Fri·Aug 14, 2015Friday·August 14, 2015

1. 01*

   Dark matter and neutrino masses from a scale-invariant multi-Higgs portal

   Alexandros Karam🇬🇷 · Kyriakos Tamvakis🇬🇷

   We consider a classically scale invariant version of the Standard Model, extended by an extra dark $SU(2{)}_X$ gauge group. Apart from the dark gauge bosons and a dark scalar doublet which is coupled to the Standard Model Higgs through a portal coupling, we incorporate right-handed neutrinos and an additional real singlet scalar field. After symmetry breaking à la Coleman-Weinberg, we examine the multi-Higgs sector and impose theoretical and experimental constraints. In addition, by computing the dark matter relic abundance and the spin-independent scattering cross section off a nucleon we determine the viable dark matter mass range in accordance with present limits. The model can be tested in the near future by collider experiments and direct detection searches such as XENON 1T.

   hep-phPRD(2015)·163 citations
2. 02*

   Discovering Inelastic Thermal-Relic Dark Matter at Colliders

   Eder Izaguirre🇨🇦 · Gordan Krnjaic🇨🇦 · Brian Shuve🇨🇦

   Dark Matter particles with inelastic interactions are ubiquitous in extensions of the Standard Model, yet remain challenging to fully probe with existing strategies. We propose a series of powerful searches at hadron and lepton colliders that are sensitive to inelastic dark matter dynamics. In representative models featuring either a massive dark photon or a magnetic dipole interaction, we find that the LHC and BaBar could offer strong sensitivity to the thermal-relic dark matter parameter space for dark matter masses between ~100 MeV-100 GeV and fractional mass-splittings above the percent level; future searches at Belle II with a dedicated monophoton trigger could also offer sensitivity to thermal-relic scenarios with masses below a few GeV. Thermal scenarios with either larger masses or splittings are largely ruled out; lower masses remain viable yet may be accessible with other search strategies.

   hep-phastro-ph.COhep-exPRD(2016)·160 citations
3. 03*

   Loop level constraints on Seesaw neutrino mixing

   Enrique Fernandez-Martinez🇪🇸 · Josu Hernandez-Garcia🇪🇸 · Jacobo Lopez-Pavon🇮🇹 · Michele Lucente🇫🇷

   We perform a detailed study of the importance of loop corrections when deriving bounds on heavy-active neutrino mixing in the context of general Seesaw mechanisms with extra heavy right-handed neutrinos. We find that, for low-scale Seesaws with an approximate $B-L$ symmetry characterized by electroweak scale Majorana masses and large Yukawas, loop corrections could indeed become relevant in a small part of the parameter space. Previous results in the literature showed that a partial cancellation between these important loop corrections and the tree level contributions could relax some constraints and lead to qualitatively different results upon their inclusion. However, we find that this cancellation can only take place in presence of large violations of the $B-L$ symmetry, that lead to unacceptably large contributions to the light neutrino masses at loop level. Thus, when we restrict our analysis of the key observables to an approximate $B-L$ symmetry so as to recover the correct values for neutrino masses, we always find loop corrections to be negligible in the regions of the parameter space preferred by data.

   hep-phJHEP(2015)·91 citations
4. 04*

   Probing CP violation systematically in differential distributions

   Gauthier Durieux🇺🇸 · Yuval Grossman🇺🇸

   We revisit the topic of triple-product asymmetries which probe CP violation through differential distributions. We construct distributions with well-defined discrete symmetry properties and characterize the asymmetries formed upon them. It is stressed that the simplest asymmetries may not be optimal. We explore systematic generalizations having limited reliance on the process dynamics and phase-space parametrization. They exploit larger fractions of the information contained in differential distributions and may lead to increased sensitivities to CP violation. Our detailed treatment of the case of spinless four-body decays paves the way for further experimental studies.

   hep-phhep-exPRD(2015)·79 citations
5. 05*

   Nonequilibrium fixed points in longitudinally expanding scalar theories: infrared cascade, Bose condensation and a challenge for kinetic theory

   J. Berges🇩🇪 · K. Boguslavski🇩🇪 · S. Schlichting🇺🇸 · R. Venugopalan🇺🇸

   In Phys. Rev. Lett. 114 (2015) 6, 061601, we reported on a new universality class for longitudinally expanding systems, encompassing strongly correlated non-Abelian plasmas and $N$-component self-interacting scalar field theories. Using classical-statistical methods, we showed that these systems share the same self-similar scaling properties for a wide range of momenta in a limit where particles are weakly coupled but their occupancy is high. Here we significantly expand on our previous work and delineate two further self-similar regimes. One of these occurs in the deep infrared (IR) regime of very high occupancies, where the nonequilibrium dynamics leads to the formation of a Bose-Einstein Condensate. The universal IR scaling exponents and the spectral index characterizing the isotropic IR distributions are described by an effective theory derived from a systematic large-$N$ expansion at next-to-leading order. Remarkably, this effective theory can be cast as a vertex-resummed kinetic theory. The other novel self-similar regime occurs close to the hard physical scale of the theory, and sets in only at later times. We argue that the important role of the infrared dynamics ensures that key features of our results for scalar and gauge theories cannot be reproduced consistently in conventional kinetic theory frameworks.

   hep-phnucl-thPRD(2015)·55 citations
6. 06*

   Neutrino oscillations in accelerated states

   Dharam Vir Ahluwalia🇮🇳 · Lance Labun🇺🇸 · Giorgio Torrieri🇧🇷

   We discuss the inverse $\beta$-decay of accelerated protons in the context of neutrino oscillations. The process $p\to n{\ell }^{+}{\nu }_{\ell }$ is kinematically allowed because the accelerating field provides the rest energy difference between initial and final states. The rate of $p\to n$ conversions can be evaluated in either the laboratory frame (where the proton is accelerating) or the co-moving frame (where the proton is at rest and interacts with an effective thermal bath of $\ell$ and ${\nu }_{\ell }$ due to the Unruh effect). By explicit calculation, we show the rates in the two frames disagree when taking into account neutrino oscillations, because the weak interaction couples to charge eigenstates whereas gravity couples to neutrino mass eigenstates. The contradiction could be resolved experimentally, potentially yielding new information on the origins of neutrino masses.

   hep-phhep-thEPJA(2016)·39 citations
7. 07*

   Large Transverse Momenta and Tsallis Thermodynamics

   J. Cleymans🇿🇦 · M. D. Azmi🇮🇳

   The charged particle transverse momentum ($p_T$) spectra measured by the ATLAS and CMS collaborations in proton - proton collisions at sqrt(s) = 0.9 and 7 TeV have been studied using Tsallis thermodynamics. A thermodynamically consistent form of the Tsallis distribution is used for fitting the transverse momentum spectra at mid-rapidity. It is found that the fits based on the proposed distribution provide an excellent description over 14 orders of magnitude with $p_T$ values up to 200 GeV/c.

   hep-phJ.Phys.Conf.Ser.(2016)·9 citations
8. 08*

   Modification of Fox-Wolfram Moments for Hadron Colliders

   Laurence Anthony Spiller🇦🇺

   Collisions of composite particles impose an arbitrary boost in the longitudinal direction on a given event. This implies that the centre-of-mass frame at hadron colliders is undetermined for processes with missing energy in the final state. This motivates the modification of the Fox-Wolfram moments such that the moments for a given event are identical when viewed in the lab or centre-of-mass frame of the beam. The resulting moments are invariant under rotations in the plane transverse to the beam and boosts parallel to the beam. These moments are then used to demonstrate improved signal separation in the channel where the Higgs decays to two b-quarks while being produced in association with a vector boson.

   hep-phhep-exJHEP(2016)·5 citations
9. 09*

   Appearance-Disappearance Relation in 3+$N_s$ Short-Baseline Neutrino Oscillations

   C. Giunti🇮🇹 · E. M. Zavanin🇧🇷

   We derive the relation between the amplitudes of short-baseline appearance and disappearance oscillations in 3+$N_s$ neutrino mixing schemes which is the origin of the appearance-disappearance tension that is found from the analysis of the existing data in any 3+$N_s$ neutrino mixing scheme. We illustrate the power of the relation to reveal the appearance-disappearance tension in the cases of 3+1 and 3+2 mixing using the results of global fits of short-baseline neutrino oscillation data.

   hep-phastro-ph.COhep-exMod.Phys.Lett.A(2015)·36 citations
10. 10*

    Discriminative phenomenological features of scale invariant models for electroweak symmetry breaking

    Katsuya Hashino🇯🇵 · Shinya Kanemura🇯🇵 · Yuta Orikasa🇰🇷

    Classical scale invariance (CSI) may be one of the solutions for the hierarchy problem. Realistic models for electroweak symmetry breaking based on CSI require extended scalar sectors without mass terms, and the electroweak symmetry is broken dynamically at the quantum level by the Coleman-Weinberg mechanism. We discuss discriminative features of these models. First, using the experimental value of the mass of the discovered Higgs boson $h(125)$, we obtain an upper bound on the mass of the lightest additional scalar boson (~543 GeV), which does not depend on its isospin and hypercharge. Second, a discriminative prediction on the Higgs-photon-photon coupling is given as a function of the number of charged scalar bosons, by which we can narrow down possible models using current and future data for the di-photon decay of $h(125)$. Finally, for the triple Higgs boson coupling a large deviation (~ +70 %) from the SM prediction is universally predicted, which is independent of masses, quantum numbers and even the number of additional scalars. These models based on CSI can be well tested at LHC Run II and at future lepton colliders.

    hep-phPLB(2016)·60 citations
11. 11*

    Exploring the CP-violating NMSSM: EDM Constraints and Phenomenology

    S.F. King🇬🇧 · M. Muhlleitner🇩🇪 · R. Nevzorov🇦🇺 · K. Walz🇩🇪

    The Next-to-Minimal Supersymmetric extension of the Standard Model (NMSSM) features extra new sources for CP violation. In contrast to the MSSM CP violation can already occur at tree level in the Higgs sector. We investigate the range of possible allowed CP-violating phases by taking into account the constraints arising from the measurements of the Electric Dipole Moments (EDMs) and the latest LHC Higgs data. Our analysis shows that large CP-violating phases, that are NMSSM-specific, are not in conflict with the EDMs. They are dominantly constrained by the Higgs data in this case. We use our results to investigate the prospects of measuring CP violation through the combined measurement of Higgs rates, on the one hand, and in observables based on CP-violating Higgs couplings to tau leptons on the other hand.

    hep-phNPB(2015)·60 citations
12. 12*

    Slowly rotating black hole solutions in Horndeski gravity

    Andrea Maselli🇺🇸 · Hector O. Silva🇺🇸 · Masato Minamitsuji🇵🇹 · Emanuele Berti🇺🇸

    We study black hole solutions at first order in the Hartle-Thorne slow-rotation approximation in Horndeski gravity theories. We derive the equations of motion including also cases where the scalar depends linearly on time. In the Hartle-Thorne formalism, all first-order rotational corrections are described by a single frame-dragging function. We show that the frame-dragging function is exactly the same as in general relativity for all known black hole solutions in shift symmetric Horndeski theories, with the exception of theories with a linear coupling to the Gauss-Bonnet invariant. Our results extend previous no-hair theorems for a broad class of Horndeski gravity theories.

    ↳ gr-qcastro-ph.COhep-phhep-thPRD(2015)·111 citations
13. 13*

    A look inside charmed-strange baryons from lattice QCD

    K. U. Can🇯🇵 · G. Erkol🇹🇷 · M. Oka🇯🇵 · T. T. Takahashi🇯🇵

    The electromagnetic form factors of the spin-3/2 $\Omega$ baryons, namely $\Omega$, ${\Omega }_c^{\ast }$, ${\Omega }_{cc}^{\ast }$ and ${\Omega }_{ccc}$, are calculated in full QCD on $32^3\times 64$ PACS-CS lattices with a pion mass of 156(9) MeV. The electric charge radii and magnetic moments from the $E0$ and $M1$ multipole form factors are extracted. Results for the electric quadrupole form factors, $E2$, are also given. Quark sector contributions are computed individually for each observable and then combined to obtain the baryon properties. We find that the charm quark contributions are systematically smaller than the strange-quark contributions in the case of the charge radii and magnetic moments. $E2$ moments of the ${\Omega }_{cc}^{\ast }$ and ${\Omega }_{ccc}$ provide a statistically significant data to conclude that their electric charge distributions are deformed to an oblate shape. Properties of the spin-1/2 ${\Omega }_c$ and ${\Omega }_{cc}$ baryons are also computed and a thorough comparison is given. This complete study gives valuable hints about the heavy-quark dynamics in charmed hadrons.

    ↳ hep-lathep-phPRD(2015)·74 citations
14. 14*

    A remark on the asymptotic form of BPS multi-dyon solutions and their conserved charges

    C. P. Constantinidis🇧🇷 · L. A. Ferreira🇧🇷 · G. Luchini🇧🇷

    We evaluate the gauge invariant, dynamically conserved charges, recently obtained from the integral form of the Yang-Mills equations, for the BPS multi-dyon solutions of a Yang-Mills-Higgs theory associated to any compact semi-simple gauge group G. Those charges are shown to correspond to the eigenvalues of the next-to-leading term of the asymptotic form of the Higgs field at spatial infinity, and so coinciding with the usual topological charges of those solutions. Such results show that many of the topological charges considered in the literature are in fact dynamical charges, which conservation follows from the global properties of classical Yang-Mills theories encoded into their integral dynamical equations. The conservation of those charges can not be obtained from the differential form of Yang-Mills equations.

    ↳ hep-thhep-phnlin.SIJHEP(2015)·4 citations
15. 15*

    Towards a Quantum Theory of Solitons

    Gia Dvali🇩🇪 · Cesar Gomez🇩🇪 · Lukas Gruending🇩🇪 · Tehseen Rug🇩🇪

    We formulate a quantum coherent state picture for topological and non-topological solitons. We recognize that the topological charge arises from the infinite occupation number of zero momentum quanta flowing in one direction. Thus, the Noether charge of microscopic constituents gives rise to a topological charge in the macroscopic description. This fact explains the conservation of topological charge from the basic properties of coherent states. It also shows that no such conservation exists for non-topological solitons, which have finite mean occupation number. Consequently, they can have an exponentially-small but non-zero overlap with the vacuum, leading to vacuum instability. This amplitude can be interpreted as a coherent state description of false vacuum decay. Next we show that we can represent topological solitons as a convolution of two sectors that carry information about topology and energy separately, which makes their difference very transparent. Finally, we show how interaction among the solitons can be understood from basic properties of quantum coherent states.

    ↳ hep-thhep-phquant-phNPB(2015)·40 citations
16. 16*

    Exclusive ${\rho }^0$ Meson Photoproduction with a Leading Neutron at HERA

    H1 Collaboration

    A first measurement is presented of exclusive photoproduction of ${\rho }^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years $2006$ and $2007$ at a centre-of-mass energy of $\sqrt{s}=319$ GeV and correspond to an integrated luminosity of $1.16$ pb${}^{-1}$. The ${\rho }^0$ mesons with transverse momenta $p_T<1$ GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, $x_L>0.35$, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality $Q^2<2$ GeV${}^2$, the total energy of the photon-proton system $20<W_{\gamma p}<100$ GeV and the polar angle of the leading neutron ${\theta }_n<0.75$ mrad. The cross section of the reaction $\gamma p\to {\rho }^{0}n{\pi }^{+}$ is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ${\rho }^0$ meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, ${\sigma }^{\mathrm{el}}(\gamma {\pi }^{+}\to {\rho }^0{\pi }^{+})$, is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction $\gamma p\to {\rho }^{0}n{\pi }^{+}$.

    ↳ hep-exhep-phnucl-exnucl-thEPJC(2016)·25 citations
17. 17*

    The comparison of the 3-fluid dynamic model with experimental data

    V. A. Kizka🇺🇦

    The article considers a way to compare large bulks of experimental data with theoretical calculations, in which the quality of theoretical models is clearly demonstrated graphically. The main idea of the method consists in grouping physical observables, represented by experiment and theoretical calculation, into samples, each of which characterizes a certain physical process. A further choice of a convenient criterion for comparing measurements and calculations, its calculation and averaging within each sample and then over all samples, makes it possible to choose the best theoretical model in the entire measurement area. Published theoretical data of the three-fluid dynamic model (3FD) applied to the experimental data from heavy-ion collisions at the energy range $\sqrt{s_{NN}}=2.7-63$ GeV are used as example of application of the developed methodology. When analyzing the results, the quantum nature of the fireball, created at heavy ion collisions, was taken into account. Thus, even at energy $\sqrt{s_{NN}}=63$ GeV of central collisions of heavy ions, there is a nonzero probability of fireball formation without ignition of the quark-gluon plasma (QGP). At the same time, QGP ignition at central collision energies above at least $\sqrt{s_{NN}}\,=\,12 GeV occurs through two competing processes, through a first-order phase transition and through a smooth crossover. That is, in nature, these two possibilities are realized, which occur with approximately the same probabilities.

    ↳ nucl-thhep-phNuclear Science. Volume 7, Issue 3, Septe…·1 citation
18. 18*

    Melting Hadrons, Boiling Quarks

    Johann Rafelski🇺🇸

    In the context of the Hagedorn temperature half-centenary I describe our understanding of the hot phases of hadronic matter both below and above the Hagedorn temperature. The first part of the review addresses many frequently posed questions about properties of hadronic matter in different phases, phase transition and the exploration of quark-gluon plasma (QGP). The historical context of the discovery of QGP is shown and the role of strangeness and strange antibaryon signature of QGP illustrated. In the second part I discuss the corresponding theoretical ideas and show how experimental results can be used to describe the properties of QGP at hadronization. The material of this review is complemented by two early and unpublished reports containing the prediction of the different forms of hadron matter, and of the formation of QGP in relativistic heavy ion collisions, including the discussion of strangeness, and in particular strange antibaryon signature of QGP.

    ↳ nucl-thhep-exhep-phnucl-ex+1EPJA(2015)·61 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.