Fri·Nov 27, 2015Friday·November 27, 2015

1. 01*

   Boson-Jet Correlations in a Hybrid Strong/Weak Coupling Model for Jet Quenching in Heavy Ion Collisions

   Jorge Casalderrey-Solana🇪🇸 · Doga Can Gulhan🇺🇸 · Jose Guilherme Milhano🇵🇹 · Daniel Pablos🇪🇸 · Krishna Rajagopal🇺🇸

   We confront a hybrid strong/weak coupling model for jet quenching to data from LHC heavy ion collisions. The model combines the perturbative QCD physics at high momentum transfer and the strongly coupled dynamics of non- abelian gauge theories plasmas in a phenomenological way. By performing a full Monte Carlo simulation, and after fitting one single parameter, we successfully describe several jet observables at the LHC, including dijet and photon jet measurements. Within current theoretical and experimental uncertainties, we find that such observables show little sensitivity to the specifics of the microscopic energy loss mechanism. We also present a new observable, the ratio of the fragmentation function of inclusive jets to that of the associated jets in dijet pairs, which can discriminate among different medium models. Finally, we discuss the importance of plasma response to jet passage in jet shapes.

   hep-phNucl.Part.Phys.Proc.(2016)·1 citation
2. 02*

   Electroweak top-quark pair production at the LHC with $Z^{\prime }$ bosons to NLO QCD in POWHEG

   R. Bonciani🇮🇹 · T. Jezo🇮🇹 · M. Klasen🇩🇪 · F. Lyonnet🇺🇸 · I. Schienbein🇫🇷

   We present the calculation of the NLO QCD corrections to the electroweak production of top-antitop pairs at the CERN LHC in the presence of a new neutral gauge boson. The corrections are implemented in the parton shower Monte Carlo program POWHEG. Standard Model (SM) and new physics interference effects are properly taken into account. QED singularities, first appearing at this order, are consistently subtracted. Numerical results are presented for SM and $Z^{\prime }$ total cross sections and distributions in invariant mass, transverse momentum, azimuthal angle and rapidity of the top-quark pair. The remaining theoretical uncertainty from scale and PDF variations is estimated, and the potential of the charge asymmetry to distinguish between new physics models is investigated for the Sequential SM and a leptophobic topcolor model.

   hep-phhep-exJHEP(2016)·33 citations
3. 03*

   The Non-Linear Higgs Legacy of the LHC Run I

   Tyler Corbett🇦🇺 · Oscar J. P. Eboli🇧🇷 · Dorival Goncalves🇬🇧 · J. Gonzalez-Fraile🇩🇪 · Tilman Plehn🇩🇪 · Michael Rauch🇩🇪

   In the recent paper on "The Higgs Legacy of the LHC Run I" we interpreted the LHC Higgs results in terms of an effective Lagrangian using the SFitter framework. For the on-shell Higgs analysis of rates and kinematic distributions we relied on a linear representation based on dimension-6 operators with a simplified fermion sector. In this addendum we describe how the extension of Higgs couplings modifications in a linear dimension-6 Lagrangian can be formally understood in terms of the non-linear effective field theory. It turns out that our previous results can be translated to the non-linear framework through a simple operator rotation.

   hep-ph26 citations
4. 04*

   A new approach to analytic, non-perturbative, gauge-invariant QCD renormalization is described, with applications to high energy elastic pp-scattering

   H. M. Fried🇺🇸 · P. H. Tsang🇺🇸 · Y. Gabellini🇫🇷 · T. Grandou🇫🇷 · Y-M. Sheu🇺🇸

   A new non-perturbative, gauge-invariant model QCD renormalization is applied to high energy elastic pp-scattering. The differential cross-section deduced from this model displays a diffraction dip that resembles those of experiments. Comparison with ISR and LHC data is currently underway.

   hep-phhep-thEPJ Web Conf.(2016)·0 citations
5. 05*

   Potential NRQCD for unequal masses and the $B_c$ spectrum at NNNLO

   Clara Peset🇪🇸 · Antonio Pineda🇪🇸 · Maximilian Stahlhofen🇩🇪

   We determine the $1/m$ and $1/m^2$ spin-independent heavy quarkonium potentials in the unequal mass case with $\mathcal{O}({\alpha }^3)$ and $\mathcal{O}({\alpha }^2)$ accuracy, respectively. We discuss in detail different methods to calculate the potentials, and show the equivalence among them. In particular we obtain, for the first time, the manifestly gauge invariant $1/m$ and $1/m^2$ potentials in terms of Wilson loops with next-to-leading order (NLO) precision. As an application of our results we derive the theoretical expression for the $B_c$ spectrum in the weak-coupling limit through next-to-next-to-next-to-leading order (N${}^3$LO).

   hep-phhep-lathep-thJHEP(2016)·28 citations
6. 06*

   A Light Stop with a Heavy Gluino: Enlarging the Stop Gap

   Kevin F. Cleary🇺🇸 · John Terning🇺🇸

   It is widely thought that increasing bounds on the gluino mass, which feeds down to the stop mass through renormalization group running, are making a light stop increasingly unlikely. Here we present a counter-example. We examine the case of the Minimal Composite Supersymmetric Standard Model which has a light composite stop. The large anomalous dimension of the stop from strong dynamics pushes the stop mass toward a quasi-fixed point in the infrared, which is smaller than standard estimates by a factor of a large logarithm. The gluino can be about three times heavier than the stop, which is comparable to hierarchy achieved with supersoft Dirac gluino masses. Thus, in this class of models, a heavy gluino is not necessarily indicative of a heavy stop.

   hep-phJHEP(2016)·3 citations
7. 07*

   The Quantum Critical Higgs

   Brando Bellazzini🇫🇷 · Csaba Csáki🇺🇸 · Jay Hubisz🇺🇸 · Seung J. Lee🇰🇷 · Javi Serra🇨🇭 · John Terning🇺🇸

   The appearance of the light Higgs boson at the LHC is difficult to explain, particularly in light of naturalness arguments in quantum field theory. However light scalars can appear in condensed matter systems when parameters (like the amount of doping) are tuned to a critical point. At zero temperature these quantum critical points are directly analogous to the finely tuned standard model. In this paper we explore a class of models with a Higgs near a quantum critical point that exhibits non-mean-field behavior. We discuss the parametrization of the effects of a Higgs emerging from such a critical point in terms of form factors, and present two simple realistic scenarios based on either generalized free fields or a 5D dual in AdS space. For both of these models we consider the processes $gg\to ZZ$ and $gg\to hh$, which can be used to gain information about the Higgs scaling dimension and IR transition scale from the experimental data.

   hep-phcond-mat.str-elhep-thPRX(2016)·31 citations
8. 08*

   Higher order hadronic and leptonic contributions to the muon $g-2$

   Alexander Kurz🇩🇪 · Tao Liu🇨🇦 · Peter Marquard🇩🇪 · Alexander V. Smirnov🇷🇺 · Vladimir A. Smirnov🇷🇺 · Matthias Steinhauser🇩🇪

   In this contribution we discuss next-to-next-to-leading order hadronic and four-loop QED contributions to the anomalous magnetic moment of the muon.

   hep-phEPJ Web Conf.(2016)·10 citations
9. 09*

   Extending the Analysis of Electroweak Precision Constraints in Composite Higgs Models

   Diptimoy Ghosh🇮🇱 · Matteo Salvarezza🇮🇹 · Fabrizio Senia🇮🇹

   In this paper we present a detailed analysis of the Electroweak Precision Observables (EWPO) in composite Higgs models based on the coset $SO(5)/SO(4)$. In our study we include both the fermionic top partners and the spin-1 resonances and consider their possible interplay as well. In order to achieve calculability we use the assumptions of i) partial Ultra Violet Completion (PUVC) following arXiv:1109.1570 and, ii) absence of sizeable effects from physics above the cut-off. Apart from the EWPO, we also take into account the constraints from the top quark, $Z$ and the Higgs boson masses whenever they can be predicted in terms of the model parameters. After presenting our analytic results (often, in certain limits) and discussing their symmetry properties, we also perform detailed fits of the model parameters following the Bayesian approach. We show the posterior probability distributions of the parameters in various scenarios and provide with analytic understanding whenever possible. We find that in certain cases the EWPO allow the compositeness scale to lie well below $1$ TeV. Moreover, fermionic top partners of mass around $1$ TeV and spin-1 resonances of mass around $2-3$ TeV are consistent with the precision data.

   hep-phhep-exNPB(2017)·44 citations
10. 10*

    The decay $\tau \to K^{-}{\pi }^0{\nu }_{\tau }$ in the Nambu-Jona-Lasinio model

    M. K. Volkov🇷🇺 · A. A. Pivovarov (Dubna, JINR)🇷🇺

    In this paper, the width of the decay $\tau \to K^{-}{\pi }^0{\nu }_{\tau }$ is calculated in the framework of the Nambu-Jona-Lasinio model. The contributions of the intermediate vector $K^{\ast }(892)$ and scalar $K_0^{\ast }(800)$ mesons are taken into account. It is shown that the main contribution to the width of this decay is given by the subprocesses with the intermediate $W$-boson and vector $K^{\ast }(892)$ meson. The scalar channel with the intermediate $K_0^{\ast }(800)$ meson gives an insignificant contribution. In Appendix, it is shown that the contribution of the subprocess with the intermediate ${K^{\ast }}^{\prime }(1410)$ meson is negligible as well. The obtained results are in satisfactory agreement with the experimental data.

    hep-phMod.Phys.Lett.A(2016)·10 citations
11. 11*

    The gluon mass generation mechanism: a concise primer

    A. C. Aguilar🇧🇷 · D. Binosi🇮🇹 · J. Papavassiliou🇪🇸

    We present a pedagogical overview of the nonperturbative mechanism that endows gluons with a dynamical mass. This analysis is performed based on pure Yang-Mills theories in the Landau gauge, within the theoretical framework that emerges from the combination of the pinch technique with the background field method. In particular, we concentrate on the Schwinger-Dyson equation satisfied by the gluon propagator and examine the necessary conditions for obtaining finite solutions within the infrared region. The role of seagull diagrams receives particular attention, as do the identities that enforce the cancellation of all potential quadratic divergences. We stress the necessity of introducing nonperturbative massless poles in the fully dressed vertices of the theory in order to trigger the Schwinger mechanism, and explain in detail the instrumental role of these poles in maintaining the Becchi-Rouet-Stora-Tyutin symmetry at every step of the mass-generating procedure. The dynamical equation governing the evolution of the gluon mass is derived, and its solutions are determined numerically following implementation of a set of simplifying assumptions. The obtained mass function is positive definite, and exhibits a power law running that is consistent with general arguments based on the operator product expansion in the ultraviolet region. A possible connection between confinement and the presence of an inflection point in the gluon propagator is briefly discussed.

    hep-phhep-thFront.Phys.(Beijing)(2016)·103 citations
12. 12*

    From continuum QCD to hadron observables

    D. Binosi🇮🇹

    We show that the form of the renormalization group invariant quark-gluon interaction predicted by a refined nonperturbative analysis of the QCD gauge sector is in quantitative agreement with the one required for describing a wide range of hadron observables using sophisticated truncation schemes of the Schwinger-Dyson equations relevant in the matter sector.

    hep-phEPJ Web Conf.(2016)·4 citations
13. 13*

    Interpretation of the top-quark mass measurements: a theory overview

    Gennaro Corcella🇮🇹

    I discuss the theoretical interpretation of the top-quark mass, which is extracted in standard and alternative measurements at the LHC. In particular, I point out that the top mass extracted in analyses relying on the use of Monte Carlo event generators must be close to the pole mass and review recent work aiming at estimating the theoretical uncertainty.

    hep-phPoS(2016)·23 citations
14. 14*

    Scalar Dark Matter in Scale Invariant Standard Model

    Karim Ghorbani (Arak U.)🇮🇷 · Hossein Ghorbani (IPM, Tehran)🇮🇷

    We investigate single and two-component scalar dark matter scenarios in classically scale invariant standard model which is free of the hierarchy problem in the Higgs sector. We show that despite the very restricted space of parameters imposed by the scale invariance symmetry, both single and two-component scalar dark matter models overcome the direct and indirect constraints provided by the Planck/WMAP observational data and the LUX/Xenon100 experiment. We comment also on the radiative mass corrections of the classically massless scalon that plays a crucial role in our study.

    hep-phJHEP(2016)·44 citations
15. 15*

    Transverse-momentum-dependent quark splitting functions in $k_T$-factorization: real contributions

    Oleksandr Gituliar🇵🇱 · Martin Hentschinski🇲🇽 · Krzysztof Kutak🇵🇱

    We calculate transverse momentum dependent quark splitting kernels $P_{gq}$ and $P_{qq}$ within $k_T$-factorization, completing earlier results which concentrated on gluon splitting functions $P_{gg}$ and $P_{qg}$. The complete set of splitting kernels is an essential requirement for the formulation of a complete set of evolution equations for transverse momentum dependent parton distribution functions and the development of corresponding parton shower algorithms.

    hep-phJHEP(2016)·36 citations
16. 16*

    Status of the 98 - 125 GeV Higgs scenario with updated LHC-8 data

    Biplob Bhattacherjee🇮🇳 · Manimala Chakraborti🇮🇳 · Amit Chakraborty🇮🇳 · Utpal Chattopadhyay🇮🇳 · Dilip Kumar Ghosh🇮🇳

    In the context of minimal supersymmetric standard model (MSSM), we discuss the possibility of the lightest Higgs boson with mass $M_h=98$ GeV to be consistent with the $2.3\sigma$ excess observed at the LEP in the decay mode $e^{+}{e}^{-}\to Zh$, with $h\to b\bar{b}$. In the same region of the MSSM parameter space, the heavier Higgs boson $(H)$ with mass $M_H\sim 125$ GeV is required to be consistent with the latest data on Higgs coupling measurements at the end of 7 + 8 TeV LHC run with $25{\mathrm{fb}}^{-1}$ of data. While scanning the MSSM parameter space, we impose constraints coming from flavour physics, relic density of the cold dark matter as well as direct dark matter searches. We study the possibility of observing this light Higgs boson in vector boson fusion process and associated production with $W/Z$ boson at the high luminosity $(3000{\mathrm{fb}}^{-1})$ run of the 14 TeV LHC. Our analysis shows that this scenario can hardly be ruled out even at the high luminosity run of the LHC. However, the precise measurement of the Higgs signal strength ratios can play a major role to distinguish this scenario from the canonical MSSM one.

    hep-phPRD(2016)·8 citations
17. 17*

    Gravity-dominated unequal-mass black hole collisions

    Ulrich Sperhake🇬🇧 · Emanuele Berti🇺🇸 · Vitor Cardoso🇵🇹 · Frans Pretorius🇺🇸

    We continue our series of studies of high-energy collisions of black holes investigating unequal-mass, boosted head-on collisions in four dimensions. We show that the fraction of the center-of-mass energy radiated as gravitational waves becomes independent of mass ratio and approximately equal to $13\%$ at large energies. We support this conclusion with calculations using black hole perturbation theory and Smarr's zero-frequency limit approximation. These results lend strong support to the conjecture that the detailed structure of the colliding objects is irrelevant at high energies.

    ↳ gr-qchep-phhep-thPRD(2016)·24 citations
18. 18*

    Production of multistrange hadrons, light nuclei and hypertriton in central Au+Au collisions at $\sqrt{s_{NN}}=$ 11.5 and 200 GeV

    N. Shah🇨🇳 · Y. G. Ma🇨🇳 · J. H. Chen🇨🇳 · S. Zhang🇨🇳

    The production of dibaryons, light nuclei and hypertriton in the most central Au+Au collisions at $\sqrt{s_{NN}}=$ 11.5 and 200 GeV are investigated by using a naive coalescence model. The production of light nuclei is studied and found that the production rate reduces by a factor of 330 (1200) for each extra nucleon added to nuclei at $\sqrt{s_{NN}}=$ 11.5 (200) GeV. The $p_T$ integrated yield of multistrange hadrons falls exponentially as strangeness quantum number increases. We further investigate strangeness population factor $S_3,S_2$ as a function of transverse momentum as well as $\sqrt{s_{NN}}$. The calculations for $\sqrt{s_{NN}}=$ 11.5 GeV presented here will stimulate interest to carry out these measurements during the phase-II of beam energy scan program at STAR experiment.

    ↳ nucl-exhep-phPLB(2016)·42 citations
19. 19*

    Dynamical Restoration of Z_N Symmetry in SU(N)+Higgs Theories

    Minati Biswal🇮🇳 · Sanatan Digal🇮🇳 · P. S. Saumia🇮🇳

    We study the Z_N symmetry in SU(N)+Higgs theories with the Higgs field in the fundamental representation. The distributions of the Polyakov loop show that the Z_N symmetry is explicitly broken in the Higgs phase. On the other hand, inside the Higgs symmetric phase the Polyakov loop distributions and other physical observables exhibit the Z_N symmetry. This effective restoration of the Z_N symmetry changes the nature of the confinement-deconfinenement transition. We argue that the Z_N symmetry will lead to time independent topological defect solutions in the Higgs symmetric deconfined phase which will play important role at high temperatures.

    ↳ hep-lathep-phhep-thNPB(2016)·10 citations
20. 20*

    Primordial Black Holes Formation from Particle Production during Inflation

    Encieh Erfani🇮🇷

    We study the possibility that particle production during inflation can source the required power spectrum for dark matter (DM) primordial black holes (PBH) formation. We consider the scalar and the gauge quanta production in inflation models, where in the latter case, we focus in two sectors: inflaton coupled i) directly and ii) gravitationally to a $U(1)$ gauge field. We do not assume any specific potential for the inflaton field. Hence, in the gauge production case, in a model independent way we show that the non-production of DM PBHs puts stronger upper bound on the particle production parameter. Our analysis show that this bound is more stringent than the bounds from the bispectrum and the tensor-to-scalar ratio derived by gauge production in these models. In the scenario where the inflaton field coupled to a scalar field, we put an upper bound on the amplitude of the generated scalar power spectrum by non-production of PBHs. As a by-product we also show that the required scalar power spectrum for PBHs formation is lower when the density perturbations are non-Gaussian in comparison to the Gaussian density perturbations.

    ↳ astro-ph.COhep-phJCAP(2016)·39 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.