose strength is thus determined by the dynamical scale of the new gauge theory. Other pseudo-Nambu-Goldstone bosons, charged under the electroweak gauge groups, also appear. Concerning the theoretical aspects, it is shown that the scalar quartic coupling can vanish at the Planck scale with the top quark pole mass as large as 172.5GeV, realizing the flatland scenario without being in tension with the current experimental data.

    hep-phPRD(2017)·13 citations
18. 18*

    Relaxation leptogenesis, isocurvature perturbations, and the cosmic infrared background

    Masahiro Kawasaki🇯🇵 · Alexander Kusenko🇯🇵 · Lauren Pearce🇺🇸 · Louis Yang🇺🇸

    Observations of cosmic infrared background (CIB) radiation exhibit significant fluctuations on small angular scales. A number of explanations have been put forth, but there is currently no consensus on the origin of these large fluctuations. We consider the possibility that small-scale fluctuations in matter-antimatter asymmetry could lead to variations in star formation rates which are responsible for the CIB fluctuations. We show that the recently proposed Higgs relaxation leptogenesis mechanism can produce such small-scale baryonic isocurvature perturbations which can explain the observed excess in the CIB fluctuations.

    hep-phastro-ph.COPRD(2017)·11 citations
19. 19*

    Exploring Extensions of the Scalar Sector of the Standard Model

    Najimuddin Khan🇮🇳

    In this thesis, various extensions of the scalar sector have been considered comprising of different $SU(2{)}_L$ multiplets. If the extended scalar sector participates in the electroweak symmetry breaking then these extra scalars need to couple with the known standard model particles. In this work, it has been shown that the vector boson scattering involving scalar boson exchanges provide a complimentary way to direct search methods to probe into the scalar sector. As different extended scalar sectors have similar types of scalar fields, e.g., an extra $CP$-even Higgs, charged Higgs etc., these new physics models can give rise to the similar types of experimental signatures. It is possible to distinguish between such models at various vector boson scattering processes by looking at the resonances. Also, the shapes of the resonances can provide further insight to the relevant parameter space of these models. As in the SM, the electroweak vacuum is metastable, it is important to explore if an extended scalar has an answer in its reserve. As the scalar weakly interacting massive scalar particles protected by $Z_2$ symmetry can serve as viable dark matter candidates, it is interesting to explore if they help prolong the lifetime of the Universe. The effective Higgs potential gets modified in the presence of these new extra scalars, improving the stability of electroweak vacuum. Such an exercise has been undertaken in various kinds of extended scalar sectors. In order to show the explicit dependence of the electroweak stability on different parameters of these extended sectors, various kinds of phase diagrams have been presented. Graphical demonstrations have been provided to illustrate how the confidence level, at which stability of electroweak vacuum is excluded, depends on such new physics parameters.

    hep-ph5 citations
20. 20*

    Astrophysical background and dark matter implication based on latest AMS-02 data

    Hong-Bo Jin🇨🇳 · Yue-Liang Wu🇨🇳 · Yu-Feng Zhou🇨🇳

    The cosmic ray(CR) positrons and antiprotons are often regarded as the collision products of CR nucleons with the interstellar medium. However this conclusion is challenged by recent experimental data. In this work, we choose the latest AMS-02 data to analyze the astrophysical background of CR positrons and antiprotons with the GALPROP code for CR propagation and the QGSJET-II-04 model for the hadronic interactions. The results show that in low energies the predicted fluxes of CR antiprotons and positrons are consistent with AMS-02 data in the diffusion model combining the re-acceleration and convection terms (DCR model). Thus, the excess of CR antiprotons in the low energy are not justified. In that model, the predicted flux of CR protons is consistent with AMS-02 data whose hardening feature above 330 GeV is also matched. Based on that model, the total fluxes of CR electrons and positrons from AMS-02 are also used to analyzed the interpretation of dark matter annihilation about the positron excess. The predicted best-fit masses of dark matter are from 400 GeV to 4 TeV. The DCR model does not give the unusual interpretation of the positron excess.

    hep-phApJ(2020)·24 citations
21. 21*

    From direct detection to relic abundance: the case of proton-philic spin-dependent inelastic Dark Matter

    Stefano Scopel🇰🇷 · Hyeonhye Yu (Sogang U.)🇰🇷

    We discuss strategies to make inferences on the thermal relic abundance of a Weakly Interacting Massive Particle (WIMP) when the same effective dimension-six operator that explains an experimental excess in direct detection is assumed to drive decoupling at freeze-out, and apply them to the proton-philic Spin-dependent Inelastic Dark Matter (pSIDM) scenario, a phenomenological set-up containing two states ${\chi }_1$ and ${\chi }_2$ with $m_{{\chi }_2}>m_{{\chi }_1}$ that we have shown in a previous paper to explain the DAMA effect in compliance with the constraints from other detectors. We update experimental constraints on pSIDM, extend the analysis to the most general spin-dependent momentum-dependent interactions allowed by non-relativistic Effective Field Theory (EFT), and consider for the WIMP velocity distribution in our Galaxy both a halo-independent approach and a standard Maxwellian. The problem of calculating the relic abundance by using direct detection data to fix the model parameters is affected by a strong sensitivity on $f(v)$ and by the degeneracy between the WIMP local density and the WIMP-nucleon scattering cross section. As a consequence, a DM direct detection experiment is not directly sensitive to the physical cut-off scale of the EFT, but on some dimensional combination that does not depend on the actual value of the relic abundance. However, such degeneracy can be used to develop a consistency test on the possibility that the WIMP is a thermal relic in the first place. When we apply it to the pSIDM scenario we find that only a WIMP with a standard spin-dependent interaction ${\mathcal{O}}_{spin}$ with quarks can be a thermal relic, for a galactic velocity distribution that departs from a Maxwellian. However all the ${\chi }_2$ states must have already decayed today, and this requires some additional mechanism besides that provided by the ${\mathcal{O}}_{spin}$ operator.

    hep-phastro-ph.COJCAP(2017)·6 citations
22. 22*

    Dark Matter Search in Space: Combined Analysis of Cosmic Ray Antiproton-to-Proton Flux Ratio and Positron Flux Measured by AMS-02

    Jie Feng🇨🇳 · Hong-Hao Zhang🇨🇳

    Dark matter search in space has been carried out for many years. Measurements of cosmic ray photons, charged antiparticles and neutrinos are useful tools for dark matter indirect search. The antiparticle energy spectra of cosmic rays have several exciting features such as the unexpected positron excess at energy about 10 -- 500 GeV and the remarkably flattening antiproton/proton at energy about 60--450 GeV precisely measured by the AMS-02 experiment, which can not be explained simultaneously by secondary production in interstellar medium. In this work, we report a combined analysis of cosmic ray antiproton and positron spectra arising from dark matter on the top of a secondary production in a spatial-dependent propagation model. We discuss the systematics from antiproton production cross section using the two latest Monte Carlo generators, i.e. EPOS LHC and QGSJET-II-04m, respectively. We compare their results. In the case of EPOS LHC, we find that the dark matter pair annihilating into tau leptons channel with 100% branching ratio is the only possible one channel scenario to explain data. On the other hand, there is not a single possible channel in the case of QGSJET-II-04m. We also propose possible two-channel scenarios based on these two Monte Carlo generators.

    hep-phastro-ph.COhep-exApJ(2018)·27 citations
23. 23*

    Effects of QCD Equation of State on the Stochastic Gravitational Wave Background

    Sampurn Anand🇮🇳 · Ujjal Kumar Dey🇮🇳 · Subhendra Mohanty🇮🇳

    Cosmological phase transitions can be a source of Stochastic Gravitational Wave (SGW) background. Apart from the dynamics of the phase transition, the characteristic frequency and the fractional energy density ${\Omega }_{\mathrm{gw}}$ of the SGW depends upon the temperature of the transition. In this article, we compute the SGW spectrum in the light of QCD equation of state provided by the lattice results. We find that the inclusion of trace anomaly from lattice QCD, enhances the SGW signal generated during QCD phase transition by $\sim 50\%$ and the peak frequency of the QCD era SGW are shifted higher by $\sim 25\%$ as compared to the earlier estimates without trace anomaly. This result is extremely significant for testing the phase transition dynamics near QCD epoch.

    hep-phastro-ph.COgr-qcJCAP(2017)·20 citations
24. 24*

    Trilinear-Augmented Gaugino Mediation

    Jan Heisig🇩🇪 · Jörn Kersten🇳🇴 · Nick Murphy🇩🇰 · Inga Strümke🇳🇴

    We consider a gaugino-mediated supersymmetry breaking scenario where in addition to the gauginos the Higgs fields couple directly to the field that breaks supersymmetry. This yields non-vanishing trilinear scalar couplings in general, which can lead to large mixing in the stop sector providing a sufficiently large Higgs mass. Using the most recent release of FeynHiggs, we show the implications on the parameter space. Assuming a gravitino LSP, we find allowed points with a neutralino, sneutrino or stau NLSP. We test these points against the results of Run 1 of the LHC, considering in particular searches for heavy stable charged particles.

    hep-phJHEP(2017)·5 citations
25. 25*

    Status of Dark Matter in the Universe

    Katherine Freese🇸🇪

    Over the past few decades, a consensus picture has emerged in which roughly a quarter of the universe consists of dark matter. I begin with a review of the observational evidence for the existence of dark matter: rotation curves of galaxies, gravitational lensing measurements, hot gas in clusters, galaxy formation, primordial nucleosynthesis and cosmic microwave background observations. Then I discuss a number of anomalous signals in a variety of data sets that may point to discovery, though all of them are controversial. The annual modulation in the DAMA detector and/or the gamma-ray excess seen in the Fermi Gamma Ray Space Telescope from the Galactic Center could be due to WIMPs; a 3.5 keV X-ray line from multiple sources could be due to sterile neutrinos; or the 511 keV line in INTEGRAL data could be due to MeV dark matter. All of these would require further confirmation in other experiments or data sets to be proven correct. In addition, a new line of research on dark stars is presented, which suggests that the first stars to exist in the universe were powered by dark matter heating rather than by fusion: the observational possibility of discovering dark matter in this way is discussed.

    ↳ astro-ph.COhep-phInt.J.Mod.Phys.(2017)·144 citations
26. 26*

    Chiral vortical effect generated by chiral anomaly in vortex-skyrmions

    G.E. Volovik🇫🇮

    We discuss the type of the general macroscopic parity-violating effects, when there is the current along the vortex, which is concentrated in the vortex core. We consider vortices in superfluids, which contain the Weyl points. In the vortex core the positions of the Weyl points form the skyrmion structure. We show that the mass current concentrated in such a core is provided by the spectral flow through the Weyl points according to the Adler-Bell-Jackiw equation for chiral anomaly.

    ↳ cond-mat.otherhep-phJETP Lett.(2017)·5 citations
27. 27*

    Analytical coalescence formula for particle production in relativistic heavy-ion collisions

    Kai-Jia Sun🇨🇳 · Lie-Wen Chen🇨🇳

    Based on a covariant coalescence model with a blast-wave-like parametrization for the phase-space configuration of constituent particles at freeze-out, we derive an approximate analytical formula for the yields of clusters produced in relativistic heavy-ion collisions. Compared to previous existing formulae, the present work additionally considers the contributions from the longitudinal dimension in momentum space, the relativistic corrections and the finite size effects of the produced clusters relative to the spatial distribution of constituent particles at freeze-out. The new analytical coalescence formula provides a useful tool to evaluate the yield of produced clusters, such as light nuclei from nucleon coalescence and hadrons from quark coalescence, in heavy-ion collisions. As a first application of the new analytical formula, we explore the strangeness population factor $S_3{=}_{\Lambda }^3$H/(${}^3$He$\times \Lambda /$p) based on nucleon/$\Lambda$ coalescence as well as the production of exotic hadrons based on quark coalescence, in central Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. The results are compared with the predictions from other models.

    ↳ nucl-thastro-ph.HEhep-phnucl-exPRC(2017)·60 citations
28. 28*

    Search for the QCD Critical Point with Fluctuations of Conserved Quantities in Relativistic Heavy-Ion Collisions at RHIC : An Overview

    Xiaofeng Luo🇨🇳 · Nu Xu🇺🇸

    Fluctuations of conserved quantities, such as baryon, electric charge and strangeness number, are sensitive observables in relativistic heavy-ion collisions to probe the QCD phase transition and search for the QCD critical point. In this paper, we review the experimental measurements of the cumulants (up to fourth order) of event-by-event net-proton (proxy for net-baryon), net-charge and net-kaon (proxy for net-strangeness) multiplicity distributions in Au+Au collisions at $\sqrt{s_{NN}}=7.7,11.5,14.5,19.6,27,39,62.4,200$ GeV from the first phase of beam energy scan program at the Relativistic Heavy-Ion Collider (RHIC). We also summarize the data analysis methods of suppressing the volume fluctuations, auto-correlations and the unified description of efficiency correction and error estimation. Based on theoretical and model calculations, we will discuss the characteristic signatures of critical point as well as backgrounds for the fluctuation observables in heavy-ion collisions. The physics implications and the future second phase of the beam energy scan (2019-2020) at RHIC will be also discussed.

    ↳ nucl-exhep-exhep-phnucl-thNucl.Sci.Tech.(2017)·553 citations
29. 29*

    Temperature dependence of shear viscosity of $SU(3)$--gluodynamics within lattice simulation

    Nikita Astrakhantsev🇷🇺 · Viktor Braguta🇷🇺 · Andrey Kotov🇷🇺

    In this paper we study the shear viscosity temperature dependence of $SU(3)$--gluodynamics within lattice simulation. To do so, we measure the correlation functions of energy-momentum tensor in the range of temperatures $T/T_c\in [0.9,1.5]$. To extract the values of shear viscosity we used two approaches. The first one is to fit the lattice data with some physically motivated ansatz for the spectral function with unknown parameters and then determine shear viscosity. The second approach is to apply the Backus-Gilbert method which allows to extract shear viscosity from the lattice data nonparametrically. The results obtained within both approaches agree with each other. Our results allow us to conclude that within the temperature range $T/T_c\in [0.9,1.5]$ SU(3)--gluodynamics reveals the properties of a strongly interacting system, which cannot be described perturbatively, and has the ratio $\eta /s$ close to the value $1/4\pi$ in $N=4$ Supersymmetric Yang-Mills theory.

    ↳ hep-lathep-phhep-thnucl-thJHEP(2017)·108 citations
30. 30*

    Some Clarifications on the Duration of Inflation in Loop Quantum Cosmology

    Boris Bolliet🇫🇷 · Aurélien Barrau🇫🇷 · Killian Martineau🇫🇷 · Flora Moulin🇫🇷

    The prediction of a phase of inflation whose number of e-folds is constrained is an important feature of loop quantum cosmology. This work aims at giving some elementary clarifications on the role of the different hypotheses leading to this conclusion. We show that the duration of inflation does not depend significantly on the modified background dynamics in the quantum regime.

    ↳ gr-qcastro-ph.COhep-phClass.Quant.Grav.(2017)·30 citations
31. 31*

    Studies of dark sector & B decays involving $\tau$ at Belle and Belle II

    Gianluca Inguglia🇩🇪

    The Belle II experiment aims to record 50 ab${}^{-1}$ data with the high luminosity to be provided by the SuperKEKB asymmetric-energy electron-positron collider. The anticipated high statistics data enables us to perform studies of $B$ decays involving $\tau$ leptons such as $B^{+}\to {\tau }^{+}{\nu }_{\tau }$ and $B\to D^{(\ast )}{\tau }^{+}{\nu }_{\tau }$ modes. The precise measurements of branching fraction and of the $\tau$ lepton polarization in these $B$ decays provide a very sensitive indirect search for a charged Higgs boson. Belle II sensitivity for the charged Higgs is complementary to direct searches at ATLAS and CMS. With the large data sample and by using dedicated triggers the Belle II experiment is expected to explore dark sector by searching for visible and invisible decays of the dark photon and the dark Higgs boson, and by also searching for low mass dark matter with unprecedented precision.

    ↳ hep-exhep-phPoS(2016)·4 citations
32. 32*

    Alien Calculus and non perturbative effects in Quantum Field Theory

    Marc P. Bellon🇫🇷

    In many domains of physics, methods are needed to deal with non-perturbative aspects. I want here to argue that a good approach is to work on the Borel transforms of the quantities of interest, the singularities of which give non-perturbative contributions. These singularities in many cases can be largely determined by using the alien calculus developed by Jean Écalle. My main example will be the two point function of a massless theory given as a solution of a renormalization group equation.

    ↳ hep-thhep-phFront.Phys.(Beijing)(2016)·4 citations
33. 33*

    Volkov States and Non-linear Compton Scattering in Short and Intense Laser Pulses

    Daniel Seipt🇬🇧

    The collision of ultra-relativistic electron beams with intense short laser pulses makes possible to study QED in the high-intensity regime. Present day high-intensity lasers mostly operate with short pulse durations of several tens of femtoseconds, i.e. only a few optical cycles. A profound theoretical understanding of short pulse effects is important not only for studying fundamental aspects of high-intensity laser matter interaction, but also for applications as novel X- and gamma-ray radiation sources. In this article we give a brief overview of the theory of high-intensity QED with focus on effects due to the short pulse duration. The non-linear spectral broadening in non-linear Compton scattering due to the short pulse duration and its compensation is discussed.

    ↳ physics.plasm-phhep-ph49 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.