Wed·Nov 22, 2017Wednesday·November 22, 2017

1. 01*

   Pomeron Physics at the LHC

   Federico Deganutti🇺🇸 · David Gordo Gomez🇪🇸 · Timothy Raben🇺🇸 · Christophe Royon🇺🇸

   We present current and ongoing research aimed at identifying Pomeron effects at the LHC in both the weak and strongly coupled regimes of QCD.

   hep-phEPJ Web Conf.(2018)·3 citations
2. 02*

   Radiative corrections to masses and couplings in Universal Extra Dimensions

   Ayres Freitas🇺🇸 · Kyoungchul Kong🇺🇸 · Daniel Wiegand🇺🇸

   Models with an orbifolded universal extra dimension receive important loop-induced corrections to the masses and couplings of Kaluza-Klein (KK) particles. The dominant contributions stem from so-called boundary terms which violate KK number. Previously, only the parts of these boundary terms proportional to $\ln (\Lambda R)$ have been computed, where $R$ is the radius of the extra dimension and $\Lambda$ is cut-off scale. However, for typical values of $\Lambda R\sim 10\cdots 50$, the logarithms are not particularly large and non-logarithmic contributions may be numerically important. In this paper, these remaining finite terms are computed and their phenomenological impact is discussed. It is shown that the finite terms have a significant impact on the KK mass spectrum. Furthermore, one finds new KK-number violating interactions that do not depend on $\ln (\Lambda R)$ but nevertheless are non-zero. These lead to new production and decay channels for level-2 KK particles at colliders.

   hep-phJHEP(2018)·12 citations
3. 03*

   Finite size effects in strongly interacting matter at zero chemical potential from Polyakov loop Nambu-Jona-Lasinio model in the light of lattice data

   A. G. Grunfeld🇦🇷 · G. Lugones🇧🇷

   We study finite volume effects within the Polyakov loop Nambu-Jona-Lasinio model for two light and one heavy quarks at vanishing baryon chemical potential and finite temperatures. We include three different Polyakov loop potentials and ensure that the predictions of our effective model in bulk are compatible with lattice QCD results. Finite size effects are taken into account by means of the Multiple Reflection Expansion formalism. We analyze several thermodynamic quantities including the interaction measure, the speed of sound, the surface tension, and the curvature energy and find that they are sensitive to finite volume effects, specially for systems with radii below $\sim 10$ fm and temperatures around the crossover one. For all sizes, the system undergoes a smooth crossover. The chiral critical temperature decreases by around $5\%$ and the deconfinement temperature by less than a $2\%$ when the radius goes from infinity to 3 fm. Thus, as the drop's size decreases, both temperatures become closer. The surface tension is dominated by the contribution of strange quarks and the curvature energy by $u$ and $d$ quarks. At large temperatures both quantities grow proportionally to $T^{3/2}$ but saturate to a constant value at low $T$.

   hep-phEPJC(2018)·22 citations
4. 04*

   Constraining the Compressed Top Squark and Chargino along the W Corridor

   Hsin-Chia Cheng🇺🇸 · Lingfeng Li🇺🇸 · Qin Qin

   Studying superpartner production together with a hard initial state radiation (ISR) jet has been a useful strategy for searches of supersymmetry with a compressed spectrum at the Large Hadron Collider (LHC). In the case of the top squark (stop), the ratio of the missing transverse momentum from the lightest neutralinos and the ISR momentum, defined as ${\bar{R}}_M$, turns out to be an effective variable to distinguish the signal from the backgrounds. It has helped to exclude the stop mass below 590 GeV along the top corridor where $m_{\tilde{t}}-m_{{\tilde{\chi }}_1^0}\approx m_t$. On the other hand, the current experimental limit is still rather weak in the $W$ corridor where $m_{\tilde{t}}-m_{{\tilde{\chi }}_1^0}\approx m_W+m_b$. In this work we extend this strategy to the parameter region around the $W$ corridor by considering the one lepton final state. In this case the kinematic constraints are insufficient to completely determine the neutrino momentum which is required to calculate ${\bar{R}}_M$. However, the minimum value of ${\bar{R}}_M$ consistent with the kinematic constraints still provides a useful discriminating variable, allowing the exclusion reach of the stop mass to be extended to $\sim 550$ GeV based on the current 36 fb${}^{-1}$ LHC data. The same method can also be applied to the chargino search with $m_{{\tilde{\chi }}_1^{\pm }}-m_{{\tilde{\chi }}_1^0}\approx m_W$ because the analysis does not rely on $b$ jets. If no excess is present in the current data, a chargino mass of 300 GeV along the $W$ corridor can be excluded, beyond the limit obtained from the multilepton search.

   hep-phhep-exPRD(2018)·2 citations
5. 05*

   Leptogenesis Constraints on $B-L$ breaking Higgs Boson in TeV Scale Seesaw Models

   P. S. Bhupal Dev🇺🇸 · Rabindra N. Mohapatra🇺🇸 · Yongchao Zhang🇺🇸

   In the type-I seesaw mechanism for neutrino masses, there exists a $B-L$ symmetry, whose breaking leads to the lepton number violating mass of the heavy Majorana neutrinos. This would imply the existence of a new neutral scalar associated with the $B-L$ symmetry breaking, analogous to the Higgs boson of the Standard Model. If in such models, the heavy neutrino decays are also responsible for the observed baryon asymmetry of the universe via the leptogenesis mechanism, the new seesaw scalar interactions with the heavy neutrinos will induce additional dilution terms for the heavy neutrino and lepton number densities. We make a detailed study of this dilution effect on the lepton asymmetry in three generic classes of seesaw models with TeV-scale $B-L$ symmetry breaking, namely, in an effective theory framework and in scenarios with global or local $U(1{)}_{B-L}$ symmetry. We find that requiring successful leptogenesis imposes stringent constraints on the mass and couplings of the new scalar in all three cases, especially when it is lighter than the heavy neutrinos. We also discuss the implications of these new constraints and prospects of testing leptogenesis in presence of seesaw scalars at colliders.

   hep-phastro-ph.COhep-exJHEP(2018)·47 citations
6. 06*

   Searching for possible ${\Omega }_c-$like molecular states from ${\Xi }_c^{\ast }\bar{K}/{\Xi }_c{\bar{K}}^{\ast }/{\Xi }_c^{\prime }{\bar{K}}^{\ast }$ interaction

   Rui Chen🇨🇳 · Xiang Liu🇨🇳 · Atsushi Hosaka🇯🇵

   Stimulated by the observations of recent observation of ${\Omega }_c$ as well as former one of $P_c(4380)$ and $P_c(4450)$, we perform a coupled channel analysis of ${\Xi }_c^{\ast }\bar{K}/{\Omega }_c\eta /{\Omega }_c^{\ast }\eta /{\Xi }_c{\bar{K}}^{\ast }/{\Xi }_c^{\prime }{\bar{K}}^{\ast }/{\Omega }_c\omega$ systems to search for possible ${\Omega }_c-$like molecular states by using a one-boson-exchange potential. Our results suggest there exists a loosely bound molecular state, a ${\Xi }_c^{\ast }\bar{K}/{\Omega }_c\eta /{\Omega }_c^{\ast }\eta /{\Xi }_c{\bar{K}}^{\ast }/{\Xi }_c^{\prime }{\bar{K}}^{\ast }/{\Omega }_c\omega$ with $I(J^P)=0(3/2^{-})$, it is mainly composed of the ${\Xi }_c^{\ast }\bar{K}$ system. Two-body strong decay width is also studied, where we find that ${\Xi }_c^{\prime }\bar{K}$ is the dominant decay channel.

   hep-phPRD(2018)·67 citations
7. 07*

   Narrow-width tetraquarks in large-$N_{\mathrm{c}}^{}$ QCD

   Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇦🇹 · Hagop Sazdjian🇫🇷

   The properties of possibly existing tetraquarks are studied in the large-$N_{\mathrm{c}}^{}$ limit of QCD by means of four-point correlation functions of meson currents.The necessity of a detailed analysis of the singularities of Feynman diagrams, by means of the Landau equations, to recognize those diagrams that might contribute to the formation of tetraquark states, is emphasized. It is found, in general, that tetraquarks, if they exist, should have narrow widths of the order of $N_{\mathrm{c}}^{-2}$.

   hep-phEPJ Web Conf.(2018)·2 citations
8. 08*

   Gaussian-weighted Parton Quasi-distribution

   Tomomi Ishikawa🇨🇳 · Luchang Jin🇺🇸 · Huey-Wen Lin🇺🇸 · Andreas Schäfer🇩🇪 · Yi-Bo Yang🇺🇸 · Jian-Hui Zhang🇩🇪 · Yong Zhao🇺🇸

   We propose a revised definition of quasi-distributions within the framework of large-momentum effective theory (LaMET) that improves convergence towards the large-momentum limit. Since the definition of quasi-distributions is not unique, each choice goes along with a specific matching function, we can use this freedom to optimize convergence towards the large-momentum limit. As an illustration, we study quasi-distributions with a Gaussian weighting factor that naturally suppresses long-range correlations, which are plagued by artifacts. This choice has the advantage that the matching functions can be trivially obtained from the known ones. We apply the Gaussian weighting to the previously published results for the nonperturbatively renormalized unpolarized quark distribution, and find that the unphysical oscillatory behavior is significantly reduced.

   hep-phhep-latSCPMA(2019)·57 citations
9. 09*

   Dispersive analysis tools for $\pi \pi$ and $\pi K$ scattering

   J.R. Peláez🇪🇸 · A. Rodas (Universidad Complutense de Madrid)🇪🇸

   In this talk we discuss the relevance of dispersive methods and their different applications to obtain simple but rigorous parameterizations of pion-pion and kaon-pion scattering. We show as an example our latest dispersive analysis of $\pi K$ scattering, where we provide simple parameterizations of data satisfying Forward Dispersion Relations up to 1.6 GeV.

   hep-phnucl-thPoS(2018)·2 citations
10. 10*

    Multi-lepton signatures of additional scalar bosons beyond the Standard Model at the LHC

    Stefan von Buddenbrock🇿🇦 · Alan S. Cornell🇿🇦 · Abdualazem Fadol🇿🇦 · Mukesh Kumar🇿🇦 · Bruce Mellado🇿🇦 · Xifeng Ruan🇿🇦

    Following a prediction made in Refs.~\cite{vonBuddenbrock:2015ema,Kumar:2016vut,vonBuddenbrock:2016rmr}, this paper focuses on multi-lepton signatures arising from two new hypothetical scalar bosons, $H$ and $S$, at the Large Hadron Collider (LHC). These two new bosons are an extension to the Standard Model (SM) and interact with the SM Higgs boson, $h$. We consider two production modes for $H$, one being gluon fusion and the other being in association with top quarks. The $H\to Sh$ decay mode is considered, where leptonic final states are studied. The CP properties of $S$ are characterised by considering effective couplings derived from dimension six operators through $SWW$ vertices. The nature of the $S$ boson is considered in two separate contexts. Firstly in a simplified model, it is considered to have Higgs-like couplings. Secondly, we consider a heavy neutrino model and its interactions with the $Z,W$ and $S$ bosons. The predictions of the models are compared both to ATLAS and CMS results at $\sqrt{s}=8$ and $13$~TeV, where appropriate. The data is interpreted using a simplified model where all the signal comes from $H\to Sh$, assuming $S$ to be Higgs-like, $m_H=270$~GeV and $m_S=150$~GeV. The combined result yields gives a best fit value for the parameter ${\beta }_g$ (the strength of the Yukawa coupling of $H$ to top quarks), ${\beta }_g^2=1.38\pm 0.22$. A number of regions of the phase space are suggested to the experiments for further exploration.

    hep-phJ.Phys.G(2018)·70 citations
11. 11*

    Isospin Breaking in Heavy-Meson Decay Constants

    Wolfgang Lucha🇦🇹 · Dmitri Melikhov🇦🇹 · Silvano Simula🇮🇹

    Evaluation of Borelized QCD sum rules in the so-called local-duality limit of infinitely large Borel mass parameter provides an alternate route for extraction of the dependence of the decay constants of heavy-light mesons on the mass $m_q$ of the involved light quark $q$: For appropriate choices of the two-point correlation functions of currents interpolating the hadrons under study, the local-duality limit forces all nonperturbative contributions parametrized by vacuum condensates to such kind of correlator to vanish. As a consequence, the sought $m_q$ dependence of the heavy-light meson decay constants proves to be controlled primarily by the correlator contributions from perturbative QCD. Our knowledge of the analytic behaviour of the latter as functions of $m_q$ enables us to derive the $m_q$ dependence of the decay constants of both pseudoscalar and vector heavy-light mesons, for which we estimate strong isospin breaking to be of the order of 1 MeV for both charm and beauty sectors.

    hep-phhep-latnucl-thPoS(2018)·2 citations
12. 12*

    Parton distributions and lattice QCD calculations: a community white paper

    Huey-Wen Lin🇺🇸 · Emanuele R. Nocera🇬🇧 · Fred Olness🇺🇸 · Kostas Orginos🇺🇸 · Juan Rojo (editors)🇳🇱 · Alberto Accardi🇺🇸 · Constantia Alexandrou🇨🇾 · Alessandro Bacchetta🇮🇹 · Giuseppe Bozzi🇮🇹 · Jiunn-Wei Chen🇹🇼 · Sara Collins🇩🇪 · Amanda Cooper-Sarkar🇬🇧 and 20 other authors

    In the framework of quantum chromodynamics (QCD), parton distribution functions (PDFs) quantify how the momentum and spin of a hadron are divided among its quark and gluon constituents. Two main approaches exist to determine PDFs. The first approach, based on QCD factorization theorems, realizes a QCD analysis of a suitable set of hard-scattering measurements, often using a variety of hadronic observables. The second approach, based on first-principle operator definitions of PDFs, uses lattice QCD to compute directly some PDF-related quantities, such as their moments. Motivated by recent progress in both approaches, in this document we present an overview of lattice-QCD and global-analysis techniques used to determine unpolarized and polarized proton PDFs and their moments. We provide benchmark numbers to validate present and future lattice-QCD calculations and we illustrate how they could be used to reduce the PDF uncertainties in current unpolarized and polarized global analyses. This document represents a first step towards establishing a common language between the two communities, to foster dialogue and to further improve our knowledge of PDFs.

    hep-phhep-latPPNP(2018)·340 citations
13. 13*

    On interference and non-interference in the SMEFT

    Andreas Helset🇩🇰 · Michael Trott🇩🇰

    We discuss interference in the limit ${\hat{m}}_W^2/s\to 0$ in the Standard Model Effective Field Theory (SMEFT). Dimension six operators that contribute to $\bar{\psi }\psi \to {\overline{{\psi }^{\prime }}}_1{\psi }_2^{\prime }{\overline{{\psi }^{\prime }}}_3{\psi }_4^{\prime }$ scattering events can experience a suppression of interference effects with the Standard Model in this limit. This occurs for subsets of phase space in some helicity configurations. We show that approximating these scattering events by $2\to 2$ on-shell scattering results for intermediate unstable gauge bosons, and using the narrow width approximation, can miss interference terms present in the full phase space. Such interference terms can be uncovered using off-shell calculations as we explicitly show and calculate. We also study the commutation relation between the SMEFT expansion and the narrow width approximation, and discuss some phenomenological implications of these results.

    hep-phJHEP(2018)·26 citations
14. 14*

    Heavy Flavor Wilson Coefficients in Deep-Inelastic Scattering: Recent Results

    J. Ablinger · A. Behring · J. Blümlein · A. De Freitas · A. von Manteuffel · C. Schneider

    We present recent analytic results for the 3-loop corrections to the massive operator matrix element $A_{Qg}^{(3)}$for further color factors. These results have been obtained using the method of arbitrarily large moments. We also give an overview on the results which were obtained solving all difference and differential equations for the corresponding master integrals that factorize at first order.

    hep-phPoS(2017)·51 citations
15. 15*

    Charged Higgs in MSSM and Beyond

    Yasar Hicyilmaz🇹🇷 · Levent Selbuz🇹🇷 · Levent Solmaz🇹🇷 · Cem Salih Un🇹🇷

    We conduct a numerical study over the constrained MSSM (CMSSM), Next-to-MSSM (NMSSM) and $U(1)$ extended MSSM (UMSSM) to probe the allowed mass ranges of the charged Higgs boson and its dominant decay patterns, which might come into prominence in near future collider experiments. {We present results obtained from a limited scan for CMSSM} as a basis and compare its predictions with the extended models. We observe within our data that a wide mass range is allowed as $0.5(1)\lesssim m_{H^{\pm }}\lesssim 17$ TeV in UMSSM (NMSSM). We find that the dominant decay channel is mostly $H^{\pm }\to tb$ such that $\mathrm{BR}(H^{\pm }\to tb)\sim 80\%$. While this mode remains dominant over the whole allowed parameter space of CMSSM, we realize some special domains in the NMSSM and UMSSM, in which $\mathrm{BR}(H^{\pm }\to tb)\lesssim 10\%$. In this context, the decay patterns of the charged Higgs can play a significant role to distinguish among the SUSY models. In addition to the $tb$ decay mode, we find that the narrow mass scale in CMSSM allows only the decay modes for the charged Higgs boson to $\tau \nu$ ($\sim 16\%$), and their supersymmetric partners $\tilde{\tau }\tilde{\nu }$ ($\sim 13\%$). On the other hand, it is possible to realize the mode in NMSSM and UMSSM in which the charged Higgs boson decays into a chargino and neutralino pair up to about $25\%$. {This decay mode requires non-universal boundary conditions within the MSSM framework to be available, since CMSSM yields $\mathrm{BR}(H^{\pm }\to {\tilde{\chi }}_1^0{\tilde{\chi }}_1^{\pm })\lesssim 1\%$.} It can also be probed in near future collider experiments through the missing energy and CP-violation measurements...

    hep-phPRD(2018)·8 citations
16. 16*

    Charged Higgs observability in the single top production channel at LHC

    Nadia Kausar🇩🇰 · Ijaz Ahmed🇩🇰

    Single top quark production through weak interactions is an important source of charged Higgs in the Minimal Super Symmetric Standard Model. In the s-channel single top production ,charged Higgs having largest cross-section may appear as a propagator in the form of heavy resonance state decaying to a pair of top and bottom quark. In this paper the channel under consideration is $pp\to H^{\pm }\to tb\to b\bar{b}{W}^{\pm }\to b\bar{b}{\tau }^{\pm }{\nu }_{\tau }$, where top quark exclusively decays into a pair of b quark and W boson while W boson subsequently decays to $\tau$ jet and neutrino. So the final state is characterized by the presence of two b jets, hadronic $\tau$ decay and missing transverse energy.It has been demonstrated that the charged Higgs signal observability is possible within the available MSSM parameter space (tan$\beta$, $m_{H^{\pm }})$ respecting all experimental and theoretical constraints due to presence of QCD multijet and electroweak background events at LHC. In order to show the observability potential of charged Higgs, the charged Higgs signal are well observed or excluded in a wide range of phase space particular ($\beta >35$ at 500 $f{b}^{-1}$ , $\beta >25$ at 1000 $f{b}^{-1}$ , $\beta >15$ at 3000 $f{b}^{-1}$ ) at $\sqrt{s}=$14 TeV.

    hep-phInt.J.Theor.Phys.(2021)·1 citation
17. 17*

    Exclusive diffractive resonance production in proton-proton collisions at high energies

    R. Fiore🇮🇹 · L. Jenkovszky🇺🇦 · R. Schicker🇩🇪

    A model for exclusive diffractive resonance production in proton-proton collisions at high energies is presented. This model is able to predict double differential distributions with respect to the mass and the transverse momentum of the produced resonance in the mass region $\sqrt{M^2}\le$5 GeV. The model is based on convoluting the Pomeron distribution in the proton with the Pomeron-Pomeron-meson total cross section. The Pomeron-Pomeron-meson cross section is saturated by direct-channel contributions from the Pomeron as well as from two different $f$ trajectories, accompanied by the isolated f${}_0(500)$ resonance dominating the $\sqrt{M^2}\le$ GeV region. A slowly varying background is taken into account.

    hep-phEPJC(2018)·15 citations
18. 18*

    Pion Condensation by Rotation in a Magnetic field

    Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸

    We show that the combined effects of a rotation plus a magnetic field can cause charged pion condensation. We suggest that this phenomenon may yield to observable effects in current heavy ion collisions at collider energies, where large magnetism and rotations are expected in off-central collisions.

    hep-phhep-thnucl-exnucl-thPRL(2018)·83 citations
19. 19*

    Tests of the charged Goldstone sector through inclusive $t\bar{b}$ production

    Fernand M. Renard🇫🇷

    Similarly to the previously studied case of inclusive $t\bar{t}$ production we consider the inclusive $t\bar{b}$ production in $e^{+}{e}^{-}$, gluon~gluon and photon~photon collisions. We show how it is sensitive to new physics, connected to the charged Goldstone sector and possibly generated by Higgs and/or top quark compositeness.

    hep-ph0 citations
20. 20*

    Non-perturbative constraints on the quark and ghost propagators

    Peter Lowdon🇺🇸

    In QCD both the quark and ghost propagators are important for governing the non-perturbative dynamics of the theory. It turns out that the dynamical properties of the quark and ghost fields impose non-perturbative constraints on the analytic structure of these propagators. In this work we explicitly derive these constraints. In doing so we establish that the corresponding spectral densities include components which are multiples of discrete mass terms, and that the propagators are permitted to contain singular contributions involving derivatives of $\delta (p)$, both of which are particularly relevant in the context of confinement.

    ↳ hep-thhep-phNPB(2018)·25 citations
21. 21*

    Principal component analysis of the nonlinear coupling of harmonic modes in heavy-ion collisions

    Piotr Bozek🇵🇱

    The principal component analysis of flow correlations in heavy-ion collisions is studied. The correlation matrix of harmonic flow is generalized to correlations involving several different flow vectors. The method can be applied to study the nonlinear coupling between different harmonic modes in a double differential way in transverse momentum or pseudorapidity. The procedure is illustrated with results from the hydrodynamic model applied to Pb+Pb collisions at $\sqrt{s}=2760$GeV. Three examples of generalized correlations matrices in transverse momentum are constructed corresponding to the coupling of $v_2^2$ and $v_4$, of $v_2{v}_3$ and $v_5$, or of $v_2^3$, $v_3^3$, and $v_6$. The principal component decomposition is applied to the correlation matrices and the dominant modes are calculated.

    ↳ nucl-thhep-phnucl-exPRC(2018)·22 citations
22. 22*

    Event-by-event fluctuations in p+p and central A+A collisions within relativistic transport models

    Anton Motornenko🇩🇪 · Katarzyna Grebieszkow🇵🇱 · Elena Bratkovskaya🇩🇪 · Mark I. Gorenstein🇺🇦 · Marcus Bleicher🇩🇪 · Klaus Werner🇫🇷

    Event-by-event multiplicity fluctuations in nucleus-nucleus collisions are studied within the relativistic transport models: EPOS, PHSD, and UrQMD. As measures of particle number fluctuations we consider the scaled variances $\omega [X]$ for positive, negative, and all charged hadrons, and the strongly intensive quantities $\Delta [K^{+},{\pi }^{+}],$ $\Sigma [K^{+},{\pi }^{+}]$ for $K^{+}$ and ${\pi }^{+}$ yields. At the SPS energy range the fluctuation measures are calculated for proton-proton, Ar+Sc, and Pb+Pb collisions. Comparison with recent NA61/SHINE and older NA49 measurements of the multiplicity fluctuations is done. A validity of the model of independent sources, a role of the experimental acceptance, and the centrality selection procedure are studied.Event-by-event multiplicity fluctuations in nucleus-nucleus collisions are studied within the relativistic transport models: EPOS, PHSD, and UrQMD. As measures of particle number fluctuations we consider the scaled variances $\omega [X]$ for positive, negative, and all charged hadrons, and the strongly intensive quantities $\Delta [K^{+},{\pi }^{+}],$ $\Sigma [K^{+},{\pi }^{+}]$ for $K^{+}$ and ${\pi }^{+}$ yields. At the SPS energy range the fluctuation measures are calculated for proton-proton, Ar+Sc, and Pb+Pb collisions. Comparison with recent NA61/SHINE and older NA49 measurements of the multiplicity fluctuations is done. A validity of the model of independent sources, a role of the experimental acceptance, and the centrality selection procedure are studied.

    ↳ nucl-thhep-phJ.Phys.G(2018)·11 citations
23. 23*

    Finite-size effects on the Phase Structure of the Walecka Model

    L. M. Abreu🇧🇷 · E. S. Nery🇧🇷

    In this work we investigate the finite-size effects on the phase structure of Walecka model within the framework of generalized Zeta-function, focusing on the influence of temperature as well as the number and length of compactified spatial dimensions. Here we concentrate on the situation of larger values of the coupling between the scalar and fermion fields, in which a phase transition of first order takes place. The phase transitions are analyzed and compared with the system in the situations of one, two and three compactified spatial dimensions. Our findings suggest that the thermodynamic behavior of the system depends on the length and number of spatial dimensions, with the symmetric phase being favored as the size of the system diminishes.

    ↳ nucl-thhep-phhep-thPRC(2017)·19 citations
24. 24*

    Three-fluid Hydrodynamics-based Event Simulator Extended by UrQMD final State interactions (THESEUS) for FAIR-NICA-SPS-BES/RHIC energies

    P. Batyuk🇷🇺 · D. Blaschke🇷🇺 · M. Bleicher🇩🇪 · Yu.B. Ivanov🇷🇺 · Iu. Karpenko🇮🇹 · L. Malinina🇷🇺 · S. Merts🇷🇺 · M. Nahrgang🇫🇷 · H. Petersen🇩🇪 · O. Rogachevsky🇷🇺

    We present a new event generator based on the three-fluid hydrodynamics (3FH) approach, followed by a particlization at the hydrodynamic decoupling surface and a subsequent UrQMD afterburner stage based on the microscopic UrQMD transport model that accounts for hadronic final state interactions. First results for Au+Au collisions are presented. The following topics are addressed: the directed flow, transverse-mass spectra, as well as rapidity distributions of protons, pions and kaons for two model equations of state, one with a first-order phase transition, the other with a crossover transition. Preliminary results on the femtoscopy are also discussed. We analyze the accuracy of reproduction of the 3FH results by the new event generator and the effect of the subsequent UrQMD afterburner stage.

    ↳ nucl-thhep-exhep-phnucl-exEPJ Web Conf.(2018)·18 citations
25. 25*

    Statefinder diagnostic and constraints on the Palatini f(R) gravity theories

    Shu-Lei Cao🇨🇳 · Song Li🇨🇳 · Hao-Ran Yu🇨🇳 · Tong-Jie Zhang🇨🇳

    We focus on a series of $f(R)$ gravity theories in Palatini formalism to investigate the probabilities of producing the late-time acceleration for the flat Friedmann-Robertson-Walker (FRW) universe. We apply statefinder diagnostic to these cosmological models for chosen series of parameters to see if they distinguish from one another. The diagnostic involves the statefinder pair $\{r,s\}$, where $r$ is derived from the scale factor $a$ and its higher derivatives with respect to the cosmic time $t$, and $s$ is expressed by $r$ and the deceleration parameter $q$. In conclusion, we find that although two types of $f(R)$ theories: (i) $f(R)=R+\alpha R^m-\beta R^{-n}$ and (ii) $f(R)=R+\alpha \ln R-\beta$ can lead to late-time acceleration, their evolutionary trajectories in the $r-s$ and $r-q$ planes reveal different evolutionary properties, which certainly justify the merits of statefinder diagnostic. Additionally, we utilize the observational Hubble parameter data (OHD) to constrain these models of $f(R)$ gravity. As a result, except for $m=n=1/2$ of (i) case, $\alpha =0$ of (i) case and (ii) case allow $\Lambda$CDM model to exist in 1$\sigma$ confidence region. After adopting statefinder diagnostic to the best-fit models, we find that all the best-fit models are capable of going through deceleration/acceleration transition stage with late-time acceleration epoch, and all these models turn to de-Sitter point ($\{r,s\}=\{1,0\}$) in the future. Also, the evolutionary differences between these models are distinct, especially in $r-s$ plane, which makes the statefinder diagnostic more reliable in discriminating cosmological models.

    ↳ gr-qcastro-ph.COhep-phhep-thRes.Astron.Astrophys.(2018)·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.