Mon·Dec 19, 2016Monday·December 19, 2016

1. 01*

   Light charged Higgs boson scenario in 3HDMs

   A. G. Akeroyd🇬🇧 · Stefano Moretti🇬🇧 · Kei Yagyu🇮🇹 · Emine Yildirim🇬🇧

   The measurement of the $B\to X_s\gamma$ process gives important constraints on physics related to charged Higgs bosons ($H^{\pm }$). In 2-Higgs Doublet Models (2HDMs) with a softly-broken $Z_2$ symmetry, a light $H^{\pm }$ scenario, in which $H^{\pm }$ can be produced via the top decay, is possible in two of four types of Yukawa interactions (the so-called Type-I and Type-X). In these types of 2HDMs, the $H^{\pm }\to {\tau }^{\pm }\nu$ decay mode is dominant in wide regions of the parameter space. In this report, we discuss the other possibility of a light charged Higgs boson scenario in 3-Higgs-Doublet Models (3HDMs) based on the results obtained in Ref. [1]. We show that charged Higgs bosons can mainly decay into $cb$ without contradiction with the $B\to X_s\gamma$ data and the direct searches for charged Higgs bosons at the LHC, and this scenario cannot be realized in the 2HDMs.

   hep-phPoS(2016)·3 citations
2. 02*

   Likelihood Analysis of the Minimal AMSB Model

   E. Bagnaschi🇩🇪 · M. Borsato🇪🇸 · K. Sakurai🇬🇧 · O. Buchmueller🇬🇧 · R. Cavanaugh🇺🇸 · V. Chobanova🇪🇸 · M. Citron🇬🇧 · J.C. Costa🇬🇧 · A. De Roeck🇨🇭 · M.J. Dolan🇦🇺 · J.R. Ellis🇬🇧 · H. Flächer🇬🇧 and 8 other authors

   We perform a likelihood analysis of the minimal Anomaly-Mediated Supersymmetry Breaking (mAMSB) model using constraints from cosmology and accelerator experiments. We find that a wino-like or a Higgsino-like neutralino LSP, $m_{{\tilde{\chi }}_1^0}$, may provide the cold dark matter (DM) with similar likelihood. The upper limit on the DM density from Planck and other experiments enforces $m_{{\tilde{\chi }}_1^0}\lesssim 3TeV$ after the inclusion of Sommerfeld enhancement in its annihilations. If most of the cold DM density is provided by the ${\tilde{\chi }}_0^1$, the measured value of the Higgs mass favours a limited range of $\tan \beta \sim 5$ (or for $\mu >0$, $\tan \beta \sim 45$) but the scalar mass $m_0$ is poorly constrained. In the wino-LSP case, $m_{3/2}$ is constrained to about $900TeV$ and $m_{{\tilde{\chi }}_1^0}$ to $2.9\pm 0.1TeV$, whereas in the Higgsino-LSP case $m_{3/2}$ has just a lower limit $\gtrsim 650TeV$ ($\gtrsim 480TeV$) and $m_{{\tilde{\chi }}_1^0}$ is constrained to $1.12(1.13)\pm 0.02TeV$ in the $\mu >0$ ($\mu <0$) scenario. In neither case can the anomalous magnetic moment of the muon, $(g-2{)}_{\mu }$, be improved significantly relative to its Standard Model (SM) value, nor do flavour measurements constrain the model significantly, and there are poor prospects for discovering supersymmetric particles at the LHC, {though there} are some prospects for direct DM detection. On the other hand, if the $m_{{\tilde{\chi }}_1^0}$ contributes only a fraction of the cold DM density, {future LHC $E_T$-based searches for gluinos, squarks and heavier chargino and neutralino states as well as disappearing track searches in the wino-like LSP region will be relevant}, and interference effects enable $\mathrm{BR}(B_{s,d}\to {\mu }^{+}{\mu }^{-})$ to agree with the data better than in the SM in the case of wino-like DM with $\mu >0$.

   hep-phastro-ph.HEhep-exEPJC(2017)·45 citations
3. 03*

   FN-2HDM: Two Higgs Doublet Models with Froggatt-Nielsen Symmetry

   Avital Dery🇮🇱 · Yosef Nir🇮🇱

   We embed Two Higgs Doublet Models (2HDMs) in the Froggatt Nielsen (FN) framework. We find that the approximate FN symmetry predicts i) approximate Natural Flavor Conservation (NFC) of Types II or IV in the Yukawa sector, and ii) approximate Peccei-Quinn (PQ) symmetry in the scalar sector. We discuss the phenomenological consequences of these features.

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

   Better Higgs Measurements Through Information Geometry

   Johann Brehmer🇩🇪 · Kyle Cranmer🇺🇸 · Felix Kling🇺🇸 · Tilman Plehn🇩🇪

   Information geometry can be used to understand and optimize Higgs measurements at the LHC. The Fisher information encodes the maximum sensitivity of observables to model parameters for a given experiment. Applied to higher-dimensional operators, it defines the new physics reach of any LHC signature. We calculate the Fisher information for Higgs production in weak boson fusion with decays into tau pairs and four leptons, and for Higgs production in association with a single top quark. In a next step we analyze how the differential information is distributed over phase space, which defines optimal event selections. Conversely, we consider the information in the distribution of a subset of the kinematic variables, showing which production and decay observables are the most powerful and how much information is lost in traditional histogram-based analysis methods compared to fully multivariate ones.

   hep-phphysics.data-anPRD(2017)·77 citations
5. 05*

   Light-front holographic distribution amplitudes of pseudoscalar mesons and their application to $B$-meson decays

   Qin Chang🇨🇳 · Stanley J. Brodsky🇺🇸 · Xin-Qiang Li🇨🇳

   In this paper the dynamical spin effects of the light-front holographic wavefunctions for light pseudoscalar mesons are studied using two different assumptions. These improved wavefunctions are then confronted with a number of sensitive hadronic observables: the decay constants of $\pi$ and $K$ mesons, their $\xi$-moments, the pion-to-photon transition form factor, and the pure annihilation ${\bar{B}}_s\to {\pi }^{+}{\pi }^{-}$ and ${\bar{B}}_d\to K^{+}{K}^{-}$ decays. Taking $f_{\pi }$, $f_K$ and their ratio $f_K/f_{\pi }$ as constraint conditions, the ${\chi }^2$ analyses for holographic parameters, including the mass scale parameter $\sqrt{\lambda }$ and effective quark masses, are all consistent with the mass scale which controls the slopes of the light-quark hadronic Regge trajectories. In addition, we also show how the improved light-front holographic distribution amplitudes regulate the end-point divergences which appear in the annihilation amplitudes of $B\to PP$ decays.

   hep-phhep-exPRD(2017)·29 citations
6. 06*

   Modeling Charmonium-$\eta$ Decays of $J^{PC}=1^{--}$ Higher Charmonia

   Muhammad Naeem Anwar🇨🇳 · Yu Lu🇨🇳 · Bing-Song Zou🇨🇳

   We propose a new model to create a light meson in the heavy quarkonium transition, which is inspired by the Nambu$-$Jona-Lasinio (NJL) model. Hadronic transitions of $J^{PC}=1^{--}$ higher charmonia with the emission of an $\eta$ meson are studied in the framework of the proposed model. The model shows its potential to reproduce the observed decay widths and make predictions for the unobserved channels. We present our predictions for the decay width of $\Psi \to J/\psi \eta$ and $\Psi \to h_c(1P)\eta$, where $\Psi$ are higher $S$ and $D$ wave vector charmonia, which provide useful references to search for higher charmonia and determine their properties in forthcoming experiments. The predicted branching fraction $\mathcal{B}(\psi (4415)\to h_c(1P)\eta )=4.62\times 10^{-4}$ is one order of magnitude smaller than the $J/\psi \eta$ channel. Estimates of partial decay width $\Gamma (Y\to J/\psi \eta )$ are given for $Y(4360)$, $Y(4390)$ and $Y(4660)$ by assuming them as $c\bar{c}$ bound states with quantum numbers $3^3{D}_1$, $3^3{D}_1$ and $5^3{S}_1$, respectively. Our results are in favor of these assignments for $Y(4360)$ and $Y(4660)$. The corresponding experimental data for these $Y$ states has large statistical errors which do not provide any constraint on the mixing angle if we introduce $S-D$ mixing. To identify $Y(4390)$, precise measurements on its hadronic branching fraction are required which are eagerly awaited from BESIII.

   hep-phhep-exnucl-thPRD(2017)·30 citations
7. 07*

   Stimulated Emission of Dark Matter Axion from Condensed Matter Excitations

   Naoto Yokoi🇯🇵 · Eiji Saitoh🇯🇵

   We discuss a possible principle for detecting dark matter axions in galactic halos. If axions constitute a condensate in the Milky Way, stimulated emissions of the axions from a type of excitation in condensed matter can be detectable. We provide general mechanism for the dark matter emission, and, as a concrete example, an emission of dark matter axions from magnetic vortex strings in a type II superconductor are investigated along with possible experimental signatures.

   hep-phastro-ph.COcond-mat.mes-hallhep-thJHEP(2018)·3 citations
8. 08*

   Stability of Azimuthal-angle Observables under Higher Order Corrections in Inclusive Three-jet Production

   F. Caporale🇪🇸 · F. G. Celiberto🇮🇹 · G. Chachamis🇪🇸 · D. Gordo Gomez🇪🇸 · A. Sabio Vera🇪🇸

   Recently, a new family of observables consisting of azimuthal-angle generalised ratios was proposed in a kinematical setup that resembles the usual Mueller-Navelet jets but with an additional tagged jet in the central region of rapidity. Non-tagged minijet activity between the three jets can affect significantly the azimuthal angle orientation of the jets and is accounted for by the introduction of two BFKL gluon Green functions. Here, we calculate the, presumably, most relevant higher order corrections to the observables by now convoluting the three leading-order jet vertices with two gluon Green functions at next-to-leading logarithmic approximation. The corrections appear to be mostly moderate giving us confidence that the recently proposed observables are actually an excellent way to probe the BFKL dynamics at the LHC. Furthermore, we allow for the jets to take values in different rapidity bins in various configurations such that a comparison between our predictions and the experimental data is a straightforward task.

   hep-phPRD(2017)·79 citations
9. 09*

   Does a band structure affect sphaleron processes?

   Koichi Funakubo🇯🇵 · Kaori Fuyuto🇺🇸 · Eibun Senaha🇹🇼

   Inspired by a recent work of Tye and Wong, we examine an effect of a band structure on baryon number preservation criteria requisite for successful electroweak baryogenesis. Action of a reduced model is fully constructed including a time component of the gauge field that is missing in the original work. The band structure is estimated more precisely in wider energy range based on WKB framework with three connection formulas to find that the band structure has little effect on the criteria at around 100 GeV temperature. We also address an issue of suppression factors peculiar to the $(B+L)$-changing process in high-energy collisions at zero temperature.

   hep-phhep-th15 citations
10. 10*

    Beyond Volkov: Solving the Second-Order Klein-Gordon Equation

    B. King🇬🇧

    Whether monochromatic, pulsed, or even constant and crossed, the field used to describe the interaction of charged fermions with an intense laser beam is mainly assumed to be of plane-wave form. We consider a simple extension to plane-wave fields and consider a scalar particle in a non-lightlike, univariate and transverse propagating electromagnetic wave. The existence of some known exact solutions in this case allows us to analyse various proposed approximations in the literature as well as the plane wave model. The results also describe some of the quantum dynamics of a scalar particle in a standing wave background.

    hep-phphysics.plasm-ph1 citation
11. 11*

    Probability Densities of the effective neutrino masses $m_{\beta }$ and $m_{\beta \beta }$

    Andrea Di Iura🇮🇹 · Davide Meloni🇮🇹

    We compute the probability densities of the effective neutrino masses $m_{\beta }$ and $m_{\beta \beta }$ using the Kernel Density Estimate (KDE) approach applied to a distribution of points in the $(m_{\min },m_{\beta \beta })$ and $(m_{\beta },m_{\beta \beta })$ planes, obtained using the available Probability Distribution Functions (PDFs) of the neutrino mixing and mass differences, with the additional constraints coming from cosmological data on the sum of the neutrino masses. We show that the reconstructed probability densities strongly depend on the assumed set of cosmological data: for ${\sum }_j{m}_j\le 0.68@95\%\mathrm{CL}$ a sensitive portion of the allowed values are already excluded by null results of experiments searching for $m_{\beta \beta }$ and $m_{\beta }$, whereas in the case ${\sum }_j{m}_j\le 0.23@95\%\mathrm{CL}$ the bulk of the probability densities are below the current bounds.

    hep-phNPB(2017)·5 citations
12. 12*

    $\eta$-${\eta }^{\prime }$ Mixing in Large-$N_c$ Chiral Perturbation Theory

    P. Bickert🇩🇪 · P. Masjuan🇩🇪 · S. Scherer🇩🇪

    We present a calculation of the $\eta$-${\eta }^{\prime }$ mixing in the framework of large-$N_c$ chiral perturbation theory. A general expression for the $\eta$-${\eta }^{\prime }$ mixing at next-to-next-to-leading order (NNLO) is derived, including higher-derivative terms up to fourth order in the four momentum, kinetic and mass terms. In addition, the axial-vector decay constants of the $\eta$-${\eta }^{\prime }$ system are determined at NNLO. The numerical analysis of the results is performed successively at LO, NLO, and NNLO. We investigate the influence of one-loop corrections, OZI-rule-violating parameters, and $\mathcal{O}(N_c{p}^6)$ contact terms.

    hep-phhep-latnucl-thPRD(2017)·37 citations
13. 13*

    Event-by-event picture for the medium-induced jet evolution

    Miguel A. Escobedo🇫🇮 · Edmond Iancu🇫🇷

    We discuss the evolution of an energetic jet which propagates through a dense quark-gluon plasma and radiates gluons due to its interactions with the medium. Within perturbative QCD, this evolution can be described as a stochastic branching process, that we have managed to solve exactly. We present exact, analytic, results for the gluon spectrum (the average gluon distribution) and for the higher n-point functions, which describe correlations and fluctuations. Using these results, we construct the event-by-event picture of the gluon distribution produced via medium-induced gluon branching. In contrast to what happens in a usual QCD cascade in vacuum, the medium-induced branchings are quasi-democratic, with offspring gluons carrying sizable fractions of the energy of their parent parton. We find large fluctuations in the energy loss and in the multiplicity of soft gluons. The multiplicity distribution is predicted to exhibit KNO (Koba-Nielsen-Olesen) scaling. These predictions can be tested in Pb+Pb collisions at the LHC, via event-by-event measurements of the di-jet asymmetry. Based on JHEP 1605 (2016) 008 and arXiv:1609.06104

    hep-phnucl-thEPJ Web Conf.(2017)·0 citations
14. 14*

    Flaxion: a minimal extension to solve puzzles in the standard model

    Yohei Ema🇯🇵 · Koichi Hamaguchi🇯🇵 · Takeo Moroi🇯🇵 · Kazunori Nakayama🇯🇵

    We propose a minimal extension of the standard model which includes only one additional complex scalar field, flavon, with flavor-dependent global U(1) symmetry. It not only explains the hierarchical flavor structure in the quark and lepton sector (including neutrino sector), but also solves the strong CP problem by identifying the CP-odd component of the flavon as the QCD axion, which we call flaxion. Furthermore, the flaxion model solves the cosmological puzzles in the standard model, i.e., origin of dark matter, baryon asymmetry of the universe, and inflation. We show that the radial component of the flavon can play the role of inflaton without isocurvature nor domain wall problems. The dark matter abundance can be explained by the flaxion coherent oscillation, while the baryon asymmetry of the universe is generated through leptogenesis.

    hep-phJHEP(2017)·302 citations
15. 15*

    Probing Seesaw with Parity Restoration

    Goran Senjanović🇮🇹 · Vladimir Tello🇮🇹

    We present a novel way of testing the seesaw origin of neutrino mass in the context of the minimal Left-Right Symmetric Model. It is based on the connection between the leptonic interactions of the doubly charged scalars, whose presence is at the core of the seesaw mechanism, and the neutrino Dirac Yukawa couplings which govern, among other processes, the right-handed neutrino decays into left-handed charged leptons. We prove that any physical quantity depending on these couplings is a function of the hermitian part only which can significantly simplify their future experimental determination.

    hep-phhep-exPRL(2017)·45 citations
16. 16*

    Five-loop quark mass and field anomalous dimensions for a general gauge group

    Thomas Luthe🇩🇪 · Andreas Maier🇬🇧 · Peter Marquard🇩🇪 · York Schroder🇨🇱

    We present analytical five-loop results for the quark mass and quark field anomalous dimensions, for a general gauge group and in the MSbar scheme. We confirm the values known for the gauge group SU(3) from an independent calculation, and find full agreement with results available from large-Nf studies.

    hep-phJHEP(2017)·115 citations
17. 17*

    In-flight cLFV conversion: $e-\mu$, $e-\tau$ and $\mu -\tau$ in minimal extensions of the Standard Model with sterile fermions

    A. Abada🇫🇷 · V. De Romeri🇪🇸 · J. Orloff🇫🇷 · A.M. Teixeira🇫🇷

    We revisit charged lepton flavour in-flight conversions, in which a beam of electrons or muons is directed onto a fixed target, $e+N\to \mu +N$, $e+N\to \tau +N$ and $\mu +N\to \tau +N$, focusing on elastic interactions with a nucleus $N$. After a general discussion of this observable, we carry a full phenomenological analysis in the framework of minimal Standard Model extensions via sterile neutrinos, with a strong emphasis on the rôle of the increasingly more stringent constraints arising from other (low-energy) charged lepton flavour violation observables. Despite the potential interest of this observable, in particular in the light of certain upcoming facilities with the capability of very intense lepton beams, our study suggests that due to current bounds on three-body decays (${\ell }_i\to 3{\ell }_j$) and $\mu -e$ conversion in Nuclei, the expected number of conversions in such a minimal framework is dramatically reduced. An experimental observation of such a conversion would thus signal the presence of another source of flavour violation, possibly at tree-level.

    hep-phEPJC(2017)·42 citations
18. 18*

    Scheme variations of the QCD coupling and tau decays

    Diogo Boito🇧🇷 · Matthias Jamin🇪🇸 · Ramon Miravitllas🇪🇸

    The QCD coupling, ${\alpha }_s$, is not a physical observable since it depends on conventions related to the renormalization procedure. Here we discuss a redefinition of the coupling where changes of scheme are parametrised by a single parameter $C$. The new coupling is denoted ${\hat{\alpha }}_s$ and its running is scheme independent. Moreover, scheme variations become completely analogous to renormalization scale variations. We discuss how the coupling ${\hat{\alpha }}_s$ can be used in order to optimize predictions for the inclusive hadronic decays of the tau lepton. Preliminary investigations of the $C$-scheme in the presence of higher-order terms of the perturbative series are discussed here for the first time.

    hep-phNucl.Part.Phys.Proc.(2017)·5 citations
19. 19*

    Theoretical aspects of charged Lepton Flavour Violation

    Ana M. Teixeira🇫🇷

    If observed, charged lepton flavour violation is a clear sign of new physics - beyond the Standard Model minimally extended to accommodate neutrino oscillation data. We briefly review several extensions of the Standard Model which could potentially give rise to observable signals, also emphasising the rôle of charged lepton flavour violation in probing such new physics models.

    hep-phJ.Phys.Conf.Ser.(2017)·8 citations
20. 20*

    Triple parton scatterings in high-energy proton-proton collisions

    David d'Enterria🇨🇭 · Alexander M. Snigirev🇷🇺

    A generic expression to compute triple parton scattering (TPS) cross sections in high-energy proton-proton (pp) collisions is presented as a function of the corresponding single-parton cross sections and the transverse parton distribution in the proton encoded in an effective parameter ${\sigma }_{\mathrm{eff},\mathrm{TPS}}$. The value of ${\sigma }_{\mathrm{eff},\mathrm{TPS}}$ is closely related to the similar effective cross section that characterizes double-parton scatterings, and amounts to ${\sigma }_{\mathrm{eff},\mathrm{TPS}}=12.5\pm 4.5$ mb. Estimates for triple charm ($\mathrm{c}\overline{\mathrm{c}}$) and bottom ($\mathrm{b}\overline{\mathrm{b}}$) production in pp collisions at LHC and FCC energies are presented based on next-to-next-to-leading order perturbative calculations for single $\mathrm{c}\overline{\mathrm{c}},\mathrm{b}\overline{\mathrm{b}}$ cross sections. At $\sqrt{s}\approx$ 100 TeV, about 15% of the pp collisions produce three $\mathrm{c}\overline{\mathrm{c}}$ pairs from three different parton-parton scatterings.

    hep-phhep-exnucl-exnucl-thPRL(2017)·80 citations
21. 21*

    Model-independent determination of the two-photon exchange contribution to hyperfine splitting in muonic hydrogen

    Clara Peset🇪🇸 · Antonio Pineda🇪🇸

    We obtain a model-independent prediction for the two-photon exchange contribution to the hyperfine splitting in muonic hydrogen. We use the relation of the Wilson coefficients of the spin-dependent dimension-six four-fermion operator of NRQED applied to the electron-proton and to the muon-proton sectors. Their difference can be reliably computed using chiral perturbation theory, whereas the Wilson coefficient of the electron-proton sector can be determined from the hyperfine splitting in hydrogen. This allows us to give a precise model-independent determination of the Wilson coefficient for the muon-proton sector, and consequently of the two-photon exchange contribution to the hyperfine splitting in muonic hydrogen, which reads $\delta {\bar{E}}_{p\mu ,\mathrm{HF}}^{\mathrm{TPE}}(nS)=-\frac{1}{n^3}1.161(20)$ meV. Together with the associated QED analysis, we obtain a prediction for the hyperfine splitting in muonic hydrogen that reads $E_{p\mu ,\mathrm{HF}}^{\mathrm{th}}(1S)=182.623(27)$ meV and $E_{p\mu ,\mathrm{HF}}^{\mathrm{th}}(2S)=22.8123(33)$ meV. The error is dominated by the two-photon exchange contribution.

    ↳ nucl-thhep-phphysics.atom-phJHEP(2017)·35 citations
22. 22*

    Disorder in the Sachdev-Yee-Kitaev Model

    Yizhuang Liu🇺🇸 · Maciej A. Nowak🇵🇱 · Ismail Zahed🇺🇸

    We give qualitative arguments for the mesoscopic nature of the Sachdev-Yee-Kitaev (SYK) model in the holographic regime with $q^2/N\ll 1$ with $N$ Majorana particles coupled by antisymmetric and random interactions of range $q$. Using a stochastic deformation of the SYK model, we show that its characteristic determinant obeys a viscid Burgers equation with a small spectral viscosity in the opposite regime with $q/N=1/2$, in leading order. The stochastic evolution of the SYK model can be mapped onto that of random matrix theory, with universal Airy oscillations at the edges. A spectral hydrodynamical estimate for the relaxation of the collective modes is made.

    ↳ hep-thhep-phPLB(2017)·44 citations
23. 23*

    The next non-Gaussianity frontier: what can a measurement with $\sigma (f_{\mathrm{NL}})\lesssim 1$ tell us about multifield inflation?

    Roland de Putter🇺🇸 · Jérôme Gleyzes🇺🇸 · Olivier Doré🇺🇸

    Future galaxy surveys promise to probe local primordial non-Gaussianity at unprecedented precision, $\sigma (f_{\mathrm{NL}})\lesssim 1$. We study the implications for multifield inflation by considering spectator models, where inflation is driven by the inflaton field, but the primordial perturbations are (partially) generated by a second, spectator field. We perform an MCMC likelihood analysis using Planck data to study quantitative predictions for $f_{\mathrm{NL}}$ and other observables for a range of such spectator models. We show that models where the primordial perturbations are dominated by the spectator field, while fine-tuned within the broader parameter space, typically predict $f_{\mathrm{NL}}$ of order unity. Therefore, upcoming galaxy clustering measurements will constitute a stringent test of whether or not the generation of primordial perturbations and the accelerated expansion in the inflationary universe are due to separate phenomena.

    ↳ astro-ph.COhep-phhep-thPRD(2017)·48 citations
24. 24*

    Inflationary theory and pulsar timing investigations of primordial black holes and gravitational waves

    Nicholas Orlofsky🇺🇸 · Aaron Pierce🇺🇸 · James D. Wells🇺🇸

    The gravitational waves measured at LIGO are presumed here to come from merging primordial black holes. We ask how these primordial black holes could arise through inflationary models while not conflicting with current experiments. Among the approaches that work, we investigate the opportunity for corroboration through experimental probes of gravitational waves at pulsar timing arrays. We provide examples of theories that are already ruled out, theories that will soon be probed, and theories that will not be tested in the foreseeable future. The models that are most strongly constrained are those with a relatively broad primordial power spectrum.

    ↳ astro-ph.COhep-phPRD(2017)·104 citations
25. 25*

    Dark energy constraints from ESPRESSO tests of the stability of fundamental couplings

    A. C. O. Leite🇵🇹 · C. J. A. P. Martins🇵🇹 · P. Molaro🇮🇹 · D. Corre🇫🇷 · S. Cristiani🇮🇹

    ESPRESSO is a high-resolution-ultra-stable spectrograph for the VLT, whose commissioning will start in 2017. One of its key science goals is to test the stability of nature's fundamental couplings with unprecedented accuracy and control of possible systematics. A total of 27 nights of the ESPRESSO Consortium's guaranteed time observations (GTO) will be spent in testing the stability of the fine-structure constant and other fundamental couplings. A set of 14 priority optimal targets have been selected for the GTO period. Here we briefly discuss the criteria underlying this selection and describe the selected targets, and then present detailed forecasts of the impact of these measurements on fundamental physics and cosmology, focusing on dark energy constraints and using future supernova type Ia surveys as a comparison point. We show how canonical reconstructions of the dark energy equation of state are improved by the extended redshift range enabled by these spectroscopic measurements, and also quantify additional improvements foreseen for a future ELT-HIRES instrument.

    ↳ astro-ph.COastro-ph.IMgr-qchep-ph+1PRD(2016)·17 citations
26. 26*

    Polarization of gamma-ray burst afterglows in the synchrotron self-Compton process from a highly relativistic jet

    Hai-Nan Lin🇨🇳 · Xin Li🇨🇳 · Zhe Chang🇨🇳

    Linear polarization have been observed in both the prompt phase and afterglow of some bright gamma-ray bursts (GRBs). Polarization in the prompt phase spans a wide range, and may be as high as $\gtrsim 50\%$. In the afterglow phase, however, it is usually below $10\%$. According to the standard fireball model, GRBs are produced by synchrotron radiation and Compton scattering process in a highly relativistic jet ejected from the central engine. It is widely accepted that prompt emissions occur in the internal shock when shells with different velocities collide with each other, and the magnetic field advected by the jet from the central engine can be ordered in large scale. On the other hand, afterglows are often assumed to occur in the external shock when the jet collides with interstellar medium, and the magnetic field produced by the shock through, e.g. Weibel instability, is possibly random. In this paper, we calculate the polarization properties of the synchrotron self-Compton process from a highly relativistic jet, in which the magnetic field is randomly distributed in the shock plane. We also consider the generalized situation where a uniform magnetic component perpendicular to the shock plane is superposed on the random magnetic component. We show that, the polarization is hardly to be larger than $10\%$ if the seed electrons are isotropic in the jet frame. This may account for the observed upper limit of polarization in the afterglow phase of GRBs. In addition, if the random and uniform magnetic components decay with time in different speeds, then the polarization angle may change $90^{\circ }$ duration the temporal evolution.

    ↳ astro-ph.HEhep-phCPC(2017)·3 citations
27. 27*

    First estimation of the fission dynamics of the spectator created in heavy-ion collisions

    K. Mazurek🇵🇱 · A. Szczurek🇵🇱 · P.N. Nadtochy🇷🇺

    In peripheral high-energy heavy-ion collisions only parts of colliding nuclei interact leading to the production of a fireball. The remnants of such nuclei are called spectators. We estimated the excitation energy as a function of impact parameter. Their excitation energy is of the order of 100 MeV. The dynamical evolution of hot nuclei is described by solving a set of Langevin equations in four-dimensional collective coordinate space. The range of nuclear masses and excitation energies suits very well to ability of our model. Thus for the first time we investigate dynamically the fission and evaporation channels in de-excitation of the spectators produced in heavy-ions collision.

    ↳ nucl-thhep-phActa Phys.Polon.Supp.(2017)·1 citation
28. 28*

    Electromagnetic radiation and collectivity in small quark-gluon droplets

    Chun Shen🇺🇸 · Jean-Francois Paquet🇺🇸 · Gabriel S. Denicol🇧🇷 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    We study the multiplicity and rapidity dependence of thermal and prompt photon production in p+Pb collisions at 5.02 TeV, using a (3+1)D viscous hydrodynamic framework. Direct photon anisotropic flow coefficients $v_{2,3}^{\gamma }$ and nuclear modification factor $R_{\mathrm{pPb}}^{\gamma }(p_T)$ are presented in both the p-going (backward) and the Pb-going (forward) directions. The interplay between initial state cold nuclear effect and final state thermal enhancement at different rapidity regions is discussed. The proposed rapidity dependent thermal photon enhancement and direct photon anisotropic flow observables can elucidate non-trivial longitudinal dynamics of hot quark-gluon plasma droplets created in small collision systems.

    ↳ nucl-thhep-phnucl-exNucl.Part.Phys.Proc.(2017)·5 citations
29. 29*

    Bulk viscous corrections to photon production in the quark-gluon plasma

    Sigtryggur Hauksson🇨🇦 · Chun Shen🇺🇸 · Sangyong Jeon🇨🇦 · Charles Gale🇨🇦

    Photons radiated in heavy-ion collisions are a penetrating probe, and as such can play an important role in the determination of the quark-gluon plasma (QGP) transport coefficients. In this work we calculate the bulk viscous correction to photon production in two-to-two scattering reactions. Phase-space integrals describing the bulk viscous correction are evaluated explicitly in order to avoid the forward scattering approximation which is shown to be poor for photons at lower energies. We furthermore present hydrodynamical simulations of AA collisions focusing on the effect of this calculation on photonic observables. Bulk corrections are shown to reduce the elliptic flow of photons at higher $p_T$.

    ↳ nucl-thhep-phnucl-exNucl.Part.Phys.Proc.(2017)·7 citations
30. 30*

    Studies of three-particle correlations and reaction-plane correlators from STAR

    Prithwish Tribedy (for the STAR Collaboration)🇺🇸

    We present STAR measurements of various harmonics of three-particle correlations in $\sqrt{s_{NN}}=200$ GeV Au+Au collisions at RHIC. The quantity $⟨\cos (m{\varphi }_1+n{\varphi }_2-(m+n){\varphi }_3)⟩$ is measured for inclusive charged particles for different harmonics $m$ and $n$ as a function of collision centrality, transverse momentum $p_T$ and relative pseudorapidity $\Delta \eta$. These observables provide detailed information on global event properties like correlations between event planes of different harmonics and are particularly sensitive to the expansion dynamics of the matter produced in the collisions. We compare our measurements to different viscous hydrodynamic models. We argue that these measurements probe the three-dimensional structure of the initial state and provide unique ways to constrain the transport parameters involved in hydrodynamic modeling of heavy-ion collisions.

    ↳ nucl-exhep-phnucl-thEPJ Web Conf.(2017)·0 citations
31. 31*

    Systematic procedure for analyzing cumulants at any order

    Philippe Di Francesco🇫🇷 · Maxime Guilbaud🇺🇸 · Matthew Luzum🇧🇷 · Jean-Yves Ollitrault🇫🇷

    We present a systematic procedure for analyzing cumulants to arbitrary order in the context of heavy-ion collisions. It generalizes and improves existing procedures in many respects. In particular, particles which are correlated are allowed to belong to different phase-space windows, which may overlap. It also allows for the analysis of cumulants at any order, using a simple algorithm rather than complicated expressions to be derived and coded by hand. In the case of azimuthal correlations, it automatically corrects to leading order for detector non-uniformity, and it is useful for numerous other applications as well. We discuss several of these applications: anisotropic flow, event-plane correlations, symmetric cumulants, net baryon and net charge fluctuations.

    ↳ nucl-thhep-exhep-phnucl-exPRC(2017)·55 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.