Tue·Jul 21, 2015Tuesday·July 21, 2015

1. 01*

   One-loop triple collinear splitting amplitudes in QCD

   Simon Badger🇬🇧 · Francesco Buciuni🇬🇧 · Tiziano Peraro🇬🇧

   We study the factorisation properties of one-loop scattering amplitudes in the triple collinear limit and extract the universal splitting amplitudes for processes initiated by a gluon. The splitting amplitudes are derived from the analytic Higgs plus four partons amplitudes. We present compact results for primitive helicity splitting amplitudes making use of super-symmetric decompositions. The universality of the collinear factorisation is checked numerically against the full colour six parton squared matrix elements.

   hep-phJHEP(2015)·41 citations
2. 02*

   Higgs mass predictions of public NMSSM spectrum generators

   Florian Staub🇨🇭 · Peter Athron🇦🇺 · Ulrich Ellwanger🇫🇷 · Ramona Grober🇮🇹 · Margarete Muhlleitner🇩🇪 · Pietro Slavich🇫🇷 · Alexander Voigt🇩🇪

   The publicly available spectrum generators for the NMSSM often lead to different predictions for the mass of the standard model-like Higgs boson even if using the same renormalization scheme and two-loop accuracy. Depending on the parameter point, the differences can exceed 5 GeV, and even reach 8 GeV for moderate superparticle masses of up to 2 TeV. It is shown here that these differences can be traced back to the calculation of the running standard model parameters entering all calculations, to the approximations used in the two-loop corrections included in the different codes, and to different choices for the renormalization conditions and scales. In particular, the importance of the calculation of the top Yukawa coupling is pointed out.

   hep-phhep-exComput.Phys.Commun.(2016)·68 citations
3. 03*

   Muon g-2 and galactic centre $\gamma$-ray excess in a scalar extension of the 2HDM type-X

   Andi Hektor🇪🇪 · Kristjan Kannike🇪🇪 · Luca Marzola🇪🇪

   We consider an extension of the lepto-specific 2HDM with an extra singlet $S$ as a dark matter candidate. Taking into account theoretical and experimental constraints, we investigate the possibility to address both the $\gamma$-ray excess detected at the Galactic centre and the discrepancy between the Standard Model prediction and experimental results of the anomalous magnetic moment of the muon. Our analyses reveal that the $SS\to {\tau }^{+}{\tau }^{-}$ and $SS\to b\bar{b}$ channels reproduce the Galactic centre excess, with an emerging dark matter candidate which complies with the bounds from direct detection experiments, measurements of the Higgs boson invisible decay width and observations of the dark matter relic abundance. Addressing the anomalous magnetic moment of the muon imposes further strong constraints on the model. Remarkably, under these conditions, the $SS\to b\bar{b}$ channel still allows for the fitting of the Galactic centre. We also comment on a scenario allowed by the model where the $SS\to {\tau }^{+}{\tau }^{-}$ and $SS\to b\bar{b}$ channels have comparable branching ratios, which possibly yield an improved fitting of the Galactic centre excess.

   hep-phastro-ph.HEJCAP(2015)·18 citations
4. 04*

   Tree-level metastability bounds for the most general two Higgs doublet model

   I. P. Ivanov🇵🇹 · Joao P. Silva🇵🇹

   Within two Higgs doublet models, it is possible that the current vacuum is not the global minimum, in which case it could possibly decay at a later stage. We discuss the tree-level conditions which must be obeyed by the most general scalar potential in order to preclude that possibility. We propose a new procedure which is not only more general but also easier to implement than the previously published one, including CP conserving as well as CP violating scalar sectors. We illustrate these conditions within the context of the Z2 model, softly broken by a complex, CP violating parameter.

   hep-phPRD(2015)·85 citations
5. 05*

   Resummation of Large Logarithms in the Rapidity Evolution of Color Dipoles

   E. Iancu🇫🇷 · J.D. Madrigal🇫🇷 · A.H. Mueller🇺🇸 · G. Soyez🇫🇷 · D.N. Triantafyllopoulos🇮🇹

   Perturbative corrections beyond leading-log accuracy to BFKL and BK equations, describing the rapidity evolution of QCD scattering amplitudes at high energy, exhibit strong convergence problems due to radiative corrections enhanced by large single and double transverse logs. We identify explicitly the physical origin of double transverse logs and resum them directly in coordinate space as appropriate for BK equation, in terms of an improved local-in-rapidity evolution kernel. Numerical results show the crucial role of double-logarithmic resummation for BK evolution, which is stabilized and slowed down by roughly a factor of two.

   hep-phPoS(2015)·0 citations
6. 06*

   Nucleon-decay-like signatures of Hylogenesis

   S.V. Demidov🇷🇺 · D.S. Gorbunov🇷🇺

   We consider nucleon-decay-like signatures of the hylogenesis, a variant of the antibaryonic dark matter model. For the interaction between visible and dark matter sectors through the neutron portal, we calculate the rates of dark matter scatterings off neutron which mimic neutron-decay processes $n\to \nu \gamma$ and $n\to \nu e^{+}{e}^{-}$ with richer kinematics. We obtain bounds on the model parameters from nonobservation of the neutron decays by applying the kinematical cuts adopted in the experimental analyses. The bounds are generally (much) weaker than those coming from the recently performed study of events with a single jet of high transverse momentum and missing energy observed at the LHC. Then we suggest several new nucleon-decay like processes with two mesons in the final state and estimate (accounting for the LHC constraints) the lower limits on the nucleon lifetime with respect to these channels. The obtained values appear to be promising for probing the antibaryonic dark matter at future underground experiments like HyperK and DUNE.

   hep-phhep-exPRD(2016)·5 citations
7. 07*

   The Proton Mass and Scale-Invariant Hidden Local Symmetry for Compressed Baryonic Matter

   Mannque Rho🇫🇷

   I discuss how to access dense baryonic matter of compact stars by combining hidden local symmetry (HLS) of light-quark vector mesons with spontaneously broken scale invariance of a (pseudo) Nambu-Goldstone boson, dilaton, in a description that parallels the approach to dilatonic Higgs. Some of the surprising observations are that the bulk of proton mass is not Nambu-Goldstonian, parity doubling emerges at high density and the EoS of baryonic matter can be soft enough for heavy-ion processes at low density and stiff enough at high density for $\sim 2$ solar mass neutron stars.

   hep-phnucl-thInt.J.Mod.Phys.A(2017)·4 citations
8. 08*

   BCVEGPY2.2: A Newly Upgraded Version for Hadronic Production of the Meson $B_c$ and Its Excited States

   Chao-Hsi Chang🇨🇳 · Xian-You Wang🇨🇳 · Xing-Gang Wu🇨🇳

   A newly upgraded version of the BCVEGPY, a generator for hadronic production of the meson $B_c$ and its excited states, is available. In comparison with the previous one [C.H. Chang, J.X. Wang and X.G. Wu, Comput. Phys. Commun. {\bf 175}, 624 (2006)], the new version is to apply an improved hit-and-miss technology to generating the un-weighted events much more efficiently under various simulation environments. The codes for production of $2S$-wave $B_c$ states are also given here.

   hep-phComput.Phys.Commun.(2015)·33 citations
9. 09*

   CP breaking in $S(3)$ flavoured Higgs model

   E. Barradas-Guevara🇲🇽 · O. Félix-Beltrán🇲🇽 · E. Rodríguez-Jáuregui🇲🇽

   We analyze the Higgs sector of the minimal $S(3)$-invariant extension of the Standard Model including CP violation arising from the spontaneous electroweak symmetry breaking. This extended Higgs sector includes three SU(2) doublets Higgs fields with complex vev's providing an interesting scenario to analyze the Higgs masses spectrum, trilinear Higgs self-couplings and CP violation. We present how the spontaneous electroweak symmetry breaking coming from three $S(3)$ Higgs fields gives an interesting scenario with nine physical Higgs and three Goldstone bosons when spontaneous CP violation arises from the Higgs field $S(3)$ singlet $H_S$. Furthermore, a numerical analysis of the Higgs masses and trilinear Higgs self-couplings is presented. Particularly, we find a physical solution for the scenario in which spontaneous CPB is provided by $H_S$. In this scheme, the scalar Higgs $H_1^0$ is identified, whose mass is 125 GeV and ${\lambda }_{H_1^0{H}_1^0{H}_1^0}\sim {\lambda }_{h^0{h}^0{h}^0}^{SM}$.

   hep-ph11 citations
10. 10*

    $\bar{D}{\Sigma }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Sigma }_c$ interactions and the LHCb hidden-charmed pentaquarks

    Jun He🇨🇳

    Very recently, two hidden-charmed resonances $P_c(4380)$ and $P_c(4450)$ consistent with pentaquark states were observed at the LHCb detector. The two $P_c$ states locate just below the $\bar{D}{\Sigma }_c^{\ast }$ and ${\bar{D}}^{\ast }{\Sigma }_c$ thresholds with mass of gaps about 5 and 15 MeV, respectively. Inspired by this fact we perform a dynamical investigation about the $\bar{D}{\Sigma }_c^{\ast }(2520)$ and ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ interactions which are described by the meson exchanges. A bound state which carries spin-parity $J^P=3/2^{-}$ is produced from the $\bar{D}{\Sigma }_c^{\ast }(2520)$ interaction, which is consistent with the $P_c(4380)$ observed at the LHCb detector. From the $D^{\ast }{\Sigma }_c(2455)$ interaction, a bound state with $5/2^{+}$ is produced, which can be related to the $P_c(4450)$. The results suggest that the $P_c(4380)$ and $P_c(4450)$ are good candidates of $\bar{D}{\Sigma }_c^{\ast }(2520)$ and ${\bar{D}}^{\ast }{\Sigma }_c(2455)$ molecular states, respectively.

    hep-phhep-exhep-latnucl-ex+1PLB(2016)·256 citations
11. 11*

    Comment on "Axion induced oscillating electric dipole moments"

    V. V. Flambaum🇦🇺 · B. M. Roberts🇦🇺 · Y. V. Stadnik🇦🇺

    In the recent work [Phys. Rev. D 91, 111702(R) (2015)], C. Hill concludes that the axion electromagnetic anomaly induces an oscillating electron electric dipole moment of frequency $m_a$ and strength $\sim 10^{-32}e$ cm, in the limit $v/c\to 0$ for the axion field. Here, we demonstrate that a proper treatment of this problem in the lowest order yields $\text{no}$ electric dipole moment of the electron in the same limit. Instead, oscillating electric dipole moments of atoms and molecules are produced by different mechanisms.

    hep-phastro-ph.COphysics.atom-phPRD(2017)·13 citations
12. 12*

    Transverse momentum dependent (TMD) parton distribution functions: status and prospects

    R. Angeles-Martinez🇬🇧 · A. Bacchetta🇮🇹 · I.I. Balitsky🇺🇸 · D. Boer🇳🇱 · M. Boglione🇮🇹 · R. Boussarie🇫🇷 · F.A. Ceccopieri🇧🇪 · I.O. Cherednikov🇧🇪 · P. Connor🇩🇪 · M.G. Echevarria🇳🇱 · G. Ferrera🇮🇹 · J. Grados Luyando🇩🇪 and 25 other authors

    We provide a concise overview on transverse momentum dependent (TMD) parton distribution functions, their application to topical issues in high-energy physics phenomenology, and their theoretical connections with QCD resummation, evolution and factorization theorems. We illustrate the use of TMDs via examples of multi-scale problems in hadronic collisions. These include transverse momentum q_T spectra of Higgs and vector bosons for low q_T, and azimuthal correlations in the production of multiple jets associated with heavy bosons at large jet masses. We discuss computational tools for TMDs, and present an application of a new tool, TMDlib, to parton density fits and parameterizations.

    hep-phActa Phys.Polon.B(2015)·388 citations
13. 13*

    Solar neutrinos and neutrino physics

    Michele Maltoni🇪🇸 · Alexei Yu. Smirnov🇩🇪

    Solar neutrino studies triggered and largely motivated the major developments in neutrino physics in the last 50 years. Theory of neutrino propagation in different media with matter and fields has been elaborated. It includes oscillations in vacuum and matter, resonance flavor conversion and resonance oscillations, spin and spin-flavor precession, etc. LMA MSW has been established as the true solution of the solar neutrino problem. Parameters theta12 and Delta_m21^2 have been measured; theta13 extracted from the solar data is in agreement with results from reactor experiments. Solar neutrino studies provide a sensitive way to test theory of neutrino oscillations and conversion. Characterized by long baseline, huge fluxes and low energies they are a powerful set-up to search for new physics beyond the standard 3nu paradigm: new neutrino states, sterile neutrinos, non-standard neutrino interactions, effects of violation of fundamental symmetries, new dynamics of neutrino propagation, probes of space and time. These searches allow us to get stringent, and in some cases unique bounds on new physics. We summarize the results on physics of propagation, neutrino properties and physics beyond the standard model obtained from studies of solar neutrinos.

    hep-phastro-ph.SRhep-exEPJA(2016)·147 citations
14. 14*

    Singlet axial-vector coupling constant of the nucleon in QCD without instantons

    Janardan P. Singh🇮🇳

    We have analyzed axial-vector current-current correlation functions between one-nucleon states to calculate the singlet axial-vector coupling constant of the nucleon. The octet-octet and the octet-singlet current correlators, investigated in this work, do not require any use of instanton effects. The QCD and hadronic parameters used for the evaluation of correlators have been varied by (10 - 20)%. The value of the singlet axial-vector coupling constant of the nucleon obtained from this analysis is consistent with its current determination from experiments and QCD theory.

    hep-phPLB(2015)·4 citations
15. 15*

    Stringy origin of diboson and dijet excesses at the LHC

    Luis A. Anchordoqui🇺🇸 · Ignatios Antoniadis🇫🇷 · Haim Goldberg🇺🇸 · Xing Huang🇹🇼 · Dieter Lust🇩🇪 · Tomasz R. Taylor🇺🇸

    Very recently, the ATLAS and CMS collaborations reported diboson and dijet excesses above standard model expectations in the invariant mass region of 1.8 -2.0 TeV. Interpreting the diboson excess of events in a model independent fashion suggests that the vector boson pair production searches are best described by WZ or ZZ topologies, because states decaying into W^+W^- pairs are strongly constrained by semileptonic searches. Under the assumption of a low string scale, we show that both the diboson and dijet excesses can be steered by an anomalous U(1) field with very small coupling to leptons. The Drell-Yan bounds are then readily avoided because of the leptophobic nature of the massive Z' gauge boson. The non-negligible decay into ZZ required to accommodate the data is a characteristic footprint of intersecting D-brane models, wherein the Landau-Yang theorem can be evaded by anomaly-induced operators involving a longitudinal Z. The model presented herein can be viewed purely field-theoretically, although it is particularly well motivated from string theory. Should the excesses become statistically significant at the LHC13, the associated Z\gamma{} topology would become a signature consistent only with a stringy origin.

    hep-phhep-thPLB(2015)·32 citations
16. 16*

    ATLAS Diboson Excesses from the Stealth Doublet Model

    Wei Chao🇺🇸

    The ATLAS collaboration has reported excesses in diboson invariant mass searches of new resonances around 2 TeV, which might be a prediction of new physics around that mass range. We interpret these results in the context of a modified stealth doublet model where the extra Higgs doublet has a Yukawa interaction with the first generation quarks, and show that the heavy CP-even Higgs boson can naturally explain the excesses in the WW and ZZ channels with a small Yukawa coupling, \xi\sim 0.15, and a tiny mixing angle with the SM Higgs boson, \alpha \sim 0.06. Furthermore, the model satisfy constraints from colliders and electroweak precision measurements.

    hep-phhep-exPLB(2016)·26 citations
17. 17*

    Combining parton showers and NNLO matrix elements

    Stefan Hoeche🇺🇸 · Ye Li🇺🇸 · Stefan Prestel🇺🇸

    In this talk, we discuss recent developments in combining parton showers and fixed-order calculations. We focus on the UNNLOPS method for matching next-to-next-to-leading order computations to the parton shower, and we present results from Sherpa for Drell-Yan lepton-pair and Higgs-boson production at the LHC.

    hep-ph3 citations
18. 18*

    Understanding the newly observed heavy pentaquark candidates

    Xiao-Hai Liu🇯🇵 · Qian Wang🇩🇪 · Qiang Zhao🇨🇳

    We find that several thresholds can contribute to the enhancements of the newly observed heavy pentaquark candidates $P_c^{+}(4380)$ and $P_c^{+}(4450)$ via the anomalous triangle singularity (ATS) transitions in the specific kinematics of ${\Lambda }_b\to J/\psi K^{-}p$. Apart from the observed two peaks we find that another peaks around 4.5 GeV can also be produced by the ATS. We also show that the ${\Sigma }_c^{(\ast )}$ can be produced at leading order in ${\Lambda }_b$ decay. This process is different from the triangle diagram and its threshold enhancement only appears as CUSP effects if there is no pole structure or the ATS involved. The threshold interaction associated with the presence of the ATS turns out to be a general phenomenon and plays a crucial role in the understanding of candidates for exotic states.

    hep-phhep-exnucl-exnucl-thPLB(2016)·288 citations
19. 19*

    Analytic continuation of nucleon electromagnetic form factors in the time-like region

    Pedro Alberto🇵🇹 · Alessandro Drago🇮🇹 · Alessio Mangoni🇮🇹 · Simone Moretti🇬🇧 · Simone Pacetti🇮🇹

    The possibility to compute nucleon electromagnetic form factors in the time-like region by analytic continuation of their space-like expressions has been explored in the framework of the Skyrme model. We have developed a procedure to solve analytically Fourier transforms of the nucleon electromagnetic current and hence to obtain form factors defined in all kinematical regions and fulfilling the first-principles requirements. The results are discussed and compared to data, both in space-like and time-like region.

    hep-phhep-thJ.Phys.G(2021)·4 citations
20. 20*

    Thermodynamics of the low density excluded volume hadron gas

    Krzysztof Redlich🇵🇱 · Kacper Zalewski🇵🇱

    We consider thermodynamics of the excluded volume particles at finite temperature and chemical potential, in the low density approximation. We assume Boltzmann statistics and study the influence of the excluded volume on an ideal gas thermodynamics at the same temperature, pressure and numbers of particles. We show, that considering the change of the free enthalpy due to the excluded volume, and using the Maxwell identities, one can derive relevant thermodynamic functions and parameters of multi-component gases. The derivation is quite general as particles may have different sizes and shapes which can also depend on their momenta. Besides it's simplicity and generality, our approach has the advantage of eliminating the transcendental equations occurring in earlier studies. A representative example of the excluded volume thermodynamics is the single-component gas of hard spheres. For this case, using the viral expansion, the validity limits of the low-density approximation are also discussed.

    hep-phnucl-exPRC(2016)·16 citations
21. 21*

    Annihilation of Relativistic Positrons in Single Crystal with production of One Photon

    Nikolay Kalashnikov🇷🇺 · Evgeny Mazur🇷🇺 · Andrzej Olczak🇷🇺

    The energy and momentum conservation laws prohibit positron-electron annihilation in vacuum producing the single photon only. It can produce two photons in vacuum, or the process is possible with a participation of the third body. The situation is different in a single crystal with one of the leptons (e.g. positron) moving in the channeling (or in the quasi-channeling) mode when the transverse motion of a particle is bound or sufficiently uneven. It may increase sharply the probability of the single photon annihilation process.

    hep-phcond-mat.otherphysics.acc-phInt.J.Mod.Phys.A(2015)·1 citation
22. 22*

    Neutron-antineutron Oscillation and Baryonic Majoron: Low Scale Spontaneous Baryon Violation

    Zurab Berezhiani🇮🇹

    We discuss a possibility that baryon number $B$ is spontaneously broken at low scales, of the order of MeV or even smaller, so that the neutron-antineutron oscillation can be induced at the experimentally accessible level. An associated Goldstone particle, baryonic majoron, can have observable effects in neutron to antineutron transitions in nuclei or dense nuclear matter. By extending baryon number to $B-L$ symmetry, baryo-majoron can be identified with the ordinary majoron associated with the spontaneous breaking of lepton number, with interesting implications for neutrinoless $2\beta$ becay with the majoron emission, etc. We also discuss a hypothesis suggesting that baryon number maybe spontaneously broken by the QCD itself via the six-quark condensates.

    hep-phEPJC(2016)·73 citations
23. 23*

    JUNO and Neutrinoless Double Beta Decay

    Shao-Feng Ge🇩🇪 · Werner Rodejohann🇩🇪

    We study the impact of the precision determination of oscillation parameters in the JUNO experiment on half-life predictions for neutrinoless double beta decay. We show that the solar neutrino mixing angle can be measured by JUNO with below 1% uncertainty. This implies in particular that the minimal value of the effective mass in the inverted mass ordering will be known essentially without uncertainty. We demonstrate that this reduces the range of half-life predictions in order to test this value by a factor of two. The remaining uncertainty is caused by nuclear matrix elements. This has important consequences for future double beta decay experiments that aim at ruling out the inverted mass ordering or the Majorana nature of neutrinos.

    hep-phhep-exnucl-exnucl-thPRD(2015)·26 citations
24. 24*

    Gamma ray tests of Minimal Dark Matter

    Marco Cirelli🇫🇷 · Thomas Hambye🇧🇪 · Paolo Panci🇫🇷 · Filippo Sala🇫🇷 · Marco Taoso🇫🇷

    We reconsider the model of Minimal Dark Matter (a fermionic, hypercharge-less quintuplet of the EW interactions) and compute its gamma ray signatures. We compare them with a number of gamma ray probes: the galactic halo diffuse measurements, the galactic center line searches and recent dwarf galaxies observations. We find that the original minimal model, whose mass is fixed at 9.4 TeV by the relic abundance requirement, is constrained by the line searches from the Galactic Center: it is ruled out if the Milky Way possesses a cuspy profile such as NFW but it is still allowed if it has a cored one. Observations of dwarf spheroidal galaxies are also relevant (in particular searches for lines), and ongoing astrophysical progresses on these systems have the potential to eventually rule out the model. We also explore a wider mass range, which applies to the case in which the relic abundance requirement is relaxed. Most of our results can be safely extended to the larger class of multi-TeV WIMP DM annihilating into massive gauge bosons.

    hep-phastro-ph.HEJCAP(2015)·123 citations
25. 25*

    Gamma-rays from Heavy Minimal Dark Matter

    Camilo Garcia-Cely🇧🇪 · Alejandro Ibarra🇩🇪 · Anna S. Lamperstorfer🇩🇪 · Michel H.G. Tytgat🇧🇪

    We consider the annihilation into gamma rays of Minimal Dark Matter candidates in the fermionic 5-plet and scalar 7-plet representations of $SU(2{)}_L$, taking into account both the Sommerfeld effect and the internal bremsstrahlung. Assuming the Einasto profile, we show that present measurements of the Galactic Center by the H.E.S.S. instrument exclude the 5-plet and 7-plet as the dominant form of dark matter for masses between 1 TeV and 20 TeV, in particular, the 5-plet mass leading to the observed dark matter density via thermal freeze-out. We also discuss prospects for the upcoming Cherenkov Telescope Array, which will be able to probe even heavier dark matter masses, including the scenario where the scalar 7-plet is thermally produced.

    hep-phastro-ph.COJCAP(2015)·80 citations
26. 26*

    Initial state fluctuations from mid-peripheral to ultra-central collisions in a event-by-event transport approach

    Salvatore Plumari🇮🇹 · Giovanni Luca Guardo🇮🇹 · Francesco Scardina🇮🇹 · Vincenzo Greco🇮🇹

    We have developed a relativistic kinetic transport approach that incorporates initial state fluctuations allowing to study the build up of elliptic flow $v_2$ and high order harmonics $v_3$, $v_4$ and $v_5$ for a fluid at fixed $\eta /s(T)$. We study the effect of the $\eta /s$ ratio and its T dependence on the build up of the $v_n(p_T)$ for two different beam energies: RHIC for Au+Au at $\sqrt{s}=200GeV$ and LHC for $Pb+Pb$ at $\sqrt{s}=2.76TeV$. We find that for the two different beam energies considered the suppression of the $v_n(p_T)$ due to the viscosity of the medium have different contributions coming from the cross over or QGP phase. Our study reveals that only in ultra-central collisions ($0-0.2\%$) the $v_n(p_T)$ have a stronger sensitivity to the T dependence of $\eta /s$ in the QGP phase and this sensitivity increases with the order of the harmonic n. Moreover, the study of the correlations between the initial spatial anisotropies ${ϵ}_n$ and the final flow coefficients $v_n$ shows that at LHC energies there is more correlation than at RHIC energies. The degree of correlation increases from peripheral to central collisions, but only in ultra-central collisions at LHC, we find that the linear correlation coefficient $C(n,n)\approx 1$ for $n=2,3,4$ and $5$. This suggests that the final correlations in the ($v_n$,$v_m$) space reflect the initial correlations in the (${ϵ}_n$,${ϵ}_m$) space.

    hep-phnucl-thPRC(2015)·72 citations
27. 27*

    TMD factorization and evolution at large $b_T$

    John Collins🇺🇸 · Ted C. Rogers🇺🇸

    In using transverse-momentum-dependent (TMD) parton densities and fragmentation functions, important non-perturbative information is at large transverse position $b_T$. This concerns both the TMD functions and their evolution. Fits to high energy data tend to predict too rapid evolution when extrapolated to low energies where larger values of $b_T$ dominate. I summarize a new analysis of the issues. It results in a proposal for much weaker $b_T$ dependence at large $b_T$ for the evolution kernel, while preserving the accuracy of the existing fits. The results are particularly important for using transverse-spin-dependent functions like the Sivers function.

    hep-phPoS(2015)·1 citation
28. 28*

    Perturbation theory of non-perturbative QCD

    Fabio Siringo🇮🇹

    Perturbation theory is shown to be working in the IR limit of pure SU(3) Yang-Mills theory in Landau gauge by an unconventional setting of the perturbative expansion. A dynamical mass is predicted for the gluon and the lattice data are reproduced fairly well by a second-order expansion, without any free parameter. The effective running coupling is small in the IR and the approximation can be improved by inclusion of higher order terms.

    hep-phhep-lathep-th16 citations
29. 29*

    Magnetotransport in Dirac metals: chiral magnetic effect and quantum oscillations

    Gustavo M. Monteiro🇺🇸 · Alexander G. Abanov🇺🇸 · Dmitri E. Kharzeev🇺🇸

    Dirac metals are characterized by the linear dispersion of fermionic quasi-particles, with the Dirac point hidden inside a Fermi surface. We study the magnetotransport in these materials using chiral kinetic theory to describe within the same framework both the negative magnetoresistance caused by chiral magnetic effect and quantum oscillations in the magnetoresistance due to the existence of the Fermi surface. We discuss the relevance of obtained results to recent measurements on $\mathrm{C}{\mathrm{d}}_3\mathrm{A}{\mathrm{s}}_2$.

    ↳ cond-mat.mes-hallhep-phnucl-thPRB(2015)·11 citations
30. 30*

    Weighing neutrinos with cosmic neutral hydrogen

    Francisco Villaescusa-Navarro🇮🇹 · Philip Bull🇳🇴 · Matteo Viel🇮🇹

    We investigate the signatures left by massive neutrinos on the spatial distribution of neutral hydrogen (HI) in the post-reionization era by running hydrodynamic simulations that include massive neutrinos as additional collisionless particles. We find that halos in massive/massless neutrino cosmologies host a similar amount of neutral hydrogen, although for a fixed halo mass, on average, the HI mass increases with the sum of the neutrino masses. Our results show that HI is more strongly clustered in cosmologies with massive neutrinos, while its abundance, ${\Omega }_{\mathrm{HI}}(z)$, is lower. These effects arise mainly from the impact of massive neutrinos on cosmology: they suppress both the amplitude of the matter power spectrum on small scales and the abundance of dark matter halos. Modelling the HI distribution with hydrodynamic simulations at $z>3$, and a simple analytic model at $z<3$, we use the Fisher matrix formalism to conservatively forecast the constraints that Phase 1 of the Square Kilometre Array (SKA) will place on the sum of neutrino masses, $M_{\nu }\equiv \Sigma m_{\nu }$. We find that with 10,000 hours of interferometric observations at $3\lesssim z\lesssim 6$ from a deep and narrow survey with SKA1-LOW, the sum of the neutrino masses can be measured with an error $\sigma (M_{\nu })\lesssim 0.3$ eV (95% CL). Similar constraints can be obtained with a wide and deep SKA1-MID survey at $z\lesssim 3$, using the single-dish mode. By combining data from MID, LOW, and Planck, plus priors on cosmological parameters from a Stage IV spectroscopic galaxy survey, the sum of the neutrino masses can be determined with an error $\sigma (M_{\nu })\simeq 0.06$ eV (95% CL).

    ↳ astro-ph.COhep-phApJ(2015)·88 citations
31. 31*

    Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and $\varphi$ meson in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

    STAR Collaboration: L. Adamczyk · J. K. Adkins · G. Agakishiev · M. M. Aggarwal · Z. Ahammed · I. Alekseev · A. Aparin · D. Arkhipkin · E. C. Aschenauer · G. S. Averichev · X. Bai · V. Bairathi and 323 other authors

    We present high precision measurements of elliptic flow near midrapidity ($|y|<1.0$) for multi-strange hadrons and $\varphi$ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy $\sqrt{s_{NN}}=$ 200 GeV. We observe that the transverse momentum dependence of $\varphi$ and $\Omega$ $v_2$ is similar to that of $\pi$ and $p$, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30$\%$ and 30-80$\%$ collision centrality. There is an indication of the breakdown of previously observed mass ordering between $\varphi$ and proton $v_2$ at low transverse momentum in the 0-30$\%$ centrality range, possibly indicating late hadronic interactions affecting the proton $v_2$.

    ↳ nucl-exhep-exhep-phnucl-thPRL(2016)·120 citations
32. 32*

    Precision Comparison of the Power Spectrum in the EFTofLSS with Simulations

    Simon Foreman🇺🇸 · Hideki Perrier🇨🇭 · Leonardo Senatore🇺🇸

    We study the prediction of the dark matter power spectrum at two-loop order in the Effective Field Theory of Large Scale Structures (EFTofLSS) using high precision numerical simulations. In our universe, short distance non-linear perturbations, not under perturbative control, affect long distance fluctuations through an effective stress tensor that needs to be parametrized in terms of counterterms that are functions of the long distance fluctuating fields. We find that at two-loop order it is necessary to include three counterterms: a linear term in the over density, $\delta$, a quadratic term, ${\delta }^2$, and a higher derivative term, ${\partial }^2\delta$. After the inclusion of these three terms, the EFTofLSS at two-loop order matches simulation data up to $k\simeq 0.34h{\mathrm{Mpc}}^{-1}$ at redshift $z=0$, up to $k\simeq 0.55h{\mathrm{Mpc}}^{-1}$ at $z=1$, and up to $k\simeq 1.1h{\mathrm{Mpc}}^{-1}$ at $z=2$. At these wavenumbers, the cosmic variance of the simulation is at least as small as $10^{-3}$, providing a high precision comparison between theory and data. The actual reach of the theory is affected by theoretical uncertainties associated to not having included higher order terms in perturbation theory, for which we provide an estimate, and by potentially overfitting the data, which we also try to address. Since in the EFTofLSS the coupling constants associated with the counterterms are unknown functions of time, we show how a simple parametrization gives a sensible description of their time-dependence. Overall, the $k$-reach of the EFTofLSS is much larger than previous analytical techniques, showing that the amount of cosmological information amenable to high-precision analytical control might be much larger than previously believed.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2016)·112 citations
33. 33*

    Anti-shadowing Effect on Charmonium Production at a Fixed-target Experiment Using LHC Beams

    Kai Zhou🇨🇳 · Zhengyu Chen🇨🇳 · Pengfei Zhuang🇨🇳

    We investigate charmonium production in Pb+Pb collisions at LHC beam energy $E_{\text{lab}}$=2.76 A TeV at fixed-target experiment ($\sqrt{s_{\text{NN}}}$=72 GeV). In the frame of a transport approach including cold and hot nuclear matter effects on charmonium evolution, we focus on the anti-shadowing effect on the nuclear modification factors $R_{AA}$ and $r_{AA}$ for the $J/\psi$ yield and transverse momentum. The yield is more suppressed at less forward rapidity ($y_{\text{lab}}\simeq$2) than that at very forward rapidity ($y_{\text{lab}}\simeq$4) due to the shadowing and anti-shadowing in different rapidity bins.

    ↳ nucl-thhep-phAdv.High Energy Phys.(2015)·3 citations
34. 34*

    Field of a moving locked charge as applied to beam-beam interactions in storage rings

    Alexander J. Silenko🇧🇾

    It is shown that the Lorentz transformation cannot in general be formally applied to potentials and fields of particles locked in a certain region. In particular, this property relates to nucleons in nuclei and to particles and nuclei in storage rings. Even if they move with high velocities, their electric fields are defined by the Coulomb law. The result obtained is rather important for the planned deuteron electric-dipole-moment experiment in storage rings.

    ↳ physics.acc-phhep-exhep-phJ.Phys.G(2015)·1 citation
35. 35*

    Fluid dynamic propagation of initial baryon number perturbations on a Bjorken flow background

    Stefan Floerchinger🇨🇭 · Mauricio Martinez🇺🇸

    Baryon number density perturbations offer a possible route to experimentally measure baryon number susceptibilities and heat conductivity of the quark gluon plasma. We study the fluid dynamical evolution of local and event-by-event fluctuations of baryon number density, flow velocity and energy density on top of a (generalized) Bjorken expansion. To that end we use a background-fluctuation splitting and a Bessel-Fourier decomposition for the fluctuating part of the fluid dynamical fields with respect to the azimuthal angle, the radius in the transverse plane and rapidity. We examine how the time evolution of linear perturbations depends on the equation of state as well as on shear viscosity, bulk viscosity and heat conductivity for modes with different azimuthal, radial and rapidity wave numbers. Finally we discuss how this information is accessible to experiments in terms of the transverse and rapidity dependence of correlation functions for baryonic particles in high energy nuclear collisions.

    ↳ nucl-thhep-phPRC(2015)·37 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.