Thu·Jan 26, 2017Thursday·January 26, 2017

1. 01*

   Quartified Leptonic Color, Bound States, and Future Electron-Positron Collider

   Corey Kownacki🇺🇸 · Ernest Ma🇺🇸 · Nicholas Pollard🇺🇸 · Oleg Popov🇺🇸 · Mohammadreza Zakeri🇺🇸

   The $[SU(3){]}^4$ quartification model of Babu, Ma, and Willenbrock (BMW), proposed in 2003, predicts a confining leptonic color $SU(2)$ gauge symmetry, which becomes strong at the keV scale. It also predicts the existence of three families of half-charged leptons (hemions) below the TeV scale. These hemions are confined to form bound states which are not so easy to discover at the Large Hadron Collider (LHC). However, just as $J/\psi$ and ${\rm Y}$ appeared as sharp resonances in $e^{-}{e}^{+}$ colliders of the 20th century, the corresponding 'hemionium' states are expected at a future $e^{-}{e}^{+}$ collider of the 21st century.

   hep-phPLB(2017)·12 citations
2. 02*

   NLO electroweak radiative corrections for four-fermionic process at Belle II

   A. Aleksejevs🇨🇦 · S. Barkanova🇨🇦 · V. Zykunov🇧🇾

   We discuss the next to the leading order (NLO) electroweak radiative corrections to the $e^{-}{e}^{+}\to f^{-}{f}^{+}(\gamma )$ cross section asymmetry, for polarized and unpolarized beam scenario. The left-right and forward-backward amplitudes, with and without radiative corrections, are evaluated and compared for various kinematics. The hard bremsstrahlung is included for arbitrary energy cuts. The radiative corrections are shown to be significant and having a non-trivial dependency on the kinematic conditions. The calculations are relevant for the ultra-precise low-energy experiment Belle~II planned at SuperKEKB.

   hep-phEPJ Web Conf.(2017)·3 citations
3. 03*

   Complete renormalization of QCD at five loops

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

   We present new analytical five-loop Feynman-gauge results for the anomalous dimensions of ghost field and -vertex, generalizing the known values for SU(3) to a general gauge group. Together with previously published results on the quark mass and -field anomalous dimensions and the Beta function, this completes the 5-loop renormalization program of gauge theories in that gauge.

   hep-phhep-thJHEP(2017)·111 citations
4. 04*

   Novel scenario for production of heavy flavored mesons in heavy ion collisions

   B.Z. Kopeliovich🇨🇱 · J. Nemchik🇨🇿 · I.K. Potashnikova🇨🇱 · Ivan Schmidt🇨🇱

   The observed strong suppression of heavy flavored hadrons produced with high $p_T$, is caused by final state interactions with the created dense medium. Vacuum radiation of high-pT heavy quarks ceases at a short time scale, as is confirmed by pQCD calculations and by LEP measurements of the fragmentation functions of heavy quarks. Production of a heavy flavored hadrons in a dense medium is considerably delayed due to prompt breakup of the hadrons by the medium. This causes a strong suppression of the heavy quark yield because of the specific shape of the fragmentation function. The parameter-free description is in a good accord with available data.

   hep-phnucl-thEPJ Web Conf.(2017)·6 citations
5. 05*

   Suppression vs enhancement of heavy quarkonia in pA collisions

   B. Z. Kopeliovich🇨🇱 · Ivan Schmidt🇨🇱 · M. Siddikov🇨🇱

   We describe production of heavy quarkonia in pA collisions within the dipole approach, assuming dominance of the perturbative color-singlet mechanism (CSM) in the $p_T$-integrated cross section. Although accounting for a nonzero heavy $Q$-$\bar{Q}$ separation is a higher twist correction, usually neglected, we found it to be the dominant source of nuclear effects, significantly exceeding the effects of leading twist gluon shadowing and energy loss. Moreover, this contribution turns out to be the most reliably predicted, relying on the precise measurements of the dipole cross section at HERA. The nuclear suppression of quarkonia has been anticipated to become stronger with energy, because the dipole cross section steeply rises. However, the measured nuclear effects remain essentially unchanged within the energy range from RHIC to the LHC. A novel production mechanism is proposed, which enhances the charmonium yield. Nuclear effects for the production of $J/\psi$, $\psi (2S)$, ${\rm Y}(1S)$ and ${\rm Y}(2S)$ are calculated, in agreement with data from RHIC and LHC. The dipole description offers a unique explanation for the observed significant nuclear suppression of $\psi (2S)$ to $J/\psi$ ratio, related to the nontrivial features of the $\psi (2S)$ wave function.

   hep-phPRC(2017)·20 citations
6. 06*

   Spinor helicity methods in high-energy factorization: efficient momentum-space calculations in the Color Glass Condensate formalism

   A. Ayala🇲🇽 · M. Hentschinski🇲🇽 · J. Jalilian-Marian🇺🇸 · M. E. Tejeda-Yeomans🇲🇽

   We use the spinor helicity formalism to calculate the cross section for production of three partons of a given polarization in Deep Inelastic Scattering (DIS) off proton and nucleus targets at small Bjorken x. The target proton or nucleus is treated as a classical color field (shock wave) from which the produced partons scatter multiple times. We reported our result for the final expression for the production cross section and studied the azimuthal angular correlations of the produced partons in [1]. Here we provide the full details of the calculation of the production cross section using the spinor helicity methods.

   hep-phNPB(2017)·41 citations
7. 07*

   Transition form-factor of $\gamma \to 3\pi$ in nonlocal quark model

   A.S. Zhevlakov (Tomsk State University)🇷🇺

   The transition form factor of a gamma into three pions $F_{3\pi }$ are studied in a framework of nonlocal chiral quark model. In local limit the result is agreement with chiral perturbative theory and reproduce Wess-Zumino-Witten anomaly. Availability of nonlocality not change a value of transition form factor in chiral limit. On the physical threshold of reaction, the transition form factor $F_{3\pi }$ is obtained close to the experimental data on account of current mass of quark.

   hep-phPRD(2017)·3 citations
8. 08*

   $K_S^0-K_L^0$ asymmetries in $D$-meson decays

   Di Wang🇨🇳 · Fu-Sheng Yu🇨🇳 · Peng-Fei Guo🇨🇳 · Hua-Yu Jiang🇨🇳

   The $K_S^0-K_L^0$ asymmetries in the $D$ meson decays, induced by the interference between the Cabibbo-favored and the doubly Cabibbo-suppressed amplitudes, can help to understand the dynamics of charm decays. All possible processes of two-body non-leptonic $D$ decays into one neutral kaon and another pseudoscalar or vector meson are considered. We study the $K_S^0-K_L^0$ asymmetries and the branching fractions of corresponding processes in the factorization-assisted topological-amplitude approach in which significant flavor $SU(3)$ symmetry breaking effects are included. The branching fractions of $K_L^0$ modes are predicted. It is first found that the $K_S^0-K_L^0$ asymmetries in the $D^0$-meson decays are shifted by the $D^0-{\overline{D}}^0$ mixing parameter $y_D\simeq 0.006$, to be $0.113\pm 0.001$ for all the relevant $D^0$ decay modes. Our results on $K_S^0-K_L^0$ asymmetries are consistent with the current data and could be tested by experiments in the future.

   hep-phhep-exPRD(2017)·32 citations
9. 09*

   Neutrino Lines from Majoron Dark Matter

   Camilo Garcia-Cely🇧🇪 · Julian Heeck🇧🇪

   Models with spontaneously broken global lepton number can lead to a pseudo-Goldstone boson as a long-lived dark matter candidate. Here we revisit the case of singlet majoron dark matter and discuss multiple constraints. For masses above MeV, this model could lead to a detectable flux of monochromatic mass-eigenstate neutrinos, which have flavor ratios that depend strongly on the neutrino mass hierarchy. We provide a convenient parametrization for the loop-induced majoron couplings to charged fermions that allows us to discuss three-generation effects such as lepton flavor violation. These couplings are independent of the low-energy neutrino parameters but can be constrained by the majoron decays into charged fermions.

   hep-phastro-ph.HEhep-exJHEP(2017)·139 citations
10. 10*

    Flavor analysis of nucleon, $\Delta$, and hyperon electromagnetic form factors

    Martin Rohrmoser🇫🇷 · Ki-Seok Choi🇰🇷 · Willibald Plessas🇦🇹

    By the analysis of the world data base of elastic electron scattering on the proton and the neutron (for the latter, in fact, on ${}^{2}H$ and ${}^{3}He$) important experimental insights have recently been gained into the flavor compositions of nucleon electromagnetic form factors. We report on testing the Graz Goldstone-boson-exchange relativistic constituent-quark model in comparison to the flavor contents in low-energy nucleons, as revealed from electron-scattering phenomenology. It is found that a satisfactory agreement is achieved between theory and experiment for momentum transfers up to $Q^2\sim$ 4 GeV${}^2$, relying on three-quark configurations only. Analogous studies have been extended to the $\Delta$ and the hyperon electromagnetic form factors. For them we here show only some sample results in comparison to data from lattice quantum chromodynamics.

    hep-phnucl-thFew Body Syst.(2017)·1 citation
11. 11*

    Workshop on Excited Hyperons in QCD Thermodynamics at Freeze-Out (YSTAR2016) Mini-Proceedings

    P. Alba · M. Amaryan · V. Begun · R. Bellwied · S. Borsanyi · W. Broniowski · S. Capstick · E. Chudakov · V. Crede · B. Dönigus · R. G. Edwards · Z. Fodor and 29 other authors

    This Workshop brought top experts, researchers, postdocs, and students from high-energy heavy ion interactions, lattice QCD and hadronic physics communities together. YSTAR2016 discussed the impact of "missing" hyperon resonances on QCD thermodynamics, on freeze-out in heavy ion collisions, on the evolution of early universe, and on the spectroscopy of strange particles. Recent studies that compared lattice QCD predictions of thermodynamic properties of quark-gluon plasma at freeze-out with calculations based on statistical hadron resonance gas models as well as experimentally measured ratios between yields of different hadron species in heavy ion collisions provide indirect evidence for the presence of "missing" resonances in all of these contexts. The aim of the YSTAR2016 Workshop was to sharpen these comparisons and advance our understanding of the formation of strange hadrons from quarks and gluons microseconds after the Big Bang and in todays experiments at LHC and RHIC as well as at future facilities like FAIR, J-PARC and KL at JLab. It was concluded that the new initiative to create a secondary beam of neutral kaons at JLab will make a bridge between the hardron spectroscopy, heavy-ion experiments and lattice QCD studies addressing some major issues related to thermodynamics of the early universe and cosmology in general.

    hep-ph9 citations
12. 12*

    Cuts of Feynman Integrals in Baikov representation

    Hjalte Frellesvig🇬🇷 · Costas G. Papadopoulos🇬🇷

    Based on the Baikov representation, we present a systematic approach to compute cuts of Feynman Integrals, appropriately defined in $d$ dimensions. The information provided by these computations may be used to determine the class of functions needed to analytically express the full integrals.

    hep-phhep-thJHEP(2017)·199 citations
13. 13*

    Single inclusive jet transverse momentum and energy spectra at very forward rapidity in proton-proton collisions with $\sqrt{s}=7$ and 13 TeV

    Krzysztof Kutak🇵🇱 · Hans Van Haevermaet🇧🇪 · Pierre Van Mechelen🇧🇪

    We present predictions of single inclusive jet transverse momentum, energy, and Feynman-$x$ spectra at forward rapidity ($5.2<y<6.6$) in proton-proton collisions with $\sqrt{s}=7$ and 13 TeV. Calculations based on high-energy factorization and $k_T$-dependent parton densities are compared to simulations using the \pythia\ event generator. Effects from parton density evolution, parton shower dynamics, multi-parton interactions, and saturation of parton densities are investigated.

    hep-phhep-exPLB(2017)·7 citations
14. 14*

    Polarization effects in light-by-light scattering: Euler-Heisenberg versus Born-Infeld

    A. Rebhan🇦🇹 · G. Turk🇦🇹

    The angular dependence of the differential cross section of unpolarized light-by-light scattering summed over final polarizations is the same in any low-energy effective theory of quantum electrodynamics and also in Born-Infeld electrodynamics. In this paper we derive general expressions for polarization-dependent low-energy scattering amplitudes, including a hypothetical parity-violating situation. These are evaluated for quantum electrodynamics with charged scalar or spinor particles, which give strikingly different polarization effects. Ordinary quantum electrodynamics is found to exhibit rather intricate polarization patterns for linear polarizations, whereas supersymmetric quantum electrodynamics and Born-Infeld electrodynamics give particularly simple forms.

    hep-phphysics.opticsInt.J.Mod.Phys.A(2017)·31 citations
15. 15*

    The 30 GeV Dimuon Excess at ALEPH

    Kenneth Lane🇺🇸 · Lukas Pritchett🇺🇸

    A simple variation of a two-Higgs-doublet model is proposed to describe the $30\mathrm{GeV}$ dimuon excess reported by Heister in his reanalysis of $Z\to \bar{b}b$ events in ALEPH data taken in 1992-95. The heavier CP-even Higgs $H$ is the $125\mathrm{GeV}$ Higgs boson discovered at the LHC. The model admits two options for describing the dimuon excess: (1) The lighter CP-even Higgs $h$ and the CP-odd state ${\eta }_A$ are approximately degenerate and contribute to the $30\mathrm{GeV}$ excess. (2) Only the $h$ is at $30\mathrm{GeV}$ while the ${\eta }_A$ and $H$ are approximately degenerate at $125\mathrm{GeV}$. The ALEPH data favor option 1. Testable predictions are presented for LHC as well as LEP experiments. A potential no-go theorem for models of this type is also discussed.

    hep-phhep-ex5 citations
16. 16*

    Exclusive decays $J/\psi \to D_{(s)}^{(\ast )-}{\ell }^{+}{\nu }_{\ell }$ in a covariant constituent quark model with infrared confinement

    Mikhail A. Ivanov🇷🇺 · Chien-Thang Tran🇷🇺

    We investigate the exclusive semileptonic decays $J/\psi \to D_{(s)}^{(\ast )-}{\ell }^{+}{\nu }_{\ell }$, where $\ell =e,\mu$, within the Standard Model. The relevant transition form factors are calculated in the framework of a relativistic constituent quark model with built-in infrared confinement. Our calculations predict the branching fractions $\mathcal{B}(J/\psi \to D_{(s)}^{(\ast )-}{\ell }^{+}{\nu }_{\ell })$ to be of the order of $10^{-10}$ for $D_s^{(\ast )-}$ and $10^{-11}$ for $D^{(\ast )-}$. Most of our numerical results are consistent with other theoretical studies. However, some branching fractions are larger than those calculated in QCD sum rules approaches but smaller than those obtained in the covariant light-front quark model by a factor of about $2-3$.

    hep-phPRD(2015)·37 citations
17. 17*

    Solution to the evolution equation at NLL for high parton density QCD

    Wenchang Xiang🇨🇳 · Shaohong Cai🇨🇳 · Daicui Zhou🇨🇳

    We analytically solve the full next-to-leading logarithmic Balitsky-Kovchegov equation in the saturation regime, which includes corrections from quark and gluon loops, and large double transverse logarithms. The analytic result for the $S$-matrix in the saturation regime shows that the linear rapidity decrease with rapidity of the exponent in running coupling case is replaced by rapidity raised to power of 3/2 decreasing. The collinearly-improved Balitsky-Kovchegov equation are also analytically solved in the saturation regime. It shows that the double collinear logarithms do not contribute to the $S$-matrix and the solution is the same as the one obtained from the leading order Balitsky-Kovchegov equation. The numerical solutions to the leading order and full next-to-leading logarithmic Balitsky-Kovchegov equations are performed in order to test the analytic results derived in the saturation regime.

    hep-phPRD(2017)·14 citations
18. 18*

    Simplified dark matter models with two Higgs doublets: I. Pseudoscalar mediators

    Martin Bauer🇩🇪 · Ulrich Haisch🇬🇧 · Felix Kahlhoefer🇩🇪

    We study a new class of renormalisable simplified models for dark matter searches at the LHC that are based on two Higgs doublet models with an additional pseudoscalar mediator. In contrast to the spin-0 simplified models employed in analyses of Run I data these models are self-consistent, unitary and bounds from Higgs physics typically pose no constraints. Predictions for various missing transverse energy ($E_{T,\mathrm{miss}}$) searches are discussed and the reach of the 13 TeV LHC is explored. It is found that the proposed models provide a rich spectrum of complementary observables that lead to non-trivial constraints. We emphasise in this context the sensitivity of the $t\bar{t}+E_{T,\mathrm{miss}}$, mono-$Z$ and mono-Higgs channels, which yield stronger limits than mono-jet searches in large parts of the parameter space. Constraints from spin-0 resonance searches, electroweak precision measurements and flavour observables are also derived and shown to provide further important handles to constraint and to test the considered dark matter models.

    hep-phhep-exJHEP(2017)·233 citations
19. 19*

    Muon Beam Experiments to Probe the Dark Sector

    Chien-Yi Chen🇨🇦 · Maxim Pospelov🇨🇦 · Yi-Ming Zhong🇺🇸

    A persistence of several anomalies in muon physics, such as the muon anomalous magnetic moment and the muonic hydrogen Lamb shift, hints at new light particles beyond the Standard Model. We address a subset of these models that have a new light scalar state with sizable couplings to muons and suppressed couplings to electrons. A novel way to search for such particles would be through muon beam-dump experiments by (1) missing momentum searches; (2) searches for decays with displaced vertices. The muon beams available at CERN and Fermilab present attractive opportunities for exploring the new scalar with a mass below the di-muon threshold, and potentially covering a range of relevant candidate models. For the models considered in this paper, both types of signals, muon missing momentum and anomalous energy deposition at a distance, can probe a substantial fraction of the unexplored parameter space of the new light scalar, including a region that can explain the muon anomalous magnetic moment discrepancy.

    hep-phPRD(2017)·117 citations
20. 20*

    Dark Matter and Exotic Neutrino Interactions in Direct Detection Searches

    Enrico Bertuzzo🇧🇷 · Frank F. Deppisch🇬🇧 · Suchita Kulkarni🇦🇹 · Yuber F. Perez Gonzalez🇧🇷 · Renata Zukanovich Funchal🇧🇷

    We investigate the effect of new physics interacting with both Dark Matter (DM) and neutrinos at DM direct detection experiments. Working within a simplified model formalism, we consider vector and scalar mediators to determine the scattering of DM as well as the modified scattering of solar neutrinos off nuclei. Using existing data from LUX as well as the expected sensitivity of LUX-ZEPLIN and DARWIN, we set limits on the couplings of the mediators to quarks, neutrinos and DM. Given the current limits, we also assess the true DM discovery potential of direct detection experiments under the presence of exotic neutrino interactions. In the case of a vector mediator, we show that the DM discovery reach of future experiments is affected for DM masses $m_{\chi }\lesssim 10$ GeV or DM scattering cross sections ${\sigma }_{\chi }\lesssim 10^{-47}$ cm${}^2$. On the other hand, a scalar mediator will not affect the discovery reach appreciably.

    hep-phJHEP(2017)·65 citations
21. 21*

    Power Spectra Based Planck Constraints on Compensated Isocurvature, and Forecasts for LiteBIRD and CORE Space Missions

    Jussi Valiviita🇫🇮

    Compensated isocurvature perturbations (CIP), where the baryon and cold dark matter perturbations cancel, do not cause total matter isocurvature perturbation. Consequently, at the linear order in the baryon density contrast $\Delta$, CIP is not detectable by the CMB power spectra. At the second order CIP smoothes the power spectra in a similar manner as lensing, causing a degeneracy between the CIP variance ${\Delta }_{rms}^2=<{\Delta }^2>$ and lensing parameter $A_L$. We show that the CMB lensing data breaks this degeneracy. Nested sampling of the LCDM+CIP(+$A_L$) model, the Planck 2015 temperature, polarization, and lensing data give ${\Delta }_{rms}^2=0.0069\pm 0.0030$ at 68% CL. A non-zero value is favored at 2.3$\sigma$. CIP with ${\Delta }_{rms}^2=0.007$ improves the bestfit ${\chi }^2$ by 3.6 compared to the adiabatic LCDM model. In contrast, although the temperature data favor $A_L=1.22$, allowing $A_L\ne 1$ does not improve the joint fit, since the lensing data disfavor $A_L\ne 1$. Indeed, CIP provides a rare example of a simple model, which can reduce the Planck lensing anomaly by fitting well simultaneously the high multipole temperature and lensing data, as well as the polarization data. Finally, we derive forecasts for future satellite missions (LiteBIRD proposal to JAXA and Exploring Cosmic Origins with CORE proposal to ESA's M5 call). Due to its coarse angular resolution, LiteBIRD is not able to improve the constraints on CIP or $A_L$, but CORE-M5 approaches the cosmic variance limit and improves the CIP constraint to ${\Delta }_{rms}^2<0.0006(0.0014)$ at 68% (95%) CL, which is 9 times better than the current trispectrum based upper bound and 6 times better than obtained from the simulated Planck data. In addition, CORE-M5 will exquisitely distinguish between CIP and $A_L$. No matter whether CIP is allowed for or not, the uncertainty of the lensing parameter will be $\sigma (A_L)=0.012$.

    ↳ astro-ph.COhep-phJCAP(2017)·31 citations
22. 22*

    Causality and Unitarity via the Tree-Loop Duality Relation

    E. T. Tomboulis🇺🇸

    The tree-loop duality relation is used as a starting point to derive the constraints of causality and unitarity. Specifically, the Bogoliubov causality condition is ab initio derived at the individual graph level. It leads to a representation of a graph in terms of lower order cut graphs. Extracting the absorptive part gives then the general unitarity relation (Cutkosky rule). The derivation, being carried out directly in momentum space, holds for any local (polynomial) hermitian interaction vertices. This is in contrast to the technical difficulties arising from contact terms in the spacetime approach based on the largest time equation.

    ↳ hep-thhep-phJHEP(2017)·54 citations
23. 23*

    On the knee of Galactic cosmic rays in light of sub-TeV spectral hardenings

    Yi-Qing Guo🇨🇳 · Qiang Yuan🇨🇳

    More than fifty years after the discovery of the knee in the cosmic ray spectra, its physical origin remains a mystery. This is partly due to the ambiguity of the energy spectrum of individual composition. Recently, direct measurements from several balloon/satellite-borne detectors found significant spectral hardenings of cosmic ray nuclei at a few hundred GV rigidities. A joint modeling of the direct and indirect measurements of the cosmic ray spectra may help to understand the experimental systematics and probably the physics of the knee. In this work, we update the phenomenological "poly-gonato" model of the knee to include the spectral hardenings, with a changing spectral index of $\gamma +\beta \cdot \log E$ with respect to energy. We find that there is some tension between the direct and indirect measurements. Specifically, the hard spectra of CREAM suggest a relatively low energy cutoff of the individual cosmic ray spectrum around the knee, which is inconsistent with the light component spectra of the air shower measurements. Furthermore, the light component data from AS$\gamma$/ARGO-YBJ/WFCTA/KASCADE are consistent with the all-particle spectra. We expect that more precise measurements of the cosmic ray spectrum of individual composition at TeV energies and beyond by the operating space detectors such as CALET and DAMPE, and the ground based experiments such as LHAASO, will eventually solve these discrepancies. Finally, as an illustration, we show that a spatial-dependent diffusion under two-halo model is able to reproduce the results of this "modified poly-gonato" model.

    ↳ astro-ph.HEhep-phCPC(2018)·18 citations
24. 24*

    Northern sky Galactic Cosmic Ray anisotropy between 10-1000 TeV with the Tibet Air Shower Array

    Tibet AS-gamma Collaboration · M. Amenomori

    We report the analysis of the $10-1000$ TeV large-scale sidereal anisotropy of Galactic cosmic rays (GCRs) with the data collected by the Tibet Air Shower Array from October, 1995 to February, 2010. In this analysis, we improve the energy estimate and extend the declination range down to $-30^{\circ }$. We find that the anisotropy maps above 100 TeV are distinct from that at multi-TeV band. The so-called "tail-in" and "loss-cone" features identified at low energies get less significant and a new component appears at $\sim 100$ TeV. The spatial distribution of the GCR intensity with an excess (7.2$\sigma$ pre-trial, 5.2$\sigma$ post-trial) and a deficit ($-5.8\sigma$ pre-trial) are observed in the 300 TeV anisotropy map, in a good agreement with IceCube's results at 400 TeV. Combining the Tibet results in the northern sky with IceCube's results in the southern sky, we establish a full-sky picture of the anisotropy in hundreds of TeV band. We further find that the amplitude of the first order anisotropy increases sharply above $\sim 100$ TeV, indicating a new component of the anisotropy. All these results may shed new light on understanding the origin and propagation of GCRs.

    ↳ astro-ph.HEhep-phApJ(2017)·118 citations
25. 25*

    One fluid to rule them all: viscous hydrodynamic description of event-by-event central p+p, p+Pb and Pb+Pb collisions at $\sqrt{s}=5.02$ TeV

    Ryan D. Weller🇺🇸 · Paul Romatschke🇺🇸

    The matter created in central p+p, p+Pb and Pb+Pb collisions at sqrt{s}=5.02 TeV is simulated event-by-event using the superSONIC model, which combines pre-equilibrium flow, viscous hydrodynamic evolution and late-stage hadronic rescatterings. Employing a generalization of the Monte Carlo Glauber model where each nucleon possesses three constituent quarks, superSONIC describes the experimentally measured elliptic and triangular flow at central rapidity in all systems using a single choice for the fluid parameters, such as shear and bulk viscosities. This suggests a common hydrodynamic origin of the experimentally observed flow patterns in all high energy nuclear collisions, including p+p.

    ↳ nucl-thhep-phnucl-exPLB(2017)·309 citations
26. 26*

    The effects of the small-scale behaviour of dark matter power spectrum on CMB spectral distortion

    Abir Sarkar🇮🇳 · Shiv K. Sethi🇮🇳 · Subinoy Das🇮🇳

    After numerous astronomical and experimental searches, the precise particle nature of dark matter is still unknown. The standard Weakly Interacting Massive Particle(WIMP) dark matter, despite successfully explaining the large-scale features of the universe, has long-standing small-scale issues. The spectral distortion in the Cosmic Microwave Background(CMB) caused by Silk damping in the pre-recombination era allows one to access information on a range of small scales $0.3\mathrm{Mpc}<k<10^4\mathrm{Mp}{\mathrm{c}}^{-1}$, whose dynamics can be precisely described using linear theory. In this paper, we investigate the possibility of using the Silk damping induced CMB spectral distortion as a probe of the small-scale power. We consider four suggested alternative dark matter candidates---Warm Dark Matter (WDM), Late Forming Dark Matter, Ultra Light Axion dark matter and Charged Decaying Dark Matter; the matter power in all these models deviate significantly from the $\Lambda$CDM model at small scales. We compute the spectral distortion of CMB for these alternative models and compare our results with the $\Lambda$CDM model. We show that the main impact of alternative models is to alter the sub-horizon evolution of the Newtonian potential which affects the late-time behaviour of spectral distortion of CMB. The $y$-parameter diminishes by a few percent as compared to the $\Lambda$CDM model for a range of parameters of these models: LFDM for formation redshift $z_f=10^5$ (7\%); WDM for mass $m_{\mathrm{wdm}}=1\mathrm{keV}$ (2\%); CHDM for decay redshift $z_{\mathrm{decay}}=10^5$ (5\%); ULA for mass $m_a=10^{-24}\mathrm{eV}$ (3\%). We also briefly discuss the detectability of this deviation in light of the upcoming CMB experiment PIXIE, which might have the sensitivity to detect this signal from the pre-recombination phase.

    ↳ astro-ph.COhep-phJCAP(2017)·18 citations
27. 27*

    Refining the detection of the zero crossing for the symmetric and asymmetric three-gluon vertices

    Ph. Boucaud🇫🇷 · F. De Soto🇪🇸 · J. Rodríguez-Quintero🇪🇸 · S. Zafeiropoulos🇺🇸

    This article reports on the detailed study of the three-gluon vertex in four-dimensional $SU(3)$ Yang-Mills theory employing lattice simulations with large physical volumes and high statistics. A meticulous scrutiny of the so-called symmetric and asymmetric kinematical configurations is performed and it is shown that the associated form-factor changes sign at a given range of momenta. The lattice results are compared to the model independent predictions of Schwinger-Dyson equations and a very good agreement among the two is found.

    ↳ hep-lathep-phPRD(2017)·78 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.