Mon·Oct 10, 2016Monday·October 10, 2016

1. 01*

   Baryogenesis and Dark Matter in $U(1)$ Extensions

   Wan-Zhe Feng🇺🇸 · Pran Nath🇺🇸

   A brief review is given of some recent works where baryogenesis and dark matter have a common origin within the $U(1)$ extensions of the standard model and of the minimal supersymmetric standard model. The models considered generate the desired baryon asymmetry and the dark matter to baryon ratio. In one model all of the fundamental interactions do not violate lepton number, and the total $B-L$ in the Universe vanishes. In addition, one may also generate a normal hierarchy of neutrino masses and mixings in conformity with the current data. Specifically one can accommodate ${\theta }_{13}\sim 9^{\circ }$ consistent with the data from Daya Bay reactor neutrino experiment.

   hep-phMod.Phys.Lett.A(2017)·6 citations
2. 02*

   Phenomenology of relaxion-Higgs mixing

   Thomas Flacke🇰🇷 · Claudia Frugiuele🇮🇱 · Elina Fuchs🇮🇱 · Rick S. Gupta🇮🇱 · Gilad Perez🇮🇱

   We show that the relaxion generically stops its rolling at a point that breaks CP leading to relaxion-Higgs mixing. This opens the door to a variety of observational probes since the possible relaxion mass spans a broad range from sub-eV to the GeV scale. We derive constraints from current experiments (fifth force, astrophysical and cosmological probes, beam dump, flavour, LEP and LHC) and present projections from future experiments such as NA62, SHiP and PIXIE. We find that a large region of the parameter space is already under the experimental scrutiny. All the experimental constraints we derive are equally applicable for general Higgs portal models. In addition, we show that simple multiaxion (clockwork) UV completions suffer from a mild fine tuning problem, which increases with the number of sites. These results favour a cut-off scale lower than the existing theoretical bounds.

   hep-phJHEP(2017)·213 citations
3. 03*

   The Asymptotic Form of Non-Global Logarithms, Black Disc Saturation, and Gluonic Deserts

   Duff Neill🇺🇸

   We develop an asymptotic perturbation theory for the large logarithmic behavior of the non-linear integro-differential equation describing the soft correlations of QCD jet measurements, the Banfi-Marchesini-Smye (BMS) equation. This equation captures the late-time evolution of radiating color dipoles after a hard collision. This allows us to prove that at large values of the control variable (the non-global logarithm, a function of the infra-red energy scales associated with distinct hard jets in an event), the distribution has a gaussian tail. We compute the decay width analytically, giving a closed form expression, and find it to be jet geometry independent, up to the number of legs of the dipole in the active jet. Enabling the asymptotic expansion is the correct perturbative seed, where we perturb around an anzats encoding formally no real emissions, an intuition motivated by the buffer region found in jet dynamics. This must be supplemented with the correct application of the BFKL approximation to the BMS equation in collinear limits. Comparing to the asymptotics of the conformally related evolution equation encountered in small-x physics, the Balitisky-Kovchegov (BK) equation, we find that the asymptotic form of the non-global logarithms directly maps to the black-disc unitarity limit of the BK equation, despite the contrasting physical pictures. Indeed, we recover the equations of saturation physics in the final state dynamics of QCD.

   hep-phnucl-thJHEP(2017)·28 citations
4. 04*

   Effective field theory approach to open heavy flavor production in heavy-ion collisions

   Zhong-Bo Kang🇺🇸 · Felix Ringer🇺🇸 · Ivan Vitev🇺🇸

   We develop a version of Soft Collinear Effective Theory (SCET) which includes finite quark masses, as well as Glauber gluons that describe the interaction of collinear partons with QCD matter. In the framework of this new effective field theory, labeled SCET${}_{\mathrm{M},\mathrm{G}}$, we derive the massive splitting functions in the vacuum and the QCD medium for the processes $Q\to Qg$, $Q\to gQ$ and $g\to Q\bar{Q}$. The numerical effects due to finite quark masses are sizable and our results are consistent with the traditional approach to parton energy loss in the soft gluon emission limit. In addition, we present a new framework for including the medium-induced full splitting functions consistent with next-to-leading order calculations in QCD for inclusive hadron production. Finally, we show numerical results for the suppression of $D$- and $B$-mesons in heavy ion collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV and 2.76 TeV and compare to available data from the LHC.

   hep-phhep-exnucl-exnucl-thJHEP(2017)·114 citations
5. 05*

   New Physics in the Visible Final States of $B\to D^{(\ast )}\tau \nu$

   Zoltan Ligeti🇺🇸 · Michele Papucci🇺🇸 · Dean J. Robinson🇺🇸

   We derive compact expressions for the helicity amplitudes of the many-body $B\to D^{(\ast )}(\to DY)\tau (\to X\nu )\nu$ decays, specifically for $X=\ell \nu$ or $\pi$ and $Y=\pi$ or $\gamma$. We include contributions from all ten possible new physics four-Fermi operators with arbitrary couplings. Our results capture interference effects in the full phase space of the visible $\tau$ and $D^{\ast }$ decay products which are missed in analyses that treat the $\tau$ or $D^{\ast }$ or both as stable. The $\tau$ interference effects are sizable, formally of order $m_{\tau }/m_B$ for the standard model, and may be of order unity in the presence of new physics. Treating interference correctly is essential when considering kinematic distributions of the $\tau$ or $D^{\ast }$ decay products, and when including experimentally unavoidable phase space cuts. Our amplitude-level results also allow for efficient exploration of new physics effects in the fully differential phase space, by enabling experiments to perform such studies on fully simulated Monte Carlo datasets via efficient event reweighing. As an example, we explore a class of new physics interactions that can fit the observed $R(D^{(\ast )})$ ratios, and show that analyses including more differential kinematic information can provide greater discriminating power for new physics, than single kinematic variables alone.

   hep-phhep-exJHEP(2017)·93 citations
6. 06*

   Investigation of the light four-quark states with exotic $J^{PC}=0^{--}$

   Zhuo-Ran Huang🇨🇳 · Wei Chen🇨🇦 · T. G. Steele🇨🇦 · Zhu-Feng Zhang🇨🇳 · Hong-Ying Jin🇨🇳

   We study the exotic $J^{PC}=0^{--}$ four-quark states in Laplace sum rules (LSR) and finite energy sum rules (FESR). We use the vector tetraquark-like currents as interpolating currents in the correlator, from which the $1^{+-}$ states are also studied. In the mass extraction, we use the standard stability criterion with respect to the Borel parameters and the QCD continuum thresholds and consider the effect of the violation of factorization in estimating the high dimensional condensates as a source of uncertainties. The obtained mass prediction $1.66\pm 0.14$ GeV is much lower than the previous sum rule predictions obtained using the scalar currents. Our result favours the four-quark interpretation of the possible $\rho \pi$ dominance in the $D^0$ decay. We also discuss the possible decay patterns of these exotic four-quark states.

   hep-phhep-exhep-latPRD(2017)·30 citations
7. 07*

   Analysis of BaBar, Belle, BES-II, CLEO and KEDR data on $\psi (3770)$ line shape and determination of the resonance parameters

   A.G. Shamov🇷🇺 · K.Yu. Todyshev🇷🇺

   The available data on the $D\overline{D}$ and inclusive hadronic cross sections in the $\psi (3770)$ region from the BaBar, Belle, BES-II, CLEO and KEDR experiments have been analyzed assuming that systematic uncertainties on cross sections measured by different detectors are not correlated. Four theoretical models predicting the $\psi (3770)$ line shape were considered for the $D\overline{D}$ channel. All of them gave satisfactory description of the data. The combined analysis of the $D\overline{D}$ and inclusive hadronic channel was performed using the model based on the vector dominance approach and accounting for the contribution of the $\psi (2S)$ tail to the $D\overline{D}$ cross section. The following values of the mass, total width, electron width and decay probability to the non-$D\overline{D}$ states were obtained: $M=3779.8\pm 0.6\text{MeV},\Gamma =25.8\pm 1.3\text{MeV},{\Gamma }_{ee}=196\pm 18\text{eV},{\mathcal{B}}_{nD\overline{D}}=0.164\pm 0.049$, where the errors quoted include both statistical and dominant systematic uncertainties.

   hep-phPLB(2017)·11 citations
8. 08*

   Top-quark loop corrections in Z+jet and Z+2 jet production

   John M. Campbell🇺🇸 · R. Keith Ellis🇬🇧

   The sophistication of current predictions for $Z+$jet production at hadron colliders necessitates a re-evaluation of any approximations inherent in the theoretical calculations. In this paper we address one such issue, the inclusion of mass effects in top-quark loops. We ameliorate an existing calculation of $Z+1$~jet and $Z+2$~jet production by presenting exact analytic formulae for amplitudes containing top-quark loops that enter at next-to-leading order in QCD. Although approximations based on an expansion in powers of $1/m_t^2$ can lead to poor high-energy behavior, an exact treatment of top-quark loops demonstrates that their effect is small and has limited phenomenological interest.

   hep-phJHEP(2017)·12 citations
9. 09*

   Scale genesis and gravitational wave in a classically scale invariant extension of the standard model

   Jisuke Kubo🇯🇵 · Masatoshi Yamada🇩🇪

   We assume that the origin of the electroweak (EW) scale is a gauge-invariant scalar-bilinear condensation in a strongly interacting non-abelian gauge sector, which is connected to the standard model via a Higgs portal coupling. The dynamical scale genesis appears as a phase transition at finite temperature, and it can produce a gravitational wave (GW) background in the early Universe. We find that the critical temperature of the scale phase transition lies above that of the EW phase transition and below few $O(100)$ GeV and it is strongly first-order. We calculate the spectrum of the GW background and find the scale phase transition is strong enough that the GW background can be observed by DECIGO.

   hep-phJCAP(2016)·41 citations
10. 10*

    Extended Higgs sectors in the context of supersymmetry at the LHC

    Priyotosh Bandyopadhyay🇮🇹

    We studied the extension of Standard Model (SM) Higgs sector with $SU(2)$ triplet and SM gauge singlet in the context of supersymmetry. For a $Z_3$ symmetric superpotential where the singlet field generates the bi-linear Higgs mixing term between two Higgs doublets dynamically. Models like this often have a very light pseudoscalar as pseudo-Nambu Goldstone model of an extra $U(1)$ symmetry. We investigate the possibility of such light hidden Higgs boson with the data of the discovered Higgs boson around 125 GeV. Along with the neutral sector, the charged Higgs bosons in the triplet extended case are really interesting as the triplet charged Higgs bosons give rise to new decay mode to $Z{W}^{\pm }$ along with $a_1{W}^{\pm }$ due to the existence of light pseudoscalar. These new modes can be looked for at the LHC in the search for the Higgs bosons in other representations of $SU(2)$.

    hep-phEPJ Web Conf.(2016)·0 citations
11. 11*

    The exclusive $J/\psi$ process at the LHC tamed to probe the low $x$ gluon

    S.P. Jones🇩🇪 · A.D. Martin🇬🇧 · M.G. Ryskin🇬🇧 · T. Teubner🇬🇧

    The perturbative QCD expansion for $J/\psi$ photoproduction appears to be unstable: the NLO correction is large (and of opposite sign) to the LO contribution. Moreover, the predictions are very sensitive to the choice of factorization and renormalization scales. Here we show that perturbative stability is greatly improved by imposing a $‘Q_0$ cut' on the NLO coefficient functions; a cut which is required to avoid double counting. $Q_0$ is the input scale used in the parton DGLAP evolution. This result opens the possibility of high precision exclusive $J/\psi$ data in the forward direction at the LHC being able to determine the low $x$ gluon distribution at low scales.

    hep-phEPJC(2016)·55 citations
12. 12*

    Prompt photon production and photon-hadron jet correlations with POWHEG

    T. Jezo🇮🇹 · M. Klasen🇩🇪 · F. König🇩🇪

    We present a calculation of direct photon production at next-to-leading order of QCD and a matching of this calculation with parton showers using POWHEG BOX. Based on simulations with POWHEG+PYTHIA, we perform a detailed phenomenological analysis of PHENIX data on prompt photon production and photon-hadron jet correlations in pp collisions at RHIC, considerably improving the description of these data with respect to previous calculations, and we suggest additional interesting analyses.

    hep-phhep-exnucl-exnucl-thJHEP(2016)·30 citations
13. 13*

    A testable radiative neutrino mass model without additional symmetries and Explanation for the $b\to s{\ell }^{+}{\ell }^{-}$ anomaly

    Kingman Cheung🇹🇼 · Takaaki Nomura🇰🇷 · Hiroshi Okada🇹🇼

    We propose a one-loop radiative Majorana-type neutrino-mass matrix without any kind of additional symmetries by introducing two leptoquark-like bosons only. In this scenario, we show that the anomaly appearing in the process $b\to s\ell \bar{\ell }$ can be explained without any conflicts against various constraints such as lepton-flavor violations, flavor-changing neutral currents, oblique parameters $\Delta S,\Delta T$, and the Drell-Yan process. We make the predictions for the flavor-violating lepton-pair production ($e\mu$, $e\tau$, and $\mu \tau$) at the LHC, as well as the cross sections for pair production of these leptoquark-like bosons.

    hep-phPRD(2016)·36 citations
14. 14*

    Holography, Hydrodynamization and Heavy-Ion Collisions

    Michal P. Heller🇨🇦

    In the course of the past several years holography has emerged as an ab initio tool in exploring strongly-time-dependent phenomena in gauge theories. These lecture notes overview recent developments in this area driven by phenomenological questions concerning applicability of hydrodynamics (hydrodynamization) under extreme conditions occurring in ultrarelativistic heavy-ion collisions at RHIC and LHC. The topics include hydrodynamization time scale, holographic collisions, as well as hydrodynamization from the point of view of the asymptotic character of the hydrodynamic gradient expansion. The emphasis is put on concepts rather than calculational techniques and a particular attention is devoted to present these developments in the context of the most recent advances and some of the open problems.

    ↳ hep-thhep-phnucl-thActa Phys.Polon.B(2016)·49 citations
15. 15*

    Viscosity of a net-baryon fluid near the QCD critical point

    N.G. Antoniou🇬🇷 · F.K. Diakonos🇬🇷 · A.S. Kapoyannis🇬🇷

    In the dynamics of the QCD critical point, the net-baryon fluid, linked to the slow component of the order parameter, relaxes to a 3d Ising system in equilibrium. An analytical study of shear and bulk viscosity, with constraints imposed by the dynamics of the critical net-baryon fluid, the universality property and the requirements of a class of strong coupling theories, is performed in the neighbourhood of the critical point. It is found that the shear viscosity of the net-baryon fluid is restricted in the domain $1.6\le 4\pi \frac{\eta }{s}\le 3.7$ for $T_c<T\le 2T_c$ whereas the bulk viscosity is small, $4\pi \frac{\zeta }{s}<0.05$ (for $T>1.27T_c$) but rising towards the singularity at $T=T_c$.

    ↳ nucl-thhep-phPRC(2017)·7 citations
16. 16*

    Chiral Closed strings: Four massless states scattering amplitude

    Marcelo M. Leite🇺🇸 · Warren Siegel🇺🇸

    We compute the scattering amplitudes of four massless states for chiral (closed) bosonic and type II superstrings using the Kawai-Lewellen-Tye ($KLT$) factorization method. The amplitude in the chiral bosonic case is identical to a field theory amplitude corresponding to the spin-$2$ tachyon, massless gravitational sector and massive spin-2 tardyon states of the spectrum. Chiral type II superstrings amplitude only possess poles associated with the massless gravitational sector. We briefly discuss the extension of the calculation to heterotic superstrings.

    ↳ hep-thhep-phmath-phmath.MPJHEP(2017)·20 citations
17. 17*

    1+1 Large $N_c$ QCD and its Holographic Dual -Soliton Picture of Baryons in Single-Flavor World

    Hideo Suganuma🇯🇵 · Yuya Nakagawa🇯🇵 · Kohei Matsumoto (Kyoto U.)🇯🇵

    We study baryons in holographic QCD corresponding to 1+1 dimensional single-flavor ($N_f$=1) QCD for the first time. We formulate 1+1 QCD using an $S^1$-compactified D2/D8/$\overline{D8}$ branes in the superstring theory, and describe the baryon as a topological configuration in 1+1 $N_f$=1 QCD, corresponding to ${\Pi }_1(\mathrm{U}(1))=\mathbf{Z}$. Unlike 1+3 QCD with $N_f\ge 2$, however, we find that the low-dimensional baryonic soliton is generally unstable against a scale transformation/variation and swells infinitely in 1+1 $N_f$=1 QCD at the leading of large $N_c$. We thus point out a serious difficulty on the soliton picture of baryons in large $N_c$ in the single-flavor world in both 1+1 and 1+3 QCD. We also compare the low-dimensional holographic baryon with the Abrikosov vortex, i.e., a stable topological configuration in Type-II superconductors.

    ↳ hep-thhep-phmath-phmath.MPJPS Conf.Proc.(2017)·0 citations
18. 18*

    Modeling dark matter subhalos in a constrained galaxy: Global mass and boosted annihilation profiles

    Martin Stref🇫🇷 · Julien Lavalle🇫🇷

    The interaction properties of cold dark matter (CDM) particle candidates, such as those of weakly interacting massive particles (WIMPs), generically lead to the structuring of dark matter on scales much smaller than typical galaxies, potentially down to $\sim 10^{-10}{M}_{\odot }$. This clustering translates into a very large population of subhalos in galaxies and affects the predictions for direct and indirect dark matter searches (gamma rays and antimatter cosmic rays). In this paper, we elaborate on previous analytic works to model the Galactic subhalo population, while consistently with current observational dynamical constraints on the Milky Way. In particular, we propose a self-consistent method to account for tidal effects induced by both dark matter and baryons. Our model does not strongly rely on cosmological simulations as they can hardly be fully matched to the real Milky Way, but for setting the initial subhalo mass fraction. Still, it allows to recover the main qualitative features of simulated systems. It can further be easily adapted to any change in the dynamical constraints, and be used to make predictions or derive constraints on dark matter candidates from indirect or direct searches. We compute the annihilation boost factor, including the subhalo-halo cross-product. We confirm that tidal effects induced by the baryonic components of the Galaxy play a very important role, resulting in a local average subhalo mass density $\lesssim 1\%$ of the total local dark matter mass density, while selecting in the most concentrated objects and leading to interesting features in the overall annihilation profile in the case of a sharp subhalo mass function. Values of global annihilation boost factors range from $\sim 2$ to $\sim 20$, while the local annihilation rate is about half as much boosted.

    ↳ astro-ph.COastro-ph.HEhep-phPRD(2017)·66 citations
19. 19*

    Impact of CP-violation on neutrino lepton number asymmetries revisited

    Gabriela Barenboim🇪🇸 · Wan-Il Park🇪🇸

    We revisit the effect of the (Dirac) CP-violating phase on neutrino lepton number asymmetries in both mass- and flavor-basis. We found that, even if there are sizable effects on muon- and tau-neutrino asymmetries, the effect on the asymmetry of electron-neutrinos is at most similar to the upper bound set by BBN for initial neutrino degeneracy parameters smaller than order unity. We also found that, for the asymmetries in mass-basis, the changes caused by CP-violation is of sub-\% level which is unlikely to be accesible neither in the current nor in the forthcoming experiments.

    ↳ astro-ph.COhep-phPLB(2017)·4 citations
20. 20*

    Analysis of hadron yield data within hadron resonance gas model with multi-component eigenvolume corrections

    Volodymyr Vovchenko🇩🇪 · Horst Stoecker🇩🇪

    We analyze the sensitivity of thermal fits to heavy-ion hadron yield data of ALICE and NA49 collaborations to the systematic uncertainties in the hadron resonance gas (HRG) model related to the modeling of the eigenvolume interactions. We find a surprisingly large sensitivity in extraction of chemical freeze-out parameters to the assumptions regarding eigenvolumes of different hadrons. We additionally study the effect of including yields of light nuclei into the thermal fits to LHC data and find even larger sensitivity to the modeling of their eigenvolumes. The inclusion of light nuclei yields, thus, may lead to further destabilization of thermal fits. Our results show that modeling of eigenvolume interactions plays a crucial role in thermodynamics of HRG and that conclusions based on a non-interacting HRG are not unique.

    ↳ nucl-thhep-phJ.Phys.Conf.Ser.(2017)·15 citations
21. 21*

    Cumulative pion production via successive collisions in nuclear medium

    A. Motornenko🇺🇦 · M. I. Gorenstein🇺🇦

    Production of pions in proton-nucleus (p+A) reactions outside of a kinematical boundary of proton-nucleon collisions, the so-called cumulative effect, is studied. The kinematical restrictions on pions emitted in backward direction in the target rest frame are analyzed. It is shown that cumulative pion production requires a presence of massive baryonic resonances that are produced during successive collisions of projectile with nuclear nucleons. After each successive collision the mass of created resonance may increase and, simultaneously, its longitudinal velocity decreases. Simulations within Ultra relativistic Quantum Molecular Dynamics model reveals that successive collisions of baryonic resonances with nuclear nucleons plays the dominant role in cumulative pion production in p+A reactions.

    ↳ nucl-thhep-phActa Phys.Polon.Supp.(2017)·1 citation
22. 22*

    Small $x$ gluon shadowing from LHC data on coherent $J/\psi$ photoproduction

    J. G. Contreras🇨🇿

    The cross section for coherent $J/\psi$ photoproduction in Pb-Pb collisions is the sum of two contributions, one from low-, the other from high-energy photon-nucleus interactions. A novel method to disentangle both contributions allowing one to extract the coherent photo-nuclear cross section for coherent $J/\psi$ production, ${\sigma }_{\gamma \mathrm{Pb}}$, is presented. The utility of the method is demonstrated using measurements from peripheral and ultra-peripheral Pb-Pb collisions at the LHC. Applying the proposed method to the available data it is possible to obtain ${\sigma }_{\gamma \mathrm{Pb}}$ up to a photon-lead centre-of-mass energy of 470 GeV, which corresponds to $x$ of 4.4x10${}^{-5}$. To illustrate a possible use of the extracted photo-nuclear cross sections, the corresponding nuclear suppression factors are computed and they are compared to predictions of gluon shadowing calculated in the leading-twist approximation approach.

    ↳ nucl-exhep-phPRC(2017)·56 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.