Thu·Feb 23, 2017Thursday·February 23, 2017

1. 01*

   Twist-2 matching of transverse momentum dependent distributions

   Daniel Gutierrez-Reyes🇪🇸 · Ignazio Scimemi🇪🇸 · Alexey A. Vladimirov🇩🇪

   We systematically study the large-$q_T$ (or small-$b$) matching of transverse momentum dependent (TMD) distributions to the twist-2 integrated parton distributions. Performing operator product expansion for a generic TMD operator at the next-to-leading order (NLO) we found the complete set of TMD distributions that match twist-2. These are unpolarized, helicity, transversity, pretzelosity and linearly polarized gluon distributions. The NLO matching coefficients for these distributions are presented. The pretzelosity matching coefficient is zero at the presented order, however, it is evident that it is non-zero in the following orders. This result offers a natural explanation of the small value of pretzelosity found in phenomenological fits. We also demonstrate that the cancellation of rapidity divergences by the leading order soft factor imposes the necessary requirement on the Lorentz structure of TMD operators, which is supported only by the TMD distributions of leading dynamical twist. Additionally, this requirement puts restrictions on the ${\gamma }_5$-definition in the dimensional regularization.

   hep-phhep-exnucl-exnucl-thPLB(2017)·52 citations
2. 02*

   What hadron collider is required to discover or falsify natural supersymmetry?

   Howard Baer🇺🇸 · Vernon Barger🇺🇸 · James S. Gainer🇺🇸 · Peisi Huang🇺🇸 · Michael Savoy🇺🇸 · Hasan Serce🇺🇸 · Xerxes Tata🇺🇸

   Weak scale supersymmetry (SUSY) remains a compelling extension of the Standard Model because it stabilizes the quantum corrections to the Higgs and W, Z boson masses. In natural SUSY models these corrections are, by definition, never much larger than the corresponding masses. Natural SUSY models all have an upper limit on the gluino mass, too high to lead to observable signals even at the high luminosity LHC. However, in models with gaugino mass unification, the wino is sufficiently light that supersymmetry discovery is possible in other channels over the entire natural SUSY parameter space with no worse than 3% fine-tuning. Here, we examine the SUSY reach in more general models with and without gaugino mass unification (specifically, natural generalized mirage mediation), and show that the high energy LHC (HE-LHC), a pp collider with \sqrt{s}=33 TeV, will be able to detect the SUSY signal over the entire allowed mass range. Thus, HE-LHC would either discover or conclusively falsify natural SUSY with better than 3% fine-tuning using a conservative measure that allows for correlations among the model parameters.

   hep-phPLB(2017)·28 citations
3. 03*

   Comment on "Finding the $0^{--}$ Glueball" [arXiv:1408.3995]

   Alexandr Pimikov🇨🇳 · Hee-Jung Lee🇰🇷 · Nikolai Kochelev🇷🇺

   A Comment on the Letter by C. F. Qiao and L. Tang, Phys. Rev. Lett. 113, 221601 (2014) [arXiv:1408.3995]

   hep-phPRL(2017)·17 citations
4. 04*

   Optimal observable analysis for the decay $b\to s$ plus missing energy

   Zaineb Calcuttawala🇮🇳 · Anirban Kundu🇮🇳 · Soumitra Nandi🇮🇳 · Sunando Kumar Patra🇮🇳

   The decay $b\to s\nu \bar{\nu }$ has been a neglected sibling of $b\to s{\ell }^{+}{\ell }^{-}$ because neutrinos pass undetected and hence the process offers less number of observables. We show how the decay $b\to s+$~invisible(s) can shed light, even with a limited number of observables, on possible new physics beyond the Standard Model and also show, quantitatively, the reach of future $B$ factories like SuperBelle to uncover such new physics. Depending on the operator structure of new physics, different channels may act as the best possible probe. We show, using the Optimal Observable technique, how almost the entire parameter space allowed till now can successfully be probed at a high luminosity $B$ factory.

   hep-phhep-exEPJC(2017)·10 citations
5. 05*

   Holographic QCD phase diagram with critical point from Einstein-Maxwell-dilaton dynamics

   J. Knaute🇩🇪 · R. Yaresko🇩🇪 · B. Kämpfer🇩🇪

   Supplementing the holographic Einstein-Maxwell-dilaton model of [O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D83 (2011) 086005; O. DeWolfe, S.S. Gubser, C. Rosen, Phys. Rev. D84 (2011) 126014] by input of lattice QCD data for 2+1 flavors and physical quark masses for the equation of state and quark number susceptibility at zero baryo-chemical potential we explore the resulting phase diagram over the temperature-chemical potential plane. A first-order phase transition sets in at a temperature of about 112 MeV and a baryo-chemical potential of 612 MeV. We estimate the accuracy of the critical point position in the order of approximately 5-8% by considering parameter variations and different low-temperature asymptotics for the second-order quark number susceptibility. The critical pressure as a function of the temperature has a positive slope, i.e. the entropy per baryon jumps up when crossing the phase border line from larger values of temperature/baryo-chemical potential, thus classifying the phase transition as a gas liquid one. The updated holographic model exhibits in- and outgoing isentropes in the vicinity of the first-order phase transition.

   hep-phhep-thPLB(2018)·75 citations
6. 06*

   Properties of bottomonium in a relativistic quark model

   Manjunath Bhat · Antony Prakash Monteiro · K. B. Vijaya Kumar

   The mass spectrum of $b\bar{b}$ states has been obtained using the phenomenological relativistic quark model (RQM). The Hamiltonian used in the investigation has confinement potential and confined one gluon exchange potential (COGEP). In the frame work of RQM a study of M1 and E1 radiative decays of $b\bar{b}$ states have been made. The weak decay widths in the spectator quark approximation have been estimated. An overall agreement is obtained with the experimental masses and decay widths.

   hep-phMod.Phys.Lett.A(2022)·6 citations
7. 07*

   Hadronic Vacuum Polarization in QCD and its Evaluation in the Euclidean

   Eduardo de Rafael🇫🇷

   We discuss a new technique to evaluate integrals of QCD Green's functions in the Euclidean based on their Mellin-Barnes representation. We present as a first application the evaluation of the lowest order Hadronic Vacuum Polarization (HVP) contribution to the anomalous magnetic moment of the muon $\frac{1}{2}(g_{\mu }-2{)}_{\mathrm{HVP}}\equiv a_{\mu }^{\mathrm{HVP}}$. It is shown that with a precise determination of the slope and curvature of the HVP function at the origin from lattice QCD (LQCD), one can already obtain a result for $a_{\mu }^{\mathrm{HVP}}$ which may serve as a test of the determinations based on experimental measurements of the $e^{+}{e}^{-}$ annihilation cross-section into hadrons.

   hep-phhep-latPRD(2017)·14 citations
8. 08*

   Supernova neutrinos: fast flavor conversions near the core

   Manibrata Sen🇮🇳

   Neutrino flux streaming from a supernova can undergo rapid flavor conversions almost immediately above the core. Focusing on this region, we study these fast conversions using a linear stability analysis. We find that, for realistic angular distributions of neutrinos, fast conversions can occur within a few nanoseconds in regions just above the neutrinosphere. Our results also show that neutrinos travelling towards the core make fast conversions more rapid. These conversions, if they exist, can have significant implications for supernova explosion mechanism and nucleosynthesis.

   hep-phastro-ph.HEastro-ph.SRSpringer Proc.Phys.(2018)·7 citations
9. 09*

   Multiplicity Dependence of Non-extensive Parameters for Strange and Multi-Strange Particles in Proton-Proton Collisions at $\sqrt{s}=7$ TeV at the LHC

   Arvind Khuntia🇮🇳 · Sushanta Tripathy🇮🇳 · Raghunath Sahoo🇮🇳 · Jean Cleymans🇿🇦

   The transverse momentum ($p_{\mathrm{T}}$) spectra in proton-proton collisions at $\sqrt{s}$ = 7 TeV, measured by the ALICE experiment at the LHC are analyzed with a thermodynamically consistent Tsallis distribution. The information about the freeze-out surface in terms of freeze-out volume, temperature and the non-extenisivity parameter, $q$, for $K_S^0$, $\Lambda +\bar{\Lambda }$, ${\Xi }^{-}+{\bar{\Xi }}^{+}$ and ${\Omega }^{-}+{\bar{\Omega }}^{+}$ are extracted by fitting the $p_{\mathrm{T}}$ spectra with Tsallis distribution function. The freeze-out parameters of these particles are studied as a function of charged particle multiplicity density ($d{N}_{ch}/d\eta$). In addition, we also study these parameters as a function of particle mass to see any possible mass ordering. The strange and multi-strange particles show mass ordering in volume, temperature, non-extensive parameter and also a strong dependence on multiplicity classes. It is observed that with increase in particle multiplicity, the non-extensivity parameter, $q$ decreases, which indicates the tendency of the produced system towards thermodynamic equilibration. The increase in strange particle multiplicity is observed to be due to the increase of temperature and not to the size of the freeze-out volume.

   hep-phhep-exnucl-exnucl-thEPJA(2017)·52 citations
10. 10*

    Masses of the lowest spin-0 and spin-1 meson nonets: explicit symmetry breaking effects

    Jorge Morais🇵🇹 · Brigitte Hiller🇵🇹 · Alexander A. Osipov🇷🇺

    We extend a known multi-quark three-flavor Lagrangian of the Nambu-Jona-Lasinio type, which includes a set of effective interactions proportional to the current quark masses, to include the multi-quark interactions of vector and axial-vector types. It is shown that the mass spectrum of the four low-lying meson nonets are in agreement with current phenomenological expectations. The role of the new interactions is analyzed in detail.

    hep-phPRD(2017)·8 citations
11. 11*

    Analyzing New Physics in ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$

    Chien-Thang Tran🇷🇺 · Mikhail A. Ivanov🇷🇺 · Jürgen G. Körner🇩🇪

    We discuss possible new physics (NP) effects beyond the standard model (SM) in the exclusive decays ${\bar{B}}^0\to D^{(\ast )}{\tau }^{-}{\bar{\nu }}_{\tau }$. Starting with a model-independent effective Hamiltonian including non-SM four-Fermi operators, we show how to obtain experimental constraints on different NP scenarios and investigate their effects on a large set of physical observables. The ${\bar{B}}^0\to D^{(\ast )}$ transition form factors are calculated in the full kinematic $q^2$ range by employing the covariant confined quark model developed by our group.

    hep-ph4 citations
12. 12*

    Establishing the Isolated Standard Model

    James D. Wells🇺🇸 · Zhengkang Zhang🇺🇸 · Yue Zhao🇺🇸

    The goal of this article is to initiate a discussion on what it takes to claim "there is no new physics at the weak scale," namely that the Standard Model (SM) is "isolated." The lack of discovery of beyond the SM (BSM) physics suggests that this may be the case. But to truly establish this statement requires proving all "connected" BSM theories are false, which presents a significant challenge. We propose a general approach to quantitatively assess the current status and future prospects of establishing the isolated SM (ISM), which we give a reasonable definition of. We consider broad elements of BSM theories, and show many examples where current experimental results are not sufficient to verify the ISM. In some cases, there is a clear roadmap for the future experimental program, which we outline, while in other cases, further efforts -- both theoretical and experimental -- are needed in order to robustly claim the establishment of the ISM in the absence of new physics discoveries.

    hep-phPRD(2017)·5 citations
13. 13*

    The electron plus positron spectrum from annihilation of Kaluza-Klein dark matter in the Galaxy

    Satoshi Tsuchida🇯🇵 · Masaki Mori🇯🇵

    The lightest Kaluza-Klein particle (LKP), which appears in the theory of universal extra dimensions, is one of good candidates for cold dark matter (CDM). When LKP pairs annihilate around the center of the Galaxy where CDM is concentrated, there are some modes which produce electrons and positrons as final products, and we categorize them into two components. One of them is the "Line" component, which directly annihilates into electron--positron pair. Another one is the "Continuum" component, which consists of secondarily produced electrons and positrons via some decay modes. Before reaching Earth, directions of electrons and positrons are randomized by the Galactic magnetic field, and their energies are reduced by energy loss mechanisms. We assume the LKP is in the mass range from 300 GeV to 1500 GeV. We calculate the electron plus positron spectrum after propagation in the Galactic halo to Earth, and we analyze the resulting spectrum and positron fraction. We also point out that the energy dependence of observed positron fraction is well reproduced by the mixture of "line" and "continuum" components. We can fit the electron plus positron spectrum and the positron fraction by assuming appropriate boost factors describing dark matter concentration in the Galactic halo. However, it is difficult to explain both the electron plus positron spectrum and the positron fraction by a single boost factor, if we take account of observational data obtained by AMS-02 only.

    ↳ astro-ph.HEhep-phInt.J.Mod.Phys.D(2017)·2 citations
14. 14*

    Analysis of recent CLAS data on $f_1(1285)$ photoproduction

    Xiao-Yun Wang🇨🇳 · Jun He🇨🇳

    Based on the experimental data released recently by the CLAS Collaboration, the $f_1(1285)$ photoproduction off a proton target is investigated in an effective Lagrangian approach. In our model, $s$-channel, $u$-channel, and $t$-channel Born terms are included to calculate the differential cross sections, which are compared with the recent CLAS experiment. An interpolating Reggeized treatment is applied to the $t$ channel, and it is found that the $t$-channel contribution is dominant in the $f_1(1285)$ photoproduction and the $u$-channel contribution is responsible for the enhancement at backward angles. The present calculation does not take into account any explicit $s$-channel nucleon-resonance contribution; nevertheless, our model provides a good description of the main features of the data. It suggests small couplings of the $f_1(1285)$ and the nucleon resonances in this energy region.

    ↳ nucl-thhep-phnucl-exPRD(2017)·21 citations
15. 15*

    Memory in de Sitter space and BMS-like supertranslations

    Yuta Hamada🇯🇵 · Min-Seok Seo🇰🇷 · Gary Shiu🇺🇸

    It is well known that the memory effect in flat spacetime is parametrized by the BMS supertranslation. We investigate the relation between the memory effect and diffeomorphism in de Sitter spacetime. We find that gravitational memory is parametrized by a BMS-like supertranslation in the static patch of de Sitter spacetime. We also show a diffeomorphism that corresponds to gravitational memory in the Poincare/cosmological patch. Our method does not need to assume the separation between the source and the detector to be small compared with the Hubble radius, and can potentially be applicable to other FLRW universes, as well as "ordinary memory" mediated by massive messenger particles.

    ↳ hep-thastro-ph.COgr-qchep-phPRD(2017)·39 citations
16. 16*

    Photoproduction of $\gamma p\to K^{+}{\Lambda }^{\ast }(1520)$ and decay of ${\Lambda }^{\ast }(1520)\to K^{-}p$ in the Reggeized framework

    Byung-Geel Yu🇰🇷 · Kook-Jin Kong🇰🇷

    Photoproduction of the ${\Lambda }^{\ast }(1520)$ resonance of spin-parity ${\frac{3}{2}}^{-}$ off the proton target is investigated within the Regge framework where the $t$-channel reggeization is applied for the $K(494)+K^{\ast }(892)+K_2^{\ast }(1430)$ exchanges in the Born amplitude. The present model is based on the two basic ingredients; the one is the minimal gauge prescription for the convergence of the reaction and the other is the role of the $K_2^{\ast }$ crucial to be consistent with high energy data. The cross sections for the total, differential and photon polarization asymmetry are reproduced without fit parameters and compared with existing data. The LAMP2 and LEPS measurements of the angular distribution of the $K^{-}$ in the ${\Lambda }^{\ast }(1520)\to K^{-}p$ decay are investigated and found to be dominated by the decay of ${\Lambda }^{\ast }$ with helicity $\pm 3/2$ based on the analysis of the density matrix elements related. Detailed discussion on the density matrix elements is given to clarify the analysis of the observable. The reaction mechanism is featured by the dominance of the contact term with the $K$ and $K_2^{\ast }$ exchanges following in the low energy region. The $K^{\ast }$ exchange appears in minor role. At high energies beyond $E_{\gamma }\approx 5$ GeV the role of $K_2^{\ast }$ exchange leads over other exchanges in the reaction process.

    ↳ nucl-thhep-phPRC(2017)·13 citations
17. 17*

    Particle distribution in intense fields in a light-front Hamiltonian approach

    Guangyao Chen🇺🇸 · Xingbo Zhao🇨🇳 · Yang Li🇺🇸 · Kirill Tuchin🇺🇸 · James P. Vary🇺🇸

    We study the real-time evolution of an electron influenced by intense electromagnetic fields using the time-dependent basis light-front quantization (tBLFQ) framework. We focus on demonstrating the non-perturbative feature of the tBLFQ approach through a realistic application of the strong coupling QED problem, in which the electromagnetic fields are generated by an ultra-relativistic nucleus. We calculate transitions of an electron influenced by such electromagnetic fields and we show agreement with light-front perturbation theory when the atomic number of the nucleus is small. We compare tBLFQ simulations with perturbative calculations for nuclei with different atomic numbers, and obtain the significant higher-order contributions for heavy nuclei. The simulated real-time evolution of the momentum distribution of an electron evolving inside the strong electromagnetic fields exhibits significant non-perturbative corrections comparing to light-front perturbation theory calculations. The formalism used in this investigation can be extended to QCD problems in heavy ion collisions and electron ion collisions.

    ↳ nucl-thhep-phhep-thPRD(2017)·18 citations
18. 18*

    The Core-Collapse Supernova Explosion Mechanism

    B. Müller (Queen's University Belfast, Monash University)🇬🇧

    The explosion mechanism of core-collapse supernovae is a long-standing problem in stellar astrophysics. We briefly outline the main contenders for a solution and review recent efforts to model core-collapse supernova explosions by means of multi-dimensional simulations. We discuss several suggestions for solving the problem of missing or delayed neutrino-driven explosions in three-dimensional supernova models, including -- among others -- variations in the microphysics and large seed perturbations in convective burning shells. Focusing on the neutrino-driven mechanism, we summarise currents efforts to predict supernova explosion and remnant properties based on first-principle models and on more phenomenological approaches.

    ↳ astro-ph.SRastro-ph.HEhep-phnucl-thIAU Symp.(2016)·14 citations
19. 19*

    The effect upon neutrinos of core-collapse supernova accretion phase turbulence

    James P. Kneller🇺🇸 · Mithi de los Reyes🇬🇧

    During the accretion phase of a core-collapse supernovae, large amplitude turbulence is generated by the combination of the standing accretion shock instability and convection driven by neutrino heating. The turbulence directly affects the dynamics of the explosion, but there is also the possibility of an additional, indirect, feedback mechanism due to the effect turbulence can have upon neutrino flavor evolution and thus the neutrino heating. In this paper we consider the effect of turbulence during the accretion phase upon neutrino evolution, both numerically and analytically. Adopting representative supernova profiles taken from the accretion phase of a supernova simulation, we find the numerical calculations exhibit no effect from turbulence. We explain this absence using two analytic descriptions: the Stimulated Transition model and the Distorted Phase Effect model. In the Stimulated Transition model turbulence effects depend upon six different lengthscales, and three criteria must be satisfied between them if one is to observe a change in the flavor evolution due to Stimulated Transition. We further demonstrate that the Distorted Phase Effect depends upon the presence of multiple semi-adiabatic MSW resonances or discontinuities that also can be expressed as a relationship between three of the same lengthscales. When we examine the supernova profiles used in the numerical calculations we find the three Stimulated Transition criteria cannot be satisfied, independent of the form of the turbulence power spectrum, and that the same supernova profiles lack the multiple semi-adiabatic MSW resonances or discontinuities necessary to produce a Distorted Phase Effect. Thus we conclude that even though large amplitude turbulence is present in supernova during the accretion phase, it has no effect upon neutrino flavor evolution.

    ↳ astro-ph.HEastro-ph.SRhep-phnucl-thJ.Phys.G(2017)·9 citations
20. 20*

    Fermions in worldline holography

    Dennis D. Dietrich🇩🇪 · Adrian Koenigstein🇩🇪

    We analyse the worldline holographic framework for fermions. Worldline holography is based on the observation that in the worldline approach to quantum field theory, sources of a quantum field theory over Mink${}_4$ naturally form a field theory over AdS${}_5$ to all orders in the elementary fields and in the sources. Schwinger's proper time of the worldline formalism automatically appears with the physical four spacetime dimensions in an AdS${}_5$ geometry. The worldline holographic effective action in general and the proper-time profiles of the sources in particular solve a renormalisation group equation. By taking into account sources up to spin one, we reconstruct seminal holographic models. Considering spin two confirms AdS${}_5$ as consistent background.

    ↳ hep-thhep-phnucl-thPRD(2017)·1 citation

* 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.