Thu·Dec 1, 2016Thursday·December 1, 2016

1. 01*

   Radiatively generated hierarchy of lepton and quark masses

   A. E. Cárcamo Hernández🇨🇱 · Sergey Kovalenko🇨🇱 · Ivan Schmidt🇨🇱

   We propose a model for radiatively generating the hierarchy of the Standard Model (SM) fermion masses: tree-level top quark mass; 1-loop bottom, charm, tau and muon masses; 2-loop masses for the light up, down and strange quarks as well as for the electron; and 4-loop masses for the light active neutrinos. Our model is based on a softly-broken $S_3\times Z_2$ discrete symmetry. Its scalar sector consists only of one SM Higgs doublet and three electrically neutral SM-singlet scalars. We do not need to invoke either electrically charged scalar fields, or an extra $S{U}_{2L}$ scalar doublet, or the spontaneous breaking of the discrete group, which are typical for other radiative models in the literature. The model features a viable scalar dark matter candidate.

   hep-phJHEP(2017)·42 citations
2. 02*

   Scalar and higher even spin glueball masses from an anomalous modified holographic model

   Diego M. Rodrigues🇧🇷 · Eduardo Folco Capossoli🇧🇷 · Henrique Boschi-Filho🇧🇷

   In this work, within an anomalous modified holographic softwall model, we calculate analytically the masses of the scalar glueball with its radial excitations and higher even glueball spin states, with $P=C=+1$, from a single mass equation. Using this approach we achieved an unified treatment for both scalar and high even spin glueballs masses. Furthermore, we also obtain the Regge trajectory associated with the pomeron compatible with other approaches.

   hep-phhep-thEPL(2018)·25 citations
3. 03*

   Revisiting radiative decays of $1^{+-}$ heavy quarkonia in the covariant light-front approach

   Yan-Liang Shi🇺🇸

   We revisit the calculation of the width for the radiative decay of a $1^{+-}$ heavy $Q\bar{Q}$ meson via the channel $1^{+-}\to 0^{-+}+\gamma$ in the covariant light-front quark model. We carry out the reduction of the light-front amplitude in the non-relativistic limit, explicitly computing the leading and next-to-leading order relativistic corrections. This shows the consistency of the light-front approach with the non-relativistic formula for this electric dipole transition. Furthermore, the theoretical uncertainty in the predicted width is studied as a function of the inputs for the heavy quark mass and wavefunction structure parameter. We analyze the specific decays $h_c(1P)\to {\eta }_c(1S)+\gamma$ and $h_b(1P)\to {\eta }_b(1S)+\gamma$. We compare our results with experimental data and with other theoretical predictions from calculations based on non-relativistic models and their extensions to include relativistic effects, finding reasonable agreement.

   hep-phEPJC(2017)·8 citations
4. 04*

   Determining the CP nature of spin-0 mediators in associated production of dark matter and $t\bar{t}$ pairs

   Ulrich Haisch🇬🇧 · Priscilla Pani🇸🇪 · Giacomo Polesello🇮🇹

   In the framework of spin-0 $s$-channel simplified models, we explore the possibility of assessing the structure of dark matter interactions through the associate production of dark matter and $t\bar{t}$ pairs. To this purpose, final states with two leptons are considered and the kinematic properties of the dilepton system is studied. We develop a realistic analysis strategy and provide a detailed evaluation of the achievable sensitivity for the dark matter signal assuming integrated luminosities of $300{\mathrm{fb}}^{-1}$ and $3{\mathrm{ab}}^{-1}$ at the 14 TeV LHC. Furthermore, upper limits on the mediator masses for which the two different CP hypotheses can be distinguished are derived. The obtained limits on the signal strengths are finally translated into constraints on the parameter space of two spin-0 simplified models including a scenario with an extended Higgs sector.

   hep-phhep-exJHEP(2017)·61 citations
5. 05*

   Mott-hadron resonance gas and lattice QCD thermodynamics

   D. Blaschke🇷🇺 · A. Dubinin🇵🇱 · L. Turko🇵🇱

   A unified equation of state for quark-hadron matter is presented in the generalized Beth-Uhlenbeck form. It follows from a $\Phi -$derivable approach to the thermodynamic potential where the ansatz for the $\Phi$ functional contains all 2PI diagrams at two-loop order formed with quark cluster Green's functions for quark, diquark, meson and baryon propagators. We present numerical results using an effective model for the generic behaviour of hadron masses and phase shifts at finite temperature which shares basic features with recent developments within the PNJL model for correlations in quark matter. We obtain the transition between a hadron resonance gas phase and the quark gluon plasma where the Mott dissociation of hadrons is encoded in the hadronic phase shifts. The resulting thermodynamics is in very good agreement with recent lattice QCD simulations.

   hep-phnucl-th8 citations
6. 06*

   The photo-philic QCD axion

   Marco Farina🇺🇸 · Duccio Pappadopulo🇺🇸 · Fabrizio Rompineve🇩🇪 · Andrea Tesi🇺🇸

   We propose a framework in which the QCD axion has an exponentially large coupling to photons, relying on the "clockwork" mechanism. We discuss the impact of present and future axion experiments on the parameter space of the model. In addition to the axion, the model predicts a large number of pseudo-scalars which can be light and observable at the LHC. In the most favorable scenario, axion Dark Matter will give a signal in multiple axion detection experiments and the pseudo-scalars will be discovered at the LHC, allowing to determine most of the parameters of the model.

   hep-phastro-ph.COJHEP(2017)·180 citations
7. 07*

   CheckMATE 2: From the model to the limit

   Daniel Dercks🇩🇪 · Nishita Desai🇫🇷 · Jong Soo Kim🇪🇸 · Krzysztof Rolbiecki🇵🇱 · Jamie Tattersall🇩🇪 · Torsten Weber🇩🇪

   We present the latest developments to the CheckMATE program that allows models of new physics to be easily tested against the recent LHC data. To achieve this goal, the core of CheckMATE now contains over 60 LHC analyses of which 12 are from the 13 TeV run. The main new feature is that CheckMATE 2 now integrates the Monte Carlo event generation via Madgraph and Pythia 8. This allows users to go directly from a SLHA file or UFO model to the result of whether a model is allowed or not. In addition, the integration of the event generation leads to a significant increase in the speed of the program. Many other improvements have also been made, including the possibility to now combine signal regions to give a total likelihood for a model.

   hep-phComput.Phys.Commun.(2017)·315 citations
8. 08*

   Boosted Dark Matter at the Deep Underground Neutrino Experiment

   Haider Alhazmi🇺🇸 · Kyoungchul Kong🇺🇸 · Gopolang Mohlabeng🇺🇸 · Jong-Chul Park🇰🇷

   We investigate the detection prospects of a non-standard dark sector in the context of boosted dark matter. We consider a scenario where two stable particles have a large mass difference and the heavier particle accounts for most of dark matter in our current universe. The heavier candidate is assumed to have no interaction with the standard model particles at tree-level, hence evading existing constraints. Although subdominant, the lighter dark matter particles are efficiently produced via pair-annihilation of the heavier ones in the center of the Galaxy or the Sun. The large Lorentz boost enables detection of the non-minimal dark sector in large volume terrestrial experiments via exchange of a light dark photon with electrons or nuclei. Various experiments designed for neutrino physics and proton decay are examined in detail, including Super-K and Hyper-K. In this study, we focus on the sensitivity of the far detector at the Deep Underground Neutrino Experiment for boosted dark matter produced in the center of the Sun, and compare our findings with recent results for boosted dark matter produced in the galactic center.

   hep-phJHEP(2017)·58 citations
9. 09*

   Exploring the nearly degenerate stop region with sbottom decays

   Haipeng An🇺🇸 · Jiayin Gu🇨🇳 · Lian-Tao Wang🇺🇸

   A light stop with mass almost degenerate with the lightest neutralino has important connections with both naturalness and dark matter relic abundance. This region is also very hard to probe at colliders. In this paper, we demonstrate the potential of searching for such stop particles at the LHC from sbottom decays, focusing on two channels with final states $2\ell +E_{\mathrm{T}}^{\mathrm{miss}}$ and $1b1\ell +E_{\mathrm{T}}^{\mathrm{miss}}$. We found that, if the lightest sbottom has mass around or below 1 TeV and has a significant branching ratio to decay to stop and $W$ ($\tilde{b}\to \tilde{t}W$), a stop almost degenerate with neutralino can be excluded up to about 500-600 GeV at the 13 TeV LHC with $300{\mathrm{fb}}^{-1}$ data. The searches we propose are complementary to other SUSY searches at the LHC and could have the best sensitivity to the stop-bino coannihilation region. Since they involve final states which have already been used in LHC searches, a reinterpretation of the search results already has sensitivity. Further optimization could deliver the full potential of these channels.

   hep-phhep-exJHEP(2017)·9 citations
10. 10*

    Odd Azimuthal Anisotropy of the Glasma for pA Scattering

    Larry McLerran🇺🇸 · Vladimir Skokov🇺🇸

    In this paper we analytically extract the odd azimuthal anisotropy in the Classical Yang-Mills equations for the Glasma for pA collisions. We compute the first non-trivial term in the expansion of the proton sources of color charge. The computation is valid in the limit of a large nucleus when the produced particle momenta are larger than the saturation momentum of the proton.

    hep-phNPA(2017)·45 citations
11. 11*

    The $Z$ decay width in the SMEFT: $y_t$ and $\lambda$ corrections at one loop

    Christine Hartmann🇩🇰 · William Shepherd🇩🇪 · Michael Trott🇩🇰

    We calculate one loop $y_t$ and $\lambda$ dependent corrections to ${\bar{\Gamma }}_Z,{\bar{R}}_f^0$ and the partial $Z$ widths due to dimension six operators in the Standard Model Effective Field Theory (SMEFT), including finite terms. We assume $\mathrm{CP}$ symmetry and a $\mathrm{U}(3{)}^5$ symmetry in the UV matching onto the dimension six operators, dominantly broken by the Standard Model Yukawa matrices. Corrections to these observables are predicted using the input parameters $\{{\hat{\alpha }}_{ew},{\hat{M}}_Z,{\hat{G}}_F,{\hat{m}}_t,{\hat{m}}_h\}$ extracted with one loop corrections in the same limit. We show that at one loop the number of SMEFT parameters contributing to the precise LEPI pseudo-observables exceeds the number of measurements. As a result the SMEFT parameters contributing to LEP data are formally unbounded when the size of loop corrections are reached until other data is considered in a global analysis. The size of these loop effects is generically a correction of order $\sim \%$ to leading effects in the SMEFT, but we find multiple large numerical coefficients in our calculation at this order. We use a $\overline{\mathrm{MS}}$ scheme, modified for the SMEFT, for renormalization. Some subtleties involving novel evanescent scheme dependence present in this result are explained.

    hep-phJHEP(2017)·66 citations
12. 12*

    On the Validity of Dark Matter Effective Theory

    Martin Bauer🇩🇪 · Anja Butter🇩🇪 · Nishita Desai🇫🇷 · Juan Gonzalez-Fraile🇩🇪 · Tilman Plehn🇩🇪

    An effective theory of dark matter offers an attractive framework for global analyses of dark matter. In the light of global fits we test the validity of the link between the non-relativistic dark matter annihilation, or the predicted relic density, and LHC signatures. Specifically, we study how well the effective theory describes the main features of simple models with s-channel and t-channel mediators coupling to the Standard Model at tree level or through one-loop diagrams. Our results indicate that global dark matter analyses in terms of effective Lagrangians are highly non-trivial to interpret in term of actual models.

    hep-phPRD(2017)·26 citations
13. 13*

    Nucleon spin-averaged forward virtual Compton tensor at large $Q^2$

    Richard J. Hill🇺🇸 · Gil Paz🇺🇸

    The nucleon spin-averaged forward virtual Compton tensor determines important physical quantities such as electromagnetically-induced mass differences of nucleons, and two-photon exchange contributions in hydrogen spectroscopy. It depends on two kinematic variables: $\nu$, the virtual photon energy in the proton rest frame, and $Q^2$, the photon's invariant four-momentum squared. Using the operator product expansion, we calculate the tensor's large-$Q^2$ behavior for $\nu =0$, including for the first time the full spin-2 contribution and correcting a previous result in the literature for the spin-0 contribution. Implications for the proton radius puzzle are discussed.

    hep-phnucl-thPRD(2017)·45 citations
14. 14*

    QCD string in excited heavy-light mesons and heavy-quark hybrids

    Yu.S. Kalashnikova🇷🇺 · A.V. Nefediev🇷🇺

    The QCD string model is employed to evaluate the masses of orbitally and radially excited heavy-light mesons and lightest hybrids in the spectrum of charmonium and bottomonium. The number of parameters of the model is reduced to only seven which are the string tension, the two values of the strong coupling constant (one for heavy-light and $\bar{c}c$ mesons and one for $\bar{b}b$ mesons), and the four overall spectrum shift constants which depend on the quark contents of the particular meson or hybrid family. A few well-established states in the spectrum of heavy-light and heavy-heavy mesons are used to fix these parameters, and then the masses of other mesons and hybrids come out as predictions of the model which are confronted with the existing experimental data, and a few suggestions are made concerning yet not measured quantum numbers of some states in the spectrum of charmonium and bottomonium.

    hep-phhep-exhep-latPRD(2016)·9 citations
15. 15*

    Dispersive analysis of the $S$-, $P$-, $D$-, and $F$-wave $\pi \pi$ amplitudes

    P. Bydžovský🇨🇿 · R. Kamiński🇵🇱 · V. Nazari🇵🇱

    A reanalysis of $\pi \pi$ amplitudes for all important partial-waves below about 2 GeV is presented. A set of once subtracted dispersion relations with imposed crossing symmetry condition is used to modify unitary multi-channel amplitudes in the $S$, $P$, $D$, and $F$ waves. So far, these specific amplitudes constructed in our works and many other analyzes have been fitted only to experimental data and therefore do not fulfill the crossing symmetry condition. In the present analysis, the self consistent, i.e. unitary and fulfilling the crossing symmetry, amplitudes for the $S$, $P$, $D$, and $F$ waves are formed. The proposed very effective and simple method of modification of the $\pi \pi$ amplitudes does not change their previous-original mathematical structure and the method can be easily applied in various other analyzes.

    hep-phnucl-thPRD(2016)·25 citations
16. 16*

    Dipole model analysis of highest precision HERA data, including very low $Q^2$'s

    Agnieszka Luszczak🇵🇱 · Henri Kowalski🇩🇪

    We analyse, within a dipole model, the final, inclusive HERA DIS cross section data in the low $x$ region, using fully correlated errors. We show, that these highest precision data are very well described within the dipole model framework starting from $Q^2$ values of 3.5 GeV${}^2$ to the highest values of $Q^2=$ 250 GeV${}^2$.

    hep-phPRD(2017)·26 citations
17. 17*

    More about the light baryon spectrum

    Gernot Eichmann🇩🇪

    We discuss the light baryon spectrum obtained from a recent quark-diquark calculation, implementing non-pointlike diquarks that are self-consistently calculated from their Bethe-Salpeter equations. We examine the orbital angular momentum content in the baryons' rest frame and highlight the fact that baryons carry all possible values of L compatible with their spin, without the restriction P=(-1)^L which is only valid nonrelativistically. We furthermore investigate the meaning of complex conjugate eigenvalues of Bethe-Salpeter equations, their possible connection with 'anomalous' states, and we propose a method to eliminate them from the spectrum.

    hep-phnucl-thFew Body Syst.(2017)·23 citations
18. 18*

    Photon emissivity in the vicinity of a critical point - A case study within the quark meson model

    Falk Wunderlich🇩🇪 · Burkhard Kampfer🇩🇪

    The quark meson (linear sigma) model with linearized fluctuations displays at a critical end point the onset of a curve of first-order phase transitions (FOPTs) located at non-zero chemical potentials and temperatures below a certain cross-over temperature. The model qualifies well for an illustrative example to study the impact of the emerging FOPT, e.g. on photon emissivities. Such a case study unravels the tight interlocking of the phase structure with the emission rates, here calculated according to lowest-order tree level processes by kinetic theory expressions. It is the strong dependence of the rates on the effective masses of the involved degrees of freedom which distinctively vary over the phase diagram thus shaping the emissivity accordingly. At the same time, thermodynamic properties of the medium are linked decisively to these effective masses, i.e. a consistent evaluation of thermodynamics, governing for instance adiabatic expansion paths, and emission rates is maintained within such an approach.

    hep-phNPA(2017)·2 citations
19. 19*

    Prompt charmonia production and polarization at LHC in the NRQCD with $k_T$-factorization. Part III: $J/\psi$ meson

    S.P. Baranov🇷🇺 · A.V. Lipatov🇷🇺

    In the framework of $k_T$-factorization approach, the production and polarization of prompt $J/\psi$ mesons at the LHC energies is studied. Our consideration is based on the non-relativistic QCD formalism for bound states and off-shell amplitudes for hard partonic subprocesses. Both the direct production mechanism and feed-down contributions from ${\chi }_c$ and $\psi (2S)$ decays are taken into account. The transverse momentum dependent (or unintegrated) gluon densities in a proton were derived from Ciafaloni-Catani-Fiorani-Marchesini evolution equation or, alternatively, were chosen in accordance with Kimber-Martin-Ryskin prescription. The non-perturbative color-octet matrix elements were first deduced from the fits to the latest CMS data on $J/\psi$ transverse momentum distributions and then applied to describe the ATLAS and LHCb data on $J/\psi$ production and polarization at $\sqrt{s}=7$, $8$ and $13$ TeV. We perform an estimation of polarization parameters ${\lambda }_{\theta }$, ${\lambda }_{\varphi }$ and ${\lambda }_{\theta \varphi }$ which determine $J/\psi$ spin density matrix and demonstrate that treating the soft gluon emission as a series of explicit color-electric dipole transitions within NRQCD leads to unpolarized $J/\psi$ production at high transverse momenta, that is in qualitative agreement with the LHC data.

    hep-phPRD(2017)·29 citations
20. 20*

    Event patterns extracted from top quark-related spectra in proton-proton collisions at 8 TeV

    Ya-Hui Chen🇨🇳 · Fu-Hu Liu🇨🇳 · Roy A. Lacey🇺🇸

    We analyze the transverse momentum ($p_T$) and rapidity ($y$) spectra of top quark pairs, hadronic top quarks, and top quarks produced in proton-proton ($pp$) collisions at center-of-mass energy $\sqrt{s}=8$ TeV. For $p_T$ spectra, we use the superposition of the inverse power-law suggested by the QCD (quantum chromodynamics) calculus and the Erlang distribution resulting from a multisource thermal model. For $y$ spectra, we use the two-component Gaussian function resulting from the revised Landau hydrodynamic model. The modelling results are in agreement with the experimental data measured at the detector level, in the fiducial phase-space, and in the full phase-space by the ATLAS Collaboration at the Large Hadron Collider (LHC). Based on the parameter values extracted from $p_T$ and $y$ spectra, the event patterns in three-dimensional velocity (${\beta }_x$-${\beta }_y$-${\beta }_z$), momentum ($p_x$-$p_y$-$p_z$), and rapidity ($y_1$-$y_2$-$y$) spaces are obtained, and the probability distributions of these components are also obtained.

    hep-phhep-exnucl-exnucl-thCPC(2018)·2 citations
21. 21*

    Top and Electroweak bosons and Higgs

    Eleni Vryonidou🇧🇪

    I review recent progress in the computation of processes involving top quarks in the framework of Standard Model Effective Theory at NLO in QCD. In particular I discuss the impact of higher-dimensional operators on top pair production in association with a photon, a Z boson and a Higgs. Results are obtained within the automated framework of MadGraph5_aMC@NLO.

    hep-ph0 citations
22. 22*

    Non-Minimal Quartic Inflation in Supersymmetric SO(10)

    George K. Leontaris🇬🇷 · Nobuchika Okada🇺🇸 · Qaisar Shafi🇺🇸

    We describe how quartic ($\lambda {\varphi }^4$) inflation with non-minimal coupling to gravity is realized in realistic supersymmetric $SO(10)$ models. In a well-motivated example the $16-\overline{16}$ Higgs multiplets, which break $SO(10)$ to $SU(5)$ and yield masses for the right-handed neutrinos, provide the inflaton field $\varphi$. Thus, leptogenesis is a natural outcome in this class of $SO(10)$ models. Moreover, the adjoint (45-plet) Higgs also acquires a GUT scale value during inflation so that the monopole problem is evaded. The scalar spectral index $n_s$ is in good agreement with the observations and $r$, the tensor to scalar ratio, is predicted for realistic values of GUT parameters to be of order $10^{-3}-10^{-2}$.

    hep-phhep-thPLB(2017)·17 citations
23. 23*

    Mesons in ultra-intense magnetic field: an evaded collapse

    B.O. Kerbikov🇷🇺 · M.A. Andreichikov🇷🇺 · Yu.A. Simonov🇷🇺

    Spectra of $q\bar{q}$ mesons are investigated in the framework of the Hamiltonian obtained from the relativistic path integral in external homogeneous magnetic field. The spectra of all 12 spin-isospin s-wave states generated by $\pi$- and $\rho$-mesons with different spin projections, are studied analytically as functions of the field strength. Three types of behavior with characteristic splittings are found. The results are in agreement with recent lattice calculations.

    hep-phEPJ Web Conf.(2017)·0 citations
24. 24*

    Sizes and Distances in High Energy Physics

    V.A. Petrov🇷🇺

    This is a critical discussion of physical relevance of some space-time characteristics which are in current use in high energy physics.

    hep-phEPJ Web Conf.(2017)·7 citations
25. 25*

    Integrating out resonances in strongly-coupled electroweak scenarios

    Ignasi Rosell🇪🇸 · Antonio Pich🇪🇸 · Joaquin Santos🇪🇸 · Juan Jose Sanz-Cillero🇪🇸

    Accepting that there is a mass gap above the electroweak scale, the Electroweak Effective Theory (EWET) is an appropriate tool to describe this situation. Since the EWET couplings contain information on the unknown high-energy dynamics, we consider a generic strongly-coupled scenario of electroweak symmetry breaking, where the known particle fields are coupled to heavier states. Then, and by integrating out these heavy fields, we study the tracks of the lightest resonances into the couplings. The determination of the low-energy couplings (LECs) in terms of resonance parameters can be made more precise by considering a proper short-distance behaviour on the Lagrangian with heavy states, since the number of resonance couplings is then reduced. Notice that we adopt a generic non-linear realization of the electroweak symmetry breaking with a singlet Higgs.

    hep-phEPJ Web Conf.(2017)·2 citations
26. 26*

    J/psi+Z production at the LHC

    Jean-Philippe Lansberg🇫🇷 · Hua-Sheng Shao🇨🇭

    We briefly review recent results which we have obtained in the study of J/psi+Z production at the LHC. Considering our NLO computation in the Colour Evaporation Model (CEM) as an upper theory limit for the single-parton-scattering contributions, we claim that the existing data set from ATLAS points at a dominant double-parton-scattering contribution with an effective cross section smaller than that for jet-related observables. As a side product of our analysis, we have computed, for the first time, the one-loop QCD corrections to the J/psi P_T-differential cross section in the CEM.

    hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2017)·1 citation
27. 27*

    Yang--Mills Glueballs as Closed Bosonic Strings

    Sergei Dubovsky🇺🇸 · Guzman Hernandez-Chifflet🇺🇸

    We put forward the Axionic String Ansatz (ASA), which provides a unified description for the worldsheet dynamics of confining strings in pure Yang--Mills theory both in $D=3$ and $D=4$ space-time dimensions. The ASA is motivated by the excitation spectrum of long confining strings, as measured on a lattice, and by recently constructed integrable axionic non-critical string models. According to the ASA, pure gluodynamics in 3D is described by a non-critical bosonic string theory without any extra local worldsheet degrees of freedom. We argue that this assumption fixes the set of quantum numbers (spins, $P$- and $C$-parities) of almost all glueball states. We confront the resulting predictions with the properties of approximately $1^2+2^2+3^2+5^2=39$ lightest glueball states measured on a lattice and find a good agreement. On the other hand, the spectrum of low lying glueballs in 4D gluodynamics suggests the presence of a massive pseudoscalar mode on the string worldsheet, in agreement with the ASA and lattice data for long strings.

    ↳ hep-thhep-lathep-phJHEP(2017)·29 citations
28. 28*

    Emergent phenomena and partonic structure in hadrons

    Craig D. Roberts🇺🇸 · Cedric Mezrag🇺🇸

    Modern facilities are poised to tackle fundamental questions within the Standard Model, aiming to reveal the nature of confinement, its relationship to dynamical chiral symmetry breaking (DCSB) - the origin of visible mass - and the connection between these two, key emergent phenomena. There is strong evidence to suggest that they are intimately connected with the appearance of momentum-dependent masses for gluons and quarks in QCD, which are large in the infrared: $m_g\sim 500$MeV and $M_q\sim 350$MeV. DCSB, expressed in the dynamical generation of a dressed-quark mass, has an enormous variety of verifiable consequences, including an enigmatic result that the properties of the (almost) massless pion are the cleanest expression of the mechanism which is responsible for almost all the visible mass in the Universe. This contribution explains that these emergent phenomena are expressed with particular force in the partonic structure of hadrons, e.g. in valence-quark parton distribution amplitudes and functions, and, consequently, in numerous hadronic observables, so that we are now in a position to exhibit the consequences of confinement and DCSB in a wide range of hadron observables, opening the way to empirical verification of their expression in the Standard Model.

    ↳ nucl-thhep-lathep-phnucl-exEPJ Web Conf.(2017)·7 citations
29. 29*

    Searches for correlation between UHECR events and high-energy gamma-ray Fermi-LAT data

    Ezequiel Alvarez🇦🇷 · Alessandro Cuoco🇩🇪 · Nestor Mirabal🇺🇸 · Gabrijela Zaharijas🇸🇮

    The astrophysical sources responsible for ultra high-energy cosmic rays (UHECRs) continue to be one of the most intriguing mysteries in astrophysics. We present a comprehensive search for correlations between high-energy ($⪆1$ GeV) gamma-ray events from the Fermi Large Area Telescope (LAT) and UHECRs ($⪆60$ EeV) detected by the Telescope Array and the Pierre Auger Observatory. We perform two separate searches. First, we conduct a standard cross-correlation analysis between the arrival directions of 148 UHECRs and 360 gamma-ray sources in the Second Catalog of Hard Fermi-LAT sources (2FHL). Second, we search for a possible correlation between UHECR directions and unresolved Fermi-LAT gamma-ray emission. For the latter, we use three different methods: a stacking technique with both a model-dependent and model-independent background estimate, and a cross-correlation function analysis. We also test for statistically significant excesses in gamma rays from signal regions centered on Cen A and the Telescope Array hotspot. No significant correlation is found in any of the analyses performed, except a weak ($⪅2\sigma$) hint of signal with the correlation function method on scales $\sim 1^{\circ }$. Upper limits on the flux of possible power-law gamma-ray sources of UHECRs are derived.

    ↳ astro-ph.HEhep-phJCAP(2016)·9 citations
30. 30*

    Scale-Chiral Symmetry, Proton Mass and Sound Velocity in Compact-Star Matter

    Won-Gi Paeng🇰🇷 · Mannque Rho🇫🇷

    With a light dilaton $\sigma$ and the light-quark vector mesons $V=(\rho ,\omega )$ incorporated into an effective scale-invariant hidden local symmetric Lagrangian, scale-chiral symmetry -- hidden in QCD -- arises at a high density, $n_{1/2}$, as an "emergent" symmetry, a phenomenon absent in standard chiral perturbative approaches but highly relevant for massive compact stars. What takes place as the density increases beyond $n_{1/2}\sim 2n_0$ in compressed baryonic matter is (1) a topology change from skyrmions to half-skyrmions, (2) parity doubling in the nucleon structure, (3) the maximum neutron star mass $M\simeq 2.01M_{\odot }$ and the radius $R\simeq 12.0$ km and (4) the sound velocity $v_s^2/c^2\simeq 1/3$ due to the "vector manifestation (VM)" fixed point of $\rho$ and a "walking" dilaton condensate, which is intricately connected to the source of the proton mass.

    ↳ nucl-thhep-ph6 citations
31. 31*

    Universality for quintessence

    F. Cicciarella🇮🇹 · M. Pieroni🇫🇷

    Several recent works suggested the possibility of describing inflation by means of a renormalization group equation. In this paper we discuss the application of these methods to models of quintessence. In this framework a period of exponential expansion corresponds to the slow evolution of the scalar field in the neighborhood of a fixed point. A minimal set of universality classes for models of quintessence is defined and the transition from a matter dominated to quintessence dominated universe is studied. Models in which quintessence is non-minimally coupled with gravity are also discussed. We show that the formalism proves to be extremely convenient to describe quintessence and moreover we find that in most of the models discussed in this work quintessence naturally takes over ordinary matter.

    ↳ gr-qcastro-ph.COhep-phJCAP(2017)·21 citations
32. 32*

    Non-perturbative aspects of Euclidean Yang-Mills theories in linear covariant gauges: Nielsen identities and a BRST invariant two-point correlation function

    M. A. L. Capri🇧🇷 · D. Dudal🇧🇪 · A. D. Pereira🇧🇷 · D. Fiorentini🇧🇷 · M. S. Guimaraes🇧🇷 · B. W. Mintz🇧🇷 · L. F. Palhares🇧🇷 · S. P. Sorella🇧🇷

    In order to construct a gauge invariant two-point function in a Yang-Mills theory, we propose the use of the all-order gauge invariant transverse configurations A^h. Such configurations can be obtained through the minimization of the functional A^2_{min} along the gauge orbit within the BRST invariant formulation of the Gribov-Zwanziger framework recently put forward in [1,2] for the class of the linear covariant gauges. This correlator turns out to provide a characterization of non-perturbative aspects of the theory in a BRST invariant and gauge parameter independent way. In particular, it turns out that the poles of <A^h A^h> are the same as those of the transverse part of the gluon propagator, which are also formally shown to be independent of the gauge parameter entering the gauge condition through the Nielsen identities. The latter follow from the new exact BRST invariant formulation introduced before. Moreover, the correlator <A^h A^h> enables us to attach a BRST invariant meaning to the possible positivity violation of the corresponding temporal Schwinger correlator, giving thus for the first time a consistent, gauge parameter independent, setup to adopt the positivity violation of <A^h A^h> as a signature for gluon confinement. Finally, in the context of gauge theories supplemented with a fundamental Higgs field, we use <A^h A^h> to probe the pole structure of the massive gauge boson in a gauge invariant fashion.

    ↳ hep-thhep-lathep-phPRD(2017)·61 citations
33. 33*

    Constraints on violation of Lorentz invariance from atmospheric showers initiated by multi-TeV photons

    Grigory Rubtsov🇷🇺 · Petr Satunin🇷🇺 · Sergey Sibiryakov🇨🇭

    We discuss the effect of hypothetical violation of Lorentz invariance at high energies on the formation of atmospheric showers by very-high-energy gamma rays. In the scenario where Lorentz invariance violation leads to a decrease of the photon velocity with energy the formation of the showers is suppressed compared to the Lorentz invariant case. Absence of such suppression in the high-energy part of spectrum of the Crab nebula measured independently by HEGRA and H.E.S.S. collaborations is used to set lower bounds on the energy scale of Lorentz invariance violation. These bounds are competitive with the strongest existing constraints obtained from timing of variable astrophysical sources and the absorption of TeV photons on the extragalactic background light. They will be further improved by the next generation of multi-TeV gamma-ray observatories.

    ↳ astro-ph.HEhep-phJCAP(2017)·67 citations
34. 34*

    Higher-order baryon number susceptibilities: interplay between the chiral and the nuclear liquid-gas transitions

    A. Mukherjee🇩🇪 · S. Schramm🇩🇪 · J. Steinheimer🇩🇪

    We use an improved version of the SU(3) flavour parity-doublet quark-hadron model to investigate the higher order baryon number susceptibilities near the chiral and the nuclear liquid-gas transitions. The parity-doublet model has been improved by adding higher-order interaction terms of the scalar fields in the effective mean field Lagrangian, resulting in a much-improved description of nuclear ground-state properties, in particular the nuclear compressibility. The resulting phase diagram of the model agrees qualitatively with expectations from lattice QCD, i.e., it shows a crossover at zero net baryo-chemical potential and a critical point at finite density. Using this model, we investigate the dependence of the higher-order baryon number susceptibilities as function of temperature and chemical potential. We observe a strong interplay between the chiral and liquid-gas transition at intermediate baryo chemical potentials. Due to this interplay between the chiral and the nuclear liquid-gas transitions, the experimentally measured cumulants of the net baryon number may show very different beam energy dependence, subject to the actual freeze-out temperature.

    ↳ nucl-thhep-phPRC(2017)·74 citations
35. 35*

    Nuclear pasta and supernova neutrinos at late times

    C. J. Horowitz🇺🇸 · D. K. Berry🇺🇸 · M. E. Caplan🇺🇸 · T. Fischer🇵🇱 · Zidu Lin🇺🇸 · W. G. Newton🇺🇸 · E. O'Connor🇺🇸 · L. F. Roberts🇺🇸

    Nuclear pasta, with nucleons arranged into tubes, sheets, or other complex shapes, is expected in core collapse supernovae (SNe) at just below nuclear density. We calculate the additional opacity from neutrino-pasta coherent scattering using molecular dynamics simulations. We approximately include this opacity in simulations of SNe. We find that pasta slows neutrino diffusion and greatly increases the neutrino signal at late times of 10 or more seconds after stellar core collapse. This signal, for a galactic SN, should be clearly visible in large detectors such as Super-Kamiokande.

    ↳ astro-ph.HEhep-phnucl-th32 citations
36. 36*

    Perspective on the cosmic-ray electron spectrum above TeV

    Kun Fang🇨🇳 · Bing-Bing Wang🇨🇳 · Xiao-Jun Bi🇨🇳 · Su-Jie Lin🇨🇳 · Peng-Fei Yin🇨🇳

    The AMS-02 has measured the cosmic ray electron (plus positron) spectrum up to ~TeV with an unprecedent precision. The spectrum can be well described by a power law without any obvious features above 10 GeV. The satellite instrument Dark Matter Particle Explorer (DAMPE), which was launched a year ago, will measure the electron spectrum up to 10 TeV with a high energy resolution. The cosmic electrons beyond TeV may be attributed to few local cosmic ray sources, such as supernova remnants. Therefore, spectral features, such as cutoff and bumps, can be expected at high energies. In this work we give a careful study on the perspective of the electron spectrum beyond TeV. We first examine our astrophysical source models on the latest leptonic data of AMS-02 to give a self-consistent picture. Then we focus on the discussion about the candidate sources which could be electron contributors above TeV. Depending on the properties of the local sources (especially on the nature of Vela), DAMPE may detect interesting features in the electron spectrum above TeV in the future.

    ↳ astro-ph.HEhep-phApJ(2017)·34 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.