Wed·Apr 20, 2016Wednesday·April 20, 2016

1. 01*

   The MV Model of the Color Glass Condensate for a Finite Number of Sources Including Coulomb Interactions

   Larry McLerran🇺🇸 · Vladimir V. Skokov🇺🇸

   We modify the McLerran-Venugopalan model to include only a finite number of sources of color charge. We argue that Coulombic interactions between these color charges generates a source-source correlation function that properly includes the effects of color charge screening, a generalization of Debye screening for the Color Glass Condensate. Such a model may be useful for computing angular harmonics of flow measured in high energy hadron collisions for small systems. In this paper we provide a basic formulation of the problem on a lattice.

   hep-phNPA(2017)·2 citations
2. 02*

   New Forces and the 750 GeV Resonance

   Michael Duerr🇩🇪 · Pavel Fileviez Perez🇩🇪 · Juri Smirnov🇩🇪

   Recently, the ATLAS and CMS collaborations have pointed out the possible existence of a new resonance with a mass around 750 GeV. We investigate the possibility to identify this new resonance with a spin zero field responsible for the breaking of a new gauge symmetry. We focus on a simple theory where the baryon number is a local symmetry spontaneously broken at the low scale. In this context new vector-like quarks are needed to cancel all baryonic anomalies and define the production mechanism and decays of the new Higgs at the LHC. Assuming the existence of the new Higgs with a mass of 750 GeV at the LHC we find an upper bound on the symmetry breaking scale. Therefore, one expects that a new force associated with baryon number could be discovered at the LHC.

   hep-phhep-ex14 citations
3. 03*

   The lightest visible-sector supersymmetric particle is likely to be unstable

   Bobby S. Acharya🇬🇧 · Sebastian A. R. Ellis🇺🇸 · Gordon L. Kane🇺🇸 · Brent D. Nelson🇺🇸 · Malcolm J. Perry🇬🇧

   We argue, based on typical properties of known solutions of string/$M$-theory, that the lightest supersymmetric particle of the visible sector will not be stable. In other words, dark matter is {\em not} a particle with Standard Model quantum numbers, such as a WIMP. The argument is simple and based on the typical occurrence of a) hidden sectors, b) interactions between the Standard Model (visible) sector and these hidden sectors, and c) the lack of an argument against massive neutral hidden sector particles being lighter than the lightest visible supersymmetric particle. These conclusions do not rely on arguments such as R-parity violation.

   hep-phhep-thPRL(2016)·67 citations
4. 04*

   The Higgs Portal and Cosmology

   Ketevi Assamagan🇺🇸 · Chien-Yi Chen🇨🇦 · John Paul Chou🇺🇸 · David Curtin🇺🇸 · Michael A. Fedderke🇺🇸 · Yuri Gershtein🇺🇸 · Xiao-Gang He🇨🇳 · Markus Klute🇺🇸 · Jonathan Kozaczuk🇨🇦 · Ashutosh Kotwal🇺🇸 · Steven Lowette🇧🇪 · Jose Miguel No🇬🇧 and 10 other authors

   Higgs portal interactions provide a simple mechanism for addressing two open problems in cosmology: dark matter and the baryon asymmetry. In the latter instance, Higgs portal interactions may contain the ingredients for a strong first order electroweak phase transition as well as new CP-violating interactions as needed for electroweak baryogenesis. These interactions may also allow for a viable dark matter candidate. We survey the opportunities for probing the Higgs portal as it relates to these questions in cosmology at the LHC and possible future colliders.

   hep-ph31 citations
5. 05*

   Minimal Dilaton Model and the Diphoton Excess

   Bakul Agarwal🇺🇸 · Joshua Isaacson🇺🇸 · Kirtimaan A. Mohan🇺🇸

   In light of the recent 750 GeV diphoton excesses reported by the ATLAS and CMS collaborations, we investigate the possibility of explaining this excess using the Minimal Dilaton Model. We find that this model is able to explain the observed excess with the presence of additional top partner(s), with same charge as the top quark, but with mass in the TeV region. First, we constrain model parameters using in addition to the 750 GeV diphoton signal strength, precision electroweak tests, single top production measurements, as well as Higgs signal strength data collected in the earlier runs of the LHC. In addition we discuss interesting phenomenolgy that could arise in this model, relevant for future runs of the LHC.

   hep-phhep-exPRD(2016)·11 citations
6. 06*

   The Higgs mass in the CP violating MSSM, NMSSM, and beyond

   Mark D. Goodsell🇫🇷 · Florian Staub🇨🇭

   We discuss the automatised calculation of the Higgs mass in renormalisable supersymmetric models with complex parameters at the two-loop level. Our setup is based on the public codes SARAH and SPheno, which can now compute the two-loop corrections to masses of all neutral scalars in such theories. The generic ansatz for these calculations and the handling of the `Goldstone Boson catastrophe' is described. It is shown that we find perfect agreement with other existing two-loop calculations performed in the DR-bar scheme. We also use the functionality to derive results for the MSSM and NMSSM not available before: the Higgs mass in the constrained version of the complex MSSM, and the impact of CP phases in the two-loop corrections beyond order alpha-strong alpha-top for the scale invariant NMSSM are briefly analysed.

   hep-phEPJC(2017)·63 citations
7. 07*

   Ratio between two $\Lambda$ and $\bar{\Lambda }$ production mechanisms in $p$ scattering

   B. Hoeneisen🇪🇨

   We consider $\Lambda$ and $\bar{\Lambda }$ production in a wide range of proton scattering experiments. The produced $\Lambda$ and $\bar{\Lambda }$ may or may not contain a diquark remnant of the beam proton. The ratio of these two production mechanisms is found to be a simple universal function $r=[\kappa /(y_p-y){]}^i$ of the rapidity difference $y_p-y$ of the beam proton and the produced $\Lambda$ or $\bar{\Lambda }$, valid over four orders of magnitude, from $r\approx 0.01$ to $r\approx 100$, with $\kappa =2.86\pm 0.03\pm 0.07$, and $i=4.39\pm 0.06\pm 0.15$.

   hep-phnucl-thPLB(2016)·1 citation
8. 08*

   Investigating light NMSSM pseudoscalar states with boosted ditau tagging

   Eric Conte🇫🇷 · Benjamin Fuks🇫🇷 · Jun Guo🇨🇳 · Jinmian Li🇦🇺 · Anthony G. Williams🇦🇺

   We study a class of realizations of the Next-to-Minimal Supersymmetric Standard Model that is motivated by dark matter and Higgs data, and in which the lightest pseudoscalar Higgs boson mass is smaller than twice the bottom quark mass and greater than twice the tau lepton mass. In such scenarios, the lightest pseudoscalar Higgs boson can be copiously produced at the LHC from the decay of heavier superpartners and will dominantly further decay into a pair of tau leptons that is generally boosted. We make use of a boosted object tagging technique designed to tag such a ditau jet, and estimate the sensitivity of the LHC to the considered supersymmetric scenarios with 20 to 50~fb${}^{-1}$ of proton-proton collisions at a center-of-mass energy of 13~TeV.

   hep-phhep-exJHEP(2016)·28 citations
9. 09*

   Nature of the X(5568) : a critical Laplace sum rule analysis at N2LO

   R. Albuquerque (FAT, UERJ, Rio de Janeiro)🇧🇷 · S. Narison (LUPM, Montpellier)🇫🇷 · A. Rabemananjara (iHEPMAD, Antananarivo)🇲🇬 · D. Rabetiarivony (iHEPMAD, Antananarivo)🇲🇬

   We scrutinize recent QCD spectral sum rules (QSSR) results to lowest order (LO) predicting the masses of the BK molecule and (su)\bar(bd) four-quark states. We improve these results by adding NLO and N2LO corrections to the PT contributions giving a more precise meaning on the b-quark mass definition used in the analysis. We extract our optimal predictions using Laplace sum rule (LSR) within the standard stability criteria versus the changes of the external free parameters (\tau-sum rule variable, t_c continuum threshold and subtraction constant \mu). The smallness of the higher order PT corrections justifies (a posteriori) the LO order results + the uses of the ambiguous heavy quark mass to that order. However, our predicted spectra in the range (5173\sim 5226) MeV, summarized in Table 7, for exotic hadrons built with four different flavours (buds), do not support some previous interpretations of the D0 candidate[1], X(5568), as a pure molecule or a four-quark state. If experimentally confirmed, it could result from their mixing with an angle: sin 2\theta\approx 0.15. One can also scan the region (2327~ 2444) MeV (where the D*_{s0}(2317) might be a good candidate) and the one (5173~ 5226) MeV for detecting these (cuds) and (buds) unmixed exotic hadrons (if any) via, eventually, their radiative or \pi+hadrons decays.

   hep-phhep-exhep-latInt.J.Mod.Phys.A(2016)·50 citations
10. 10*

    The Scale-Invariant Scotogenic Model

    Amine Ahriche🇩🇿 · Kristian L. McDonald🇦🇺 · Salah Nasri🇦🇪

    We investigate a minimal scale-invariant implementation of the scotogenic model and show that viable electroweak symmetry breaking can occur while simultaneously generating one-loop neutrino masses and the dark matter relic abundance. The model predicts the existence of a singlet scalar (dilaton) that plays the dual roles of triggering electroweak symmetry breaking and sourcing lepton number violation. Important constraints are studied, including those from lepton flavor violating effects and dark matter direct-detection experiments. The latter turn out to be somewhat severe, already excluding large regions of parameter space. None the less, viable regions of parameter space are found, corresponding to dark matter masses below (roughly) 10 GeV and above 200 GeV.

    hep-phJHEP(2016)·77 citations
11. 11*

    Is the exotic $X(5568)$ a bound state?

    Xiaoyun Chen🇨🇳 · Jialun Ping🇨🇳

    Stimulated by the recent observation of the exotic $X(5568)$ state by D0 Collaboration, we study the four-quark system $us\bar{b}\bar{d}$ with quantum numbers $J^P=0^{+}$ in the framework of chiral quark model. Two structures, diquark-antidiquark and meson-meson, with all possible color configurations are investigated by using Gaussian expansion method. The results show that energies of the tetraquark states with diquark-antiquark structure are too high to the candidate of $X(5568)$, and no molecular structure can be formed in our calculations. The calculation is also extended to the four-quark system $us\bar{c}\bar{d}$ and the same results as that of $us\bar{b}\bar{d}$ are obtained.

    hep-phEPJC(2016)·39 citations
12. 12*

    Lepton mixing patterns from the group $\Sigma (36\times 3)$ with a generalized CP transformation

    Shu-jun Rong🇨🇳

    The group $\Sigma (36\times 3)$ with the generalized CP transformation is introduced to predict the mixing pattern of leptons. Various combinations of abelian residual flavor symmetries with CP transformations are surveyed. Six mixing patterns could accommodate the fit data of neutrinos oscillation at $3\sigma$ level. Among them, two patterns predict the nontrivial Dirac CP phase, around $\pm 57^{\circ }$ or $\pm 123^{\circ }$, which is in accordance with the result of the literature and the recent fit data. Furthermore, one pattern could satisfy the experimental constraints at $1\sigma$ level.

    hep-phPRD(2017)·22 citations
13. 13*

    A Lagrangian formulation of relativistic Israel-Stewart hydrodynamics

    Giorgio Torrieri🇧🇷 · David Montenegro🇧🇷

    We rederive relativistic hydrodynamics as a Lagrangian effective theory using the doubled coordinates technique, allowing us to include dissipative terms. We include Navier-Stokes shear and bulk terms, as well as Israel-Stewart relaxation time terms, within this formalism. We show how the inclusion of shear viscosity, and the requirement of a bounded energy-momentum "vacuum", forces the inclusion of the Israel-Stewart term into the theory, thereby providing a justification for the origin and uniqueness of these terms.

    ↳ hep-thhep-phnucl-thphysics.flu-dynPRD(2016)·32 citations
14. 14*

    Constraints on primordial black holes from Galactic gamma-ray background

    B. J. Carr🇬🇧 · Kazunori Kohri🇯🇵 · Yuuiti Sendouda🇯🇵 · Jun'ichi Yokoyama🇯🇵

    The fraction of the Universe going into primordial black holes (PBHs) with initial mass M_* \approx 5 \times 10^{14} g, such that they are evaporating at the present epoch, is strongly constrained by observations of both the extragalactic and Galactic gamma-ray backgrounds. However, while the dominant contribution to the extragalactic background comes from the time-integrated emission of PBHs with initial mass M_*, the Galactic background is dominated by the instantaneous emission of those with initial mass slightly larger than M_* and current mass below M_*. Also, the instantaneous emission of PBHs smaller than 0.4 M_* mostly comprises secondary particles produced by the decay of directly emitted quark and gluon jets. These points were missed in the earlier analysis by Lehoucq et al. using EGRET data. For a monochromatic PBH mass function, with initial mass (1+\mu) M_* and \mu << 1, the current mass is (3\mu)^{1/3} M_* and the Galactic background constrains the fraction of the Universe going into PBHs as a function of \mu. However, the initial mass function cannot be precisely monochromatic and even a tiny spread of mass around M_* would generate a current low-mass tail of PBHs below M_*. This tail would be the main contributor to the Galactic background, so we consider its form and the associated constraints for a variety of scenarios with both extended and nearly-monochromatic initial mass functions. In particular, we consider a scenario in which the PBHs form from critical collapse and have a mass function which peaks well above M_*. In this case, the largest PBHs could provide the dark matter without the M_* ones exceeding the gamma-ray background limits.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2016)·206 citations
15. 15*

    What lattice theorists can do for superstring/M-theory

    Masanori Hanada🇺🇸

    The gauge/gravity duality provides us with nonperturbative formulation of superstring/M-theory. Although inputs from gauge theory side are crucial for answering many deep questions associated with quantum gravitational aspects of superstring/M-theory, many of the important problems have evaded analytic approaches. For them, lattice gauge theory is the only hope at this moment. In this review I give a list of such problems, putting emphasis on problems within reach in a five-year span, including both Euclidean and real-time simulations.

    ↳ hep-lathep-phhep-thInt.J.Mod.Phys.A(2016)·42 citations
16. 16*

    Model independent analysis of nearly Lévy correlations

    T. Novák🇭🇺 · T. Csörgő🇭🇺 · H. C. Eggers🇿🇦 · M. de Kock🇿🇦

    A model-independent method for the analysis of the two-particle short-range correlations is presented, that can be utilized to describe e.g. Bose-Einstein (HBT), dynamical (ridge) or other correlation functions, that have a nearly Lévy or streched exponential shape. For the special case of Lévy exponent alpha = 1, the earlier Laguerre expansions are recovered, for the alpha = 2 special case, a new expansion method is obtained for nearly Gaussian correlation functions. Multi-dimensional Lévy expansions are also introduced and their potential application to analyze rigde correlation data is discussed.

    ↳ physics.data-anhep-exhep-phnucl-ex+1Acta Phys.Polon.Supp.(2016)·15 citations
17. 17*

    Propagation of heavy baryons in heavy-ion collisions

    Santosh K. Das🇮🇹 · Juan M. Torres-Rincon🇫🇷 · Laura Tolos🇪🇸 · Vincenzo Minissale🇮🇹 · Francesco Scardina🇮🇹 · Vincenzo Greco🇮🇹

    The drag and diffusion coefficients of heavy baryons (${\Lambda }_c$ and ${\Lambda }_b$) in the hadronic phase created in the latter stage of the heavy-ion collisions at RHIC and LHC energies have been evaluated recently. In this work we compute some experimental observables, such as the nuclear suppression factor $R_{AA}$ and the elliptic flow $v_2$ of heavy baryons at RHIC and LHC energies, highlighting the role of the hadronic phase contribution to these observables, which are going to be measured at Run 3 of LHC. For the time evolution of the heavy quarks in the QGP and heavy baryons in the hadronic phase we use the Langevin dynamics. For the hadronization of the heavy quarks to heavy baryons we employ Peterson fragmentation functions. We observe a strong suppression of both the ${\Lambda }_c$ and ${\Lambda }_b$. We find that the hadronic medium has a sizable impact on the heavy-baryon elliptic flow whereas the impact of hadronic medium rescattering is almost unnoticeable on the nuclear suppression factor. We evaluate the ${\Lambda }_c/D$ ratio at RHIC and LHC. We find that ${\Lambda }_c/D$ ratio remain unaffected due to the hadronic phase rescattering which enable it as a nobel probe of QGP phase dynamics along with its hadronization.

    ↳ nucl-thhep-phnucl-exPRD(2016)·63 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.