HEP Phenomenology·hep-ph

Tue·Dec 5, 2017Tuesday·December 5, 2017

52 papers—35 primary·17 cross-listed·reconstructed*

01*
Determination of the strong coupling constant from inclusive jet cross section data from multiple experiments
Daniel Britzger🇩🇪 · Klaus Rabbertz🇩🇪 · Daniel Savoiu🇩🇪 · Georg Sieber🇩🇪 · Markus Wobisch🇺🇸
Inclusive jet cross section measurements from the ATLAS, CDF, CMS, D0, H1, STAR, and ZEUS experiments are explored for determinations of the strong coupling constant $α_{s} (M_{Z})$ . Various jet cross section data sets are reviewed, their consistency is examined, and the benefit of their simultaneous inclusion in the $α_{s} (M_{Z})$ determination is demonstrated. Different methods for the statistical analysis of these data are compared and one method is proposed for a coherent treatment of all data sets. While the presented studies are based on next-to-leading order in perturbative quantum chromodynamics (pQCD), they lay the groundwork for determinations of $α_{s} (M_{Z})$ at next-to-next-to-leading order.
hep-phEPJC(2019)·36 citations
02*
Meson properties in magnetized quark matter
Ziyue Wang🇨🇳 · Pengfei Zhuang🇨🇳
We study neutral and charged meson properties in magnetic field. Taking bosolization method in a two-flavor Nambu--Jona-Lasinio model, we derive effective meson Lagrangian density with minimal coupling to the magnetic field, by employing derivative expansion for both the meson fields and Schwinger phases. We extract from the effective Lagrangian density the meson curvature, pole and screening masses. As the only Goldstone mode, the neutral pion controls the thermodynamics of the system and propagates the lang range quark interaction. The magnetic field breaks down the space symmetry, and the quark interaction region changes from a sphere in vacuum to a ellipsoid in magnetic field.
hep-phnucl-thPRD(2018)·67 citations
03*
The semileptonic baryonic decay $D_{s}^{+} \to p p ˉ e^{+} ν_{e}$
Hai-Yang Cheng🇹🇼 · Xian-Wei Kang🇹🇼
The decay $D_{s}^{+} \to p p ˉ e^{+} ν_{e}$ with a proton-antiproton pair in the final state is unique in the sense that it is the only semileptonic baryonic decay which is physically allowed in the charmed meson sector. Its measurement will test our basic knowledge on semileptonic $D_{s}^{+}$ decays and the low-energy $p p ˉ$ interactions. Taking into account the major intermediate state contributions from $η, η^{'}, f_{0} (980)$ and $X (1835)$ , we find that its branching fraction is at the level of $1 0^{- 9} \sim 1 0^{- 8}$ . The location and the nature of $X (1835)$ state are crucial for the precise determination of the branching fraction. We wish to trigger a new round of a careful study with the upcoming more data in BESIII as well as the future super tau-charm factory.
hep-phhep-exnucl-thPLB(2018)·14 citations
04*
QCD analysis of leading-neutron production at HERA: Determination of neutron fracture functions
Samira Shoeibi🇮🇷 · F. Taghavi-Shahri🇮🇷 · Kurosh Javidan🇮🇷
The last two decades have seen a growing trend towards the experimental efforts at the electron-proton collider HERA in which have collected high precision data on the spectrum of leading neutron (LN) and leading-proton (LP) carrying a large fraction of the proton's energy. In our recent study [Phys. Rev. D \textbf{95} (2017), 074011], we have proposed an approach based on the Fractures Functions (FF) formalism and have extracted the neutron Fracture Functions (neutron FFs) from a global QCD analysis of LN production data measured by H1 and ZEUS collaborations at HERA. We have shown that considering the approach based on the framework of Fracture Functions, one could phenomenologically parametrize the neutron FFs at the input scale. In order to access the uncertainties for the obtained neutron FFs as well as the LN structure functions and cross section, associated with the uncertainties in the data, we have made an extensive use of the "Hessian method". Our theory predictions based on the obtained neutron FFs are in satisfactory agreement with all LN data analyzed, for a wide range of $β$ and $x_{L}$ .
hep-phhep-exInt.J.Mod.Phys.Conf.Ser.(2018)·0 citations
05*
Model with a gauged lepton flavor SU(2) symmetry
Cheng-Wei Chiang🇹🇼 · Koji Tsumura🇯🇵
We propose a model having a gauged $S U (2)$ symmetry associated with the second and third generations of leptons, dubbed $S U (2)_{μτ}$ , of which $U (1)_{L_{μ} - L_{τ}}$ is an Abelian subgroup. In addition to the Standard Model fields, we introduce two types of scalar fields. One exotic scalar field is an $S U (2)_{μτ}$ doublet and SM singlet that develops a nonzero vacuum expectation value at presumably multi-TeV scale to completely break the $S U (2)_{μτ}$ symmetry, rendering three massive gauge bosons. At the same time, the other exotic scalar field, carrying electroweak as well as $S U (2)_{μτ}$ charges, is induced to have a nonzero vacuum expectation value as well and breaks mass degeneracy between the muon and tau. We examine how the new particles in the model contribute to the muon anomalous magnetic moment in the parameter space compliant with the Michel decays of tau.
hep-phJHEP(2018)·15 citations
06*
Development of heavy-flavour flow-harmonics in high-energy nuclear collisions
Andrea Beraudo🇮🇹 · Arturo De Pace🇮🇹 · Marco Monteno🇮🇹 · Marzia Nardi🇮🇹 · Francesco Prino🇮🇹
We employ the POWLANG transport setup, developed over the last few years, to provide new predictions for several heavy-flavour observables in relativistic heavy-ion collisions from RHIC to LHC center-of-mass energies. In particular, we focus on the development of the flow-harmonics $v_{2}$ and $v_{3}$ arising from the initial geometric asymmetry in the initial conditions and its associated event-by-event fluctuations. Within the same transport framework, for the sake of consistency, we also compare the nuclear modification factor of the $p_{T}$ spectra of charm and beauty quarks, heavy hadrons and their decay electrons. We compare our findings to the most recent data from the experimental collaborations. We also study in detail the contribution to the flow harmonics from the quarks decoupling from the fireball during the various stages of its evolution: although not directly accessible to the experiments, this information can shed light on the major sources of the final measured effect.
hep-phnucl-thJHEP(2018)·41 citations
07*
Nearly perturbative QCD coupling with lattice-motivated zero IR limit
Gorazd Cvetic🇨🇱
The product of the gluon dressing function and the square of the ghost dressing function in the Landau gauge can be regarded to represent, apart from the inverse power corrections $1/ Q^{2 n}$ , a nonperturbative generalization $A (Q^{2})$ of the perturbative QCD running coupling $a (Q^{2})$ ( $\equiv α_{s} (Q^{2}) / π$ ). Recent large volume lattice calculations for these dressing functions strongly indicate that such a generalized coupling goes to zero as $A (Q^{2}) \sim Q^{2}$ when the squared momenta $Q^{2}$ go to zero ( $Q^{2} ≪ 1 GeV^{2}$ ). We construct such a QCD coupling $A (Q^{2})$ which fulfills also various other physically motivated conditions. At high momenta it becomes the underlying perturbative coupling $a (Q^{2})$ to a very high precision. And at intermediately low momenta $Q^{2} \sim 1 GeV^{2}$ it gives results consistent with the data of the semihadronic $τ$ lepton decays as measured by OPAL and ALEPH. The coupling is constructed in a dispersive way, ensuring as a byproduct the holomorphic behavior of $A (Q^{2})$ in the complex $Q^{2}$ -plane which reflects the holomorphic behavior of the spacelike QCD observables. Application of the Borel sum rules to $τ$ -decay V + A spectral functions allows us to obtain values for the gluon (dimension-4) condensate and the dimension-6 condensate, which reproduce the measured OPAL and ALEPH data to a significantly better precision than the perturbative MSbar coupling (+OPE) approach. The comparison with the experimental V-channel Adler function, related with the $e^{+} e^{-} \to$ hadrons ratio, at low $Q^{2} \sim 1 GeV^{2}$ , also gives results considerably better than with the usual MSbar pQCD+OPE approach.
hep-phPoS(2017)·3 citations
08*
Hillclimbing saddle point inflation
Kiyoharu Kawana🇯🇵 · Katsuta Sakai🇯🇵
Recently a new inflationary scenario was proposed in arXiv:1703.09020 which can be applicable to an inflaton having multiple vacua. In this letter, we consider a more general situation where the inflaton potential has a (UV) saddle point around the Planck scale. This class of models can be regarded as a natural generalization of the hillclimbing Higgs inflation (arXiv:1705.03696).
hep-phastro-ph.COgr-qchep-thPLB(2018)·2 citations
09*
Charmed Hadrons from Coalescence plus Fragmentation in relativistic nucleus-nucleus collisions at RHIC and LHC
Salvatore Plumari (1)🇮🇹 · Vincenzo Minissale (1 and 2)🇮🇹 · Santosh K. Das (3 and 1)🇮🇹 · Gabriele Coci (1 and 2)🇮🇹 · Vincenzo Greco (1 and 2) ((1) Department of Physics and Astronomy, University of Catania (2) Laboratori Nazionali del Sud, INFN-LNS (3) School of Nuclear Science and Technology, Lanzhou University, China)🇮🇹
In a coalescence plus fragmentation approach we calculate the heavy baryon/meson ratio and the $p_{T}$ spectra of charmed hadrons $D^{0}$ , $D_{s}$ and $Λ_{c}^{+}$ in a wide range of transverse momentum from low $p_{T}$ up to about 10 GeV and discuss their ratios from RHIC to LHC energies without any change of the coalescence parameters. We have included the contribution from decays of heavy hadron resonances and also the one due to fragmentation of heavy quarks which do not undergo the coalescence process. The coalescence process is tuned to have all charm quarks hadronizing in the $p_{T} \to 0$ limit and at finite $p_{T}$ charm quarks not undergoing coalescence are hadronized by independent fragmentation. The $p_{T}$ dependence of the baryon/meson ratios are found to be sensitive to the masses of coalescing quarks, in particular the $Λ_{c} / D^{0}$ can reach values of about $1 \div 1.5$ at $p_{T} \approx 3$ \mbox{GeV}, or larger, similarly to the light baryon/meson ratio like $p / π$ and $Λ/ K$ , however a marked difference is a quite weak $p_{T}$ dependence with respect to the light case, such that a larger value at intermediate $p_{T}$ implies a relatively large value also for the integrated yields. A comparison with other coalescence model and with the prediction of thermal model is discussed.
hep-phEPJC(2018)·250 citations
10*
The massive 3-loop operator matrix elements with two masses and the generalized variable flavor number scheme
J. Ablinger🇦🇹 · J. Blümlein🇩🇪 · A. De Freitas🇩🇪 · A. Goedicke🇩🇪 · C. Schneider🇦🇹 · K. Schönwald🇩🇪 · F. Wißbrock🇩🇪
We report on our latest results in the calculation of the two--mass contributions to 3--loop operator matrix elements (OMEs). These OMEs are needed to compute the corresponding contributions to the deep-inealstic scattering structure functions and to generalize the variable flavor number scheme by including both charm and bottom quarks. We present the results for the non-singlet and $A_{g q, Q}$ OMEs, and compare the size of their contribution relative to the single mass case. Results for the gluonic OME $A_{g g, Q}$ are given in the physical case, going beyond those presented in a previous publication where scalar diagrams were computed. We also discuss our recently published two--mass contribution to the pure singlet OME, and present an alternative method of calculating the corresponding diagrams.
hep-phhep-exPoS(2017)·1 citation
11*
Can measurements of 2HDM parameters provide hints for high scale supersymmetry?
Gautam Bhattacharyya🇮🇳 · Dipankar Das🇮🇳 · M. Jay Pérez🇪🇸 · Ipsita Saha🇮🇹 · Arcadi Santamaria🇪🇸 · Oscar Vives🇪🇸
Two-Higgs-doublet models (2HDMs) are minimal extensions of the Standard Model (SM) that may still be discovered at the LHC. The quartic couplings of their potentials can be determined from the measurement of the masses and branching ratios of their extended scalar sectors. We show that the evolution of these couplings through renormalization group equations can determine whether the observed 2HDM is a low energy manifestation of a more fundamental theory, as for instance, supersymmetry, which fixes the quartic couplings in terms of the gauge couplings. At leading order, the minimal supersymmetric extension of the SM (MSSM) dictates all the quartic couplings, which can be translated into a predictive structure for the scalar masses and mixings at the weak scale. Running these couplings to higher scales, one can check if they converge to their MSSM values, and more interestingly, whether one can infer the supersymmetry breaking scale. Although we study this question in the context of supersymmetry, this strategy could be applied to any theory whose ultraviolet completion unambiguously predicts all scalar quartic couplings.
hep-phPRD(2018)·6 citations
12*
Explaining the DAMPE $e^{+} e^{-}$ excess using the Higgs triplet model with a vector dark matter
Chuan-Hung Chen🇹🇼 · Cheng-Wei Chiang🇹🇼 · Takaaki Nomura🇰🇷
We explain the $e^{+} e^{-}$ excess observed by the DAMPE Collaboration using a dark matter model based upon the Higgs triplet model and an additional hidden $S U (2)_{X}$ gauge symmetry. Two of the $S U (2)_{X}$ gauge bosons are stable due to a residual discrete symmetry and serve as the dark matter candidate. We search the parameter space for regions that can explain the observed relic abundance, and compute the flux of $e^{+} e^{-}$ coming from a nearby dark matter subhalo. With the inclusion of background cosmic rays, we show that the model can render a good fit to the entire energy spectrum covering the AMS-02, Fermi-LAT and DAMPE data.
hep-phastro-ph.HEPRD(2018)·32 citations
13*
Hadronic Lorentz Violation in Chiral Perturbation Theory Including the Coupling to External Fields
Rasha Kamand🇺🇸 · Brett Altschul🇺🇸 · Matthias R. Schindler🇺🇸
If any violation of Lorentz symmetry exists in the hadron sector, its ultimate origins must lie at the quark level. We continue the analysis of how the theories at these two levels are connected, using chiral perturbation theory. Considering a two-flavor quark theory, with dimension-4 operators that break Lorentz symmetry, we derive a low-energy theory of pions and nucleons that is invariant under local chiral transformations and includes the coupling to external fields. The pure meson and baryon sectors, as well as the couplings between them and the couplings to external electromagnetic and weak gauge fields, contain forms of Lorentz violation which depend on linear combinations of quark-level coefficients. In particular, at leading order the electromagnetic couplings depend on the very same combinations as appear in the free particle propagators. This means that observations of electromagnetic processes involving hadrons--such as vacuum Cerenkov radiation, which may be allowed in Lorentz-violating theories--can only reliably constrain certain particular combinations of quark coefficients.
hep-phhep-thnucl-thPRD(2018)·14 citations
14*
MICROSCOPE limits for new long-range forces and implications for unified theories
Pierre Fayet🇫🇷
Many theories beyond the Standard Model involve an extra U(1) gauge group. The resulting gauge boson U, in general mixed with the Z and the photon, may be massless or very light, and very weakly coupled. It may be viewed as a generalized dark photon interacting with matter through a linear combination (\epsilon_Q Q + \epsilon_B B+\epsilon_L L) e, involving B-L in a grand-unified theory, presumably through B-L-.61 Q, inducing effectively a very small repulsive force between neutrons. This new force, if long-ranged, may manifest through apparent violations of the Equivalence Principle. They are approximately proportional to \epsilon_B+\epsilon_L/2, times a combination involving mostly \epsilon_L. New forces coupled to B-L or L should lead to nearly opposite values of the Eötvös parameter \delta, and to almost the same limits for \epsilon_{B-L} or \epsilon_L, as long as no indication for \delta \neq 0 is found. We derive new limits from the first results of the MICROSCOPE experiment testing the Equivalence Principle in space. A long-range force coupled to (\epsilon_Q Q + \epsilon_{B-L} (B-L)) e or (\epsilon_Q Q + \epsilon_L L) e should verify |\epsilon_{B-L}| or |\epsilon_L| < .8 10^{-24}, and a force coupled to (\epsilon_Q Q + \epsilon_B B) e, |\epsilon_B| < 5 10^{-24}. We also discuss, within supersymmetric theories, how such extremely small gauge couplings g", typically \simle 10^{-24}, may be related to a correspondingly large \xi"D" term associated with a huge initial vacuum energy density, \propto 1/g"^2. The corresponding hierarchy between energy scales, by a factor \propto 1/\sqrt g" \simge 10^{12}, involves a very large scale ~ 10^{16} GeV, that may be associated with inflation, or supersymmetry breaking with a very heavy gravitino, leading to possible values of {\delta} within the experimentally accessible range.
hep-phgr-qchep-exPRD(2018)·73 citations
15*
Scalar dark matter, Type II Seesaw and the DAMPE cosmic ray $e^{+} + e^{-}$ excess
Tong Li🇦🇺 · Nobuchika Okada🇺🇸 · Qaisar Shafi🇺🇸
The DArk Matter Particle Explorer (DAMPE) has reported a measurement of the flux of high energy cosmic ray electrons plus positrons (CREs) in the energy range between $25$ GeV and $4.6$ TeV. With unprecedented high energy resolution, the DAMPE data exhibit an excess of the CREs flux at an energy of around $1.4$ TeV. In this letter, we discuss how the observed excess can be understood in a minimal framework where the Standard Model (SM) is supplemented by a stable SM singlet scalar as dark matter (DM) and type II seesaw for generating the neutrino mass matrix. In our framework, a pair of DM particles annihilates into a pair of the SM SU(2) triplet scalars ( $Δ$ s) in type II seesaw, and the subsequent $Δ$ decays create the primary source of the excessive CREs around $1.4$ TeV. The lepton flavor structure of the primary source of CREs has a direct relationship with the neutrino oscillation data. We find that the DM interpretation of the DAMPE excess determines the pattern of neutrino mass spectrum to be the inverted hierarchy type, taking into account the constraints from the Fermi-LAT observations of dwarf spheroidal galaxies.
hep-phastro-ph.COPLB(2018)·38 citations
16*
Probing compressed mass spectra in electroweak supersymmetry with Recursive Jigsaw Reconstruction
Marco Santoni🇦🇺
The lack of evidence for the production of colored supersymmetric particles at the LHC has increased interest in searches for superpartners of the electroweak SM gauge bosons, namely the neutralinos and charginos. These are challenging due to the weak nature of the production process, and the existing discovery reach has significant gaps in due to the difficulty of separating the supersymmetric signal from SM diboson events that produce similar final states and kinematics. We apply the Recursive Jigsaw Reconstruction technique to study final states enriched in charged leptons and missing transverse momentum, focusing on compressed topologies with direct production of charginos and neutralinos decaying to the lightest neutral supersymmetric particle through the emission of W and Z bosons. After presenting prototype analysis designs for future LHC runs, we demonstrate that its detectors have the potential to probe a significant amount of unexplored parameter space for chargino-neutralino associated production within the next few years, and show that the very challenging successful search for chargino pair production with compressed spectra might be possible by the end of the LHC lifetime.
hep-phJHEP(2018)·2 citations
17*
Quasi-degenerate dark matter for DAMPE excess and $3.5 keV$ line
Pei-Hong Gu🇨🇳
We propose a quasi-degenerate dark matter scenario to simultaneously explain the $1.4 TeV$ peak in the high-energy cosmic-ray electron-positron spectrum reported by the DAMPE collaboration very recently and the $3.5 keV$ X-ray line observed in galaxies clusters and from the Galactic centre and confirmed by the Chandra and NuSTAR satellites. We consider a dark $S U (2)^{'} \times U (1)^{'}$ gauge symmetry under which the dark matter is a Dirac fermion doublet composed of two $S U (2)^{'}$ doublets with non-trivial $U (1)^{'}$ charges. At one-loop level the two dark fermion components can have a mass split as a result of the dark gauge symmetry breaking. Through the exchange of a mediator scalar doublet the two quasi-degenerate dark fermions can mostly annihilate into the electron-positron pairs at tree level for explaining the $1.4 TeV$ positron anomaly, meanwhile, the heavy dark fermion can very slowly decay into the light dark fermion with a photon at one-loop level for explaining the $3.5 keV$ X-ray line. Our dark fermions can be also verified in the direct detection experiments.
hep-phSCPMA(2018)·18 citations
18*
Radiative seesaw models linking to dark matter candidates inspired by the DAMPE excess
Takaaki Nomura🇰🇷 · Hiroshi Okada🇹🇼
We propose two possibilities to explain an excess of electron/positron flux around 1.4 TeV recently reported by Dark Matter Explore (DAMPE) in the framework of radiative seesaw models where one of them provides a fermionic dark matter candidate, and the other one provides a bosonic dark matter candidate. We also show unique features of both models regarding neutrino mass structure.
hep-phPhys.Dark Univ.(2018)·29 citations
19*
Two-loop mass splittings in electroweak multiplets: winos and minimal dark matter
James McKay🇬🇧 · Pat Scott🇬🇧
The radiatively-induced splitting of masses in electroweak multiplets is relevant for both collider phenomenology and dark matter. Precision two-loop corrections of $O$ (MeV) to the triplet mass splitting in the wino limit of the minimal supersymmetric standard model can affect particle lifetimes by up to $40%$ . We improve on previous two-loop self-energy calculations for the wino model by obtaining consistent input parameters to the calculation via two-loop renormalisation-group running, and including the effect of finite light quark masses. We also present the first two-loop calculation of the mass splitting in an electroweak fermionic quintuplet, corresponding to the viable form of minimal dark matter (MDM). We place significant constraints on the lifetimes of the charged and doubly-charged fermions in this model. We find that the two-loop mass splittings in the MDM quintuplet are not constant in the large-mass limit, as might naively be expected from the triplet calculation. This is due to the influence of the additional heavy fermions in loop corrections to the gauge boson propagators.
hep-phPRD(2018)·29 citations
20*
Line-shape and poles of the $ψ (3770)$
Susana Coito🇵🇱 · Francesco Giacosa🇩🇪
We study the non-Breit-Wigner line-shape of the $ψ (3770)$ resonance, predominantly a $1^{3} D_{1}$ $c ˉ c$ state, using an unitarized effective Lagrangian approach, including the one-loop effects of the nearby thresholds $D^{+} D^{-}$ and $D^{0} D ˉ^{0}$ . A fit of the theoretical result to the total cross-section $e^{+} e^{-} \to D D ˉ$ is performed, leading to a good description of data ( $χ^{2} / d . o . f . \sim 1.03$ ). The partial cross sections $e^{+} e^{-} \to D^{0} D ˉ^{0}$ and $e^{+} e^{-} \to D^{+} D^{-}$ turn out to be separately in good agreement with the experiment. We find a pole at $3777 - i 12$ MeV, that is within the Particle Data Group (PDG) mass and width estimation for this state. Quite remarkably, we find an additional, dynamically generated, companion pole at $3741 - i 19$ MeV, which is responsible for the deformation on the lower energy side of the line-shape. The width for the leptonic decay $ψ (3770) \to e^{+} e^{-}$ is 112 eV, hence smaller than the PDG fit of $262 \pm 18$ eV, yet in agreement with a recent experimental study.
hep-phNPA(2019)·24 citations
21*
Exotic candidates with heavy quark(s)
Qian Wang🇩🇪
In the last decades, the number of exotic candidates which are beyond the conventional quark model has grown dramatically. At the same time, numerous theoretical interpretations, such as tetraquark, hybrid, hadroquarkonium and hadronic molecule, have been proposed to understand their nature. In principle, all the configurations with the same quantum numbers can mix with each other. Thus at present we aim at identifying the prominent component. As an extended object, a hadronic molecule has some distinguishable features from other more compact configurations. In the end, the two $Z_{b}$ states are used to illustrate some features of the molecular scenario.
hep-phPoS(2018)·0 citations
22*
The coherent weak charge of matter
Alejandro Segarra🇪🇸
We study the long-range force arising between two aggregates of ordinary matter due to a neutrino-pair exchange, in the limit of zero neutrino mass. Even if matter is neutral of electric charge, it is charged for this weak force. The interaction is described in terms of a coherent charge, which we call the weak flavor charge of aggregated matter. For each one of the interacting aggregates, this charge depends on the neutrino flavor as $Q_{W}^{ν_{e}} = 2 Z - N$ , $Q_{W}^{ν_{μ}} = Q_{W}^{ν_{τ}} = - N$ , where $Z$ is the number of protons and $N$ the number of neutrons. $Q_{W}^{ν_{e}}$ depends explicitly on $Z$ because of the charged current contribution to $ν_{e} e$ elastic scattering, while the $N$ term in the three charges comes from the universal neutral current contribution. The effective potential describing this force is repulsive and decreases as $r^{- 5}$ . Due to its specific behavior on $(Z, N)$ and $r$ , this interaction is distinguishable from both gravitation and residual electromagnetic forces. As neutrinos are massive and mixed, this potential is valid for $r ≲ 1/ m_{ν}$ , distances beyond which a Yukawa-like attenuation kicks in.
hep-ph3 citations
23*
Excited vector mesons: phenomenology and predictions for a yet unknown vector $s s ˉ$ state with a mass of about 1.93 GeV
Milena Piotrowska🇵🇱 · Francesco Giacosa🇩🇪
The firm understanding of standard quark-antiquark states (including excited states) is necessary to search for non-conventional mesons with the same quantum numbers. In this work, we study the phenomenology of two nonets of excited vector mesons, which predominantly correspond to radially excited vector mesons with quantum numbers $n$ $^{2 S + 1} L_{J} = 2$ $^{3} S_{1}$ and to orbitally excited vector mesons with quantum numbers $n$ ~ $^{2 S + 1} L_{J} = 1$ $^{3} D_{1}$ . We evaluate the decays of these mesons into two pseudoscalar mesons and into a pseudoscalar and a ground-state vector meson by making use of a relativistic quantum field theoretical model based on flavor symmetry. Moreover, we also study the radiative decays into a photon and a pseudoscalar meson by using vector meson dominance. We compare our results to the PDG and comment on open issues concerning the corresponding measured resonances. Within our approach, we are also able to make predictions for a not-yet discovered $s s ˉ$ state in the $n$ $^{2 S + 1} L_{J} = 1$ $^{3} D_{1}$ nonet, which has a mass of about 1.93 GeV. This resonance can be searched in the upcoming GlueX and CLAS12 experiments which take place at the Jefferson Lab.
hep-phEPJ Web Conf.(2018)·2 citations
24*
Theory Concepts for Heavy Exotic Mesons
C. Hanhart🇩🇪
Some of the currently most popular conjectures for the structure of the recently discovered heavy mesons that do not find a place in the quark model quarkonium spectrum are sketched. Furthermore, some observables are identified that should allow one to identify the most prominent components of individual states.
hep-phhep-exInt.J.Mod.Phys.Conf.Ser.(2018)·4 citations
25*
Graviton-mediated dark matter model explanation the DAMPE electron excess and search at $e^{+} e^{-}$ colliders
Ruilin Zhu🇨🇳 · Yu Zhang🇨🇳
The very recent result of the DAMPE cosmic ray spectrum of electrons shows a narrow bump above the background at around 1.4 TeV. We attempt to explain the DAMPE electron excess in a simplified Kaluza-Klein graviton-mediated dark matter model, in which the graviton only interacts with leptons and dark matter. The related phenomenological discussions are given and this simplified graviton-mediated dark matter model has the potential to be cross-tested in future lepton collider experiments.
hep-phastro-ph.HEhep-ex19 citations
26*
Higher-order corrections for $tZ$ production via anomalous couplings
Nikolaos Kidonakis🇺🇸
I present higher-order corrections from soft-gluon emission for the associated production of a top quark with a $Z$ boson via anomalous $t$ - $q$ - $Z$ couplings at LHC energies. Approximate next-to-next-to-leading order (aNNLO) double-differential cross sections are derived from soft-gluon resummation at next-to-leading-logarithm accuracy. The total $tZ$ production cross sections and the top-quark transverse-momentum and rapidity distributions are calculated at aNNLO for various LHC energies. It is shown that the soft-gluon corrections are dominant and large for this process.
hep-phPRD(2018)·24 citations
27*
Energy loss during Dark Matter propagation in an overburden
M. Shafi Mahdawi🇺🇸 · Glennys R. Farrar🇺🇸
As experimental constraints on DM interactions become ever more sensitive and push into new regimes of DM mass, it becomes more and more challenging to accurately model the process by which Dark Matter particles lose energy through scattering in the Earth's surface or other overburdens. We show that a commonly-used approximation due to Starkman, Gould, Esmailzadeh and Dimopoulos (SGED) can fail badly in computing the attenuation, even while being useful for an order-of-magnitude estimate of the maximum cross section reach. We introduce a method of importance sampling which makes Monte-Carlo simulation of energy loss feasible, in spite of factor- $1 0^{7}$ or greater attenuation. We demonstrate the validity of our new method and expose multiple problems with the SGED approximation, this reveals interesting features of the energy loss process. We spot-check the recent Emken, Kouvaris and Shoemaker " $5 Δ v$ " prescription to place limits on cross sections based on a limited-statistics analysis, and find that an accurate simulation yields a factor of $4.4 \times 1 0^{6}$ and $2.4 \times 1 0^{4}$ larger number of events, for 50 MeV and 1 GeV DM mass respectively, than if the EKS $5 Δ v$ prescription were valid.
hep-phastro-ph.HE25 citations
28*
Charm Penguin in $B^{\pm} \to K^{\pm} K^{+} K^{-}$ : partonic and hadronic loops
Ignacio Bediaga🇧🇷 · Tobias Frederico🇧🇷 · Patricia C Magalhães🇧🇷
Charm penguin diagrams are known to be the main contribution to charmless B decay process with strangeness variation equal to minus one, which is the case of $B^{\pm} \to K^{\pm} K^{+} K^{-}$ decay. The large phase space available in this and other B three-body decays allows non trivial final state interactions with all sort of rescattering processes and also access high momentum transfers in the central region of the Dalitz plane. In this work we investigate the charm Penguin contribution to $B^{\pm} \to K^{\pm} K^{+} K^{-}$ , described by a hadronic triangle loop in nonperturbative regions of the phase space, and by a partonic loop at the quasi perturbative region. These nonresonant amplitudes should have a particular structure in the Dalitz plane and their contributions to the final decay amplitude can be confirmed by a data amplitude analysis in this channel. In particular, the hadronic amplitude has a changing sign in the phase at $D D ˉ$ threshold which can result in a change of sign for the CP asymmetry.
hep-phhep-exPLB(2018)·18 citations
29*
DAMPE Electron-Positron Excess in Leptophilic $Z^{'}$ model
Karim Ghorbani🇮🇷 · Parsa Hossein Ghorbani🇮🇷
Recently the DArk Matter Particle Explorer (DAMPE) has reported an excess in the electron-positron flux of the cosmic rays which is interpreted as a dark matter particle with the mass about $1.5$ TeV. We come up with a leptophilic $Z^{'}$ scenario including a Dirac fermion dark matter candidate which beside explaining the observed DAMPE excess, is able to pass various experimental/observational constraints including the relic density value from the WMAP/Planck, the invisible Higgs decay bound at the LHC, the LEP bounds in electron-positron scattering, the muon anomalous magnetic moment constraint, Fermi-LAT data, and finally the direct detection experiment limits from the XENON1t/LUX. By computing the electron-positron flux produced from a dark matter with the mass about $1.5$ TeV we show that the model predicts the peak observed by the DAMPE.
hep-phJHEP(2018)·30 citations
30*
Explaining the DAMPE data with scalar dark matter and gauged $U (1)_{L_{e} - L_{μ}}$ interaction
Junjie Cao🇨🇳 · Lei Feng🇨🇳 · Xiaofei Guo🇨🇳 · Liangliang Shang🇨🇳 · Fei Wang🇨🇳 · Peiwen Wu🇰🇷 · Lei Zu🇨🇳
Inspired by the peak structure observed by recent DAMPE experiment in $e^{+} e^{-}$ cosmic-ray spectrum, we consider a scalar dark matter (DM) model with gauged $U (1)_{L_{e} - L_{μ}}$ symmetry, which is the most economical anomaly-free theory to potentially explain the peak by DM annihilation in nearby subhalo. We utilize the process $χχ \to Z^{'} Z^{'} \to l l ˉ l^{'} l ˉ^{'}$ , where $χ$ , $Z^{'}$ , $l^{(')}$ denote the scalar DM, the new gauge boson and $l^{(')} = e, μ$ , respectively, to generate the $e^{+} e^{-}$ spectrum. By fitting the predicted spectrum to the experimental data, we obtain the favored DM mass range $m_{χ} ≃ 306 0_{- 100}^{+ 80} GeV$ and $Δ m \equiv m_{χ} - m_{Z^{'}} ≲ 14 GeV$ at $68%$ Confidence Level (C.L.). Furthermore, we determine the parameter space of the model which can explain the peak and meanwhile satisfy the constraints from DM relic abundance, DM direct detection and the collider bounds. We conclude that the model we consider can account for the peak, although there exists a tension with the constraints from the LEP-II bound on $m_{Z^{'}}$ arising from the cross section measurement of $e^{+} e^{-} \to Z^{' *} \to e^{+} e^{-}$ .
hep-phEPJC(2018)·33 citations
31*
IR properties of chiral effects in pionic matter
A. Avdoshkin🇷🇺 · A. V. Sadofyev🇺🇸 · V. I. Zakharov🇷🇺
Chiral effects exhibit peculiar universality in idealized theoretical limits. However, they are known to be infrared sensitive and get modified in more realistic settings. In this work, we study how the corresponding conductivities vary with the constituent mass. We concentrate on a pionic realization of chiral effects which provides a better control over infrared properties of the theory. The pionic medium is considered at finite vector and axial isospin chemical potentials in the presence of an external magnetic field. This system supports electric and axial isospin currents along the magnetic field which correspond to chiral magnetic and chiral separation effects. We show that these currents are sensitive to the finite mass of the constituents, but the conductivities follow a simple scaling with the corresponding charge densities as one would expect for polarization effects. It is argued that this relation can capture the dependence of chiral effects on other infrared parameters. Finally, we briefly comment on the realization of the 't Hooft matching condition in pionic media at finite densities.
hep-phnucl-thPRD(2018)·12 citations
32*
$S O (10)$ inspired $Z^{'}$ models at the LHC
Simon J.D. King🇬🇧 · Stephen F. King🇬🇧 · Stefano Moretti🇬🇧
We study and compare various $Z^{'}$ models arising from $S O (10)$ , focussing in particular on the Abelian subgroup $U (1)_{R} \times U (1)_{B - L}$ , broken at the TeV scale to Standard Model hypercharge $U (1)_{Y}$ . The gauge group $U (1)_{R} \times U (1)_{B - L}$ , which is equivalent to the $U (1)_{Y} \times U (1)_{χ}$ in a different basis, is well motivated from $S O (10)$ breaking and allows neutrino mass via the linear seesaw mechanism. Assuming supersymmetry, we consider single step gauge unification to predict the gauge couplings, then consider the detection and characterisation prospects of the resulting $Z^{'}$ at the LHC by studying its possible decay modes into di-leptons as well as into Higgs bosons. The main new result here is to analyse in detail the expected leptonic forward-backward asymmetry at the high luminosity LHC and show that it may be used to discriminate the $U (1)_{R} \times U (1)_{B - L}$ model from the usual $B - L$ model based on $U (1)_{Y} \times U (1)_{B - L}$ .
hep-phPRD(2018)·10 citations
33*
Leptoquarks meet $ε^{'} / ε$ and rare Kaon processes
Christoph Bobeth🇩🇪 · Andrzej J. Buras🇩🇪
We analyse for the first time the CP violating ratio $ε^{'} / ε$ in $K \to π π$ decays in leptoquark (LQ) models. Assuming a mass gap to the electroweak (EW) scale, the main mechanism for LQs to contribute to $ε^{'} / ε$ is EW gauge-mixing of semi-leptonic into non-leptonic operators, which we treat in the Standard Model effective theory (SMEFT). We perform also the one-loop decoupling for scalar LQs, finding that in all models with both left-handed and right-handed LQ couplings box-diagrams generate numerically strongly enhanced EW-penguin operators $Q_{8, 8^{'}}$ already at the LQ scale. We then investigate correlations of $ε^{'} / ε$ with rare Kaon processes ( $K_{L} \to π^{0} ν ν ˉ$ , $K^{+} \to π^{+} ν ν ˉ$ , $K_{L} \to π^{0} ℓ ℓ ˉ$ , $K_{S} \to μ μ ˉ$ , $Δ M_{K}$ and $ε_{K}$ ) and find that even imposing only a moderate enhancement of $(ε^{'} / ε)_{NP} = 5 \times 1 0^{- 4}$ to explain the current anomaly hinted by the Dual QCD approach and RBC-UKQCD lattice QCD calculations leads to conflicts with experimental upper bounds on rare Kaon processes. They exclude all LQ models with only a single coupling as an explanation of the $ε^{'} / ε$ anomaly and put strong-to-serious constraints on parameter spaces of the remaining models. Future results on $K^{+} \to π^{+} ν ν ˉ$ from the NA62 collaboration, $K_{L} \to π^{0} ν ν ˉ$ from the KOTO experiment and $K_{S} \to μ μ ˉ$ from LHCb will even stronger exhibit the difficulty of LQ models in explaining the measured $ε^{'} / ε$ , in case the $ε^{'} / ε$ anomaly will be confirmed by improved lattice QCD calculations. Hopefully also improved measurements of $K_{L} \to π^{0} ℓ ℓ ˉ$ decays will one day help in this context.
hep-phhep-exhep-latJHEP(2018)·129 citations
34*
Using time-dependent indirect $C P$ asymmetries to measure $T$ and $C P T$ violation in $B^{0}$ - $B ˉ^{0}$ mixing
Anirban Karan🇮🇳 · Abinash Kumar Nayak🇮🇳 · Rahul Sinha🇮🇳 · David London🇨🇦
Quantum field theory, which is the basis for all of particle physics, requires that all processes respect $C P T$ invariance. It is therefore of paramount importance to test the validity of $C P T$ conservation. In this Letter, we show that the time-dependent, indirect $C P$ asymmetries involving $B$ decays to a $C P$ eigenstate contain enough information to measure $T$ and $C P T$ violation in $B^{0}$ - $B ˉ^{0}$ mixing, in addition to the standard $C P$ -violating weak phases. Entangled $B^{0} B ˉ^{0}$ states are not required (so that this analysis can be carried out at LHCb, as well as at the $B$ factories), penguin pollution need not be neglected, and the measurements can be made even if the $B^{0}$ - $B ˉ^{0}$ width difference vanishes.
hep-phPLB(2018)·8 citations
35*
Future prospects of mass-degenerate Higgs bosons in the $C P$ -conserving two-Higgs-doublet model
Ligong Bian🇨🇳 · Ning Chen🇨🇳 · Wei Su🇨🇳 · Yongcheng Wu🇨🇦 · Yu Zhang🇨🇳
The scenario of two mass-degenerate Higgs bosons within the general two-Higgs-doublet model (2HDM) is revisited. We focus on the global picture when two $C P$ -even Higgs bosons of $h$ and $H$ are nearly mass-degenerate. A global fit to the signal strength of the 125 GeV Higgs measured at the LHC is performed. Based on the best-fit result of the 2HDM mixing angles $(α, β)$ , theoretical constraints, charged and $C P$ -odd Higgs boson direct search constraints and the electroweak precision constraints are imposed to the 2HDM parameter space. We present the signal predictions of the $(4 b, 2 b 2 γ)$ channels for the benchmark models at the LHC 14 TeV runs. We also study the direct Higgs boson pair productions at the LHC, and the Z-associated Higgs boson pair production search at the ILC 500 GeV runs, as well as the indirect probes at the CEPC 250 GeV run. We find that the mass-degenerate Higgs boson scenario in the Type-II 2HDM can be fully probed by these future experimental searches.
hep-phhep-exPRD(2018)·12 citations
36*
Status of Dark Matter Searches (Rapporteur Talk)
Carsten Rott🇰🇷
This article reviews the status of the field of dark matter as of summer 2017, when it was discussed at 35th International Cosmic Ray Conference (ICRC 2017) in Busan, Korea. It is the write-up of a rapporteur talk on the status of dark matter searches given at the conference.
↳ astro-ph.HEhep-phPoS(2018)·12 citations
37*
Searching for the Subatomic Swirls in the CuCu and CuAu Collisions
Shuzhe Shi🇺🇸 · Kangle Li🇨🇳 · Jinfeng Liao🇺🇸
Recently the STAR Collaboration discovered the "subatomic swirls", that is, the most vortical fluid flow structures in the quark-gluon plasma produced via the AuAu collisions at the Relativistic Heavy Ion Collider (RHIC). Published in Nature and featured as a cover story, this discovery attracted significant interest and generated wide enthusiasm. For such an important finding, it is crucial to look for independent evidences of confirmation and to critically test the current interpretation of the global polarization measurement. We suggest that the CuCu and CuAu colliding systems at RHIC provide such opportunity. Interestingly, our calculations reveal that the fluid vorticity in the CuCu or CuAu collision is comparable to that in the AuAu Collision. Surprisingly, we find the computed $Λ$ hyperon polarization effect is stronger in the CuCu and CuAu systems than the AuAu system at the same collisional beam energy and centrality class, with an interesting hierarchy CuCu $>$ CuAu $>$ AuAu due to interplay between $Λ$ production timing and the time evolution of the vorticity. These predictions can be readily tested by experimental data.
↳ nucl-thhep-phPLB(2019)·90 citations
38*
Temperature dependence of transport coefficients of QCD in high-energy heavy-ion collisions
Kazuhisa Okamoto🇯🇵 · Chiho Nonaka🇯🇵
Using our developed new relativistic viscous hydrodynamics code, we investigate the temperature dependence of shear and bulk viscosities from comparison with the ALICE data: single particle spectra and collective flows of Pb+Pb $s_{NN} = 2.76$ TeV collisions at the Large Hadron Collider. We find that from the comprehensive analyses of centrality dependence of single particle spectra and collective flows we can extract detailed information on the quark-gluon plasma bulk property, without the information being smeared by the final state interactions.
↳ nucl-thhep-phnucl-exPRC(2018)·16 citations
39*
Secular Terms in Dyson Series to All-Orders of Perturbation
Satoshi Iso🇯🇵 · Hikaru Ohta🇯🇵 · Takao Suyama🇯🇵
In classical and quantum systems, perturbation of an evolution equation is often invalidated by secular terms which diverge at late times. The diverging behavior of evolution can be remedied by various techniques of resumma- tion such as renormalization group or multi-scale analysis. In this paper, we prove that, in a generic quantum mechanical system, secular terms can be systematically removed to all orders in the Dyson series by the method of improved (renormalized) perturbation. A recurrence relation to provide an explicit method to remove the secular terms is given. As a byproduct, we give a simple method to obtain energy eigenvalues and decay rates to all orders of perturbation.
↳ hep-thhep-phmath-phmath.MP+1PTEP(2018)·3 citations
40*
MADMAX: A new way of probing QCD Axion Dark Matter with a Dielectric Haloscope -- Foundations
Stefan Knirck (for the MADMAX interest group)🇩🇪
In contrast to WIMPs, light Dark Matter candidates have increasingly come under the focus of scientific interest. In particular the QCD axion is also able to solve other fundamental problems such as CP-conservation in strong interactions. Galactic axions, axion-like particles and hidden photons can be converted to photons at boundaries between materials of different dielectric constants under a strong magnetic field. Combining many such surfaces, one can enhance this conversion significantly using constructive interference and resonances. The proposed MADMAX setup containing 80 high dielectric disks in a \SI{10}{\tesla} magnetic field would probe the well-motivated mass range of $40$ --\SI{400}{\micro\electronvolt}, a range which is at present inaccessible by existing cavity searches. We present the foundations of this approach and its expected sensitivity.
↳ physics.ins-dethep-phJ.Phys.Conf.Ser.(2020)·1 citation
41*
Minimum Interior Temperature for Solid Objects Implied by Collapse Models
Stephen L. Adler🇺🇸
Heating induced by the noise postulated in wave function collapse models leads to a lower bound to the temperature of solid objects. For the noise parameter values $λ = coupling strength \sim 1 0^{- 8} s^{- 1}$ and $r_{C} = correlation length \sim 1 0^{- 5} cm$ , which were suggested \cite{adler1} to make latent image formation an indicator of wave function collapse and which are consistent with the recent experiment of Vinante et al. \cite{vin}, the effect may be observable. For metals, where the heat conductivity is proportional to the temperature at low temperatures, the lower bound (specifically for RRR=30 copper) is $\sim 5 \times 1 0^{- 11} (L / r_{C})$ K, with L the size of the object. For the thermal insulator Torlon 4203, the comparable lower bound is $\sim 3 \times 1 0^{- 6} (L / r_{c})^{0.63}$ K. We first give a rough estimate for a cubical metal solid, and then give an exact solution of the heat transfer problem for a sphere.
↳ quant-phcond-mat.otherhep-phhep-th1 citation
42*
Path optimization method for the sign problem
Akira Ohnishi🇯🇵 · Yuto Mori🇯🇵 · Kouji Kashiwa🇯🇵
We propose a path optimization method (POM) to evade the sign problem in the Monte-Carlo calculations for complex actions. Among many approaches to the sign problem, the Lefschetz-thimble path-integral method and the complex Langevin method are promising and extensively discussed. In these methods, real field variables are complexified and the integration manifold is determined by the flow equations or stochastically sampled. When we have singular points of the action or multiple critical points near the original integral surface, however, we have a risk to encounter the residual and global sign problems or the singular drift term problem. One of the ways to avoid the singular points is to optimize the integration path which is designed not to hit the singular points of the Boltzmann weight. By specifying the one-dimensional integration-path as $z = t + i f (t) (f \in R)$ and by optimizing $f (t)$ to enhance the average phase factor, we demonstrate that we can avoid the sign problem in a one-variable toy model for which the complex Langevin method is found to fail. In this proceedings, we propose POM and discuss how we can avoid the sign problem in a toy model. We also discuss the possibility to utilize the neural network to optimize the path.
↳ hep-lathep-phnucl-thEPJ Web Conf.(2018)·10 citations
43*
Gravitational clustering of cosmic relic neutrinos in the Milky Way
Jue Zhang🇨🇳 · Xin Zhang🇨🇳
The standard model of cosmology predicts the existence of cosmic neutrino background in the present Universe. To detect cosmic relic neutrinos in the vicinity of the Earth, it is necessary to evaluate the gravitational clustering effects on relic neutrinos in the Milky Way. Here we introduce a reweighting technique in the N-one-body simulation method, so that a single simulation can yield neutrino density profiles for different neutrino masses and phase space distributions. In light of current experimental results that favor small neutrino masses, the neutrino number density contrast around the Earth is found to be almost proportional to the square of neutrino mass. The density contrast-mass relation and the reweighting technique are useful for studying the phenomenology associated with the future detection of the cosmic neutrino background.
↳ astro-ph.COhep-phNature Commun.(2018)·55 citations
44*
Does the gravitomagnetic monopole exist? A clue from a black hole x-ray binary
Chandrachur Chakraborty (KIAA, China)🇨🇳 · Sudip Bhattacharyya (TIFR, India)🇮🇳
The gravitomagnetic monopole is the proposed gravitational analogue of Dirac's magnetic monopole. However, an observational evidence of this aspect of fundamental physics was elusive. Here, we employ a technique involving three primary X-ray observational methods used to measure a black hole spin to search for the gravitomagnetic monopole. These independent methods give significantly different spin values for an accreting black hole. We demonstrate that the inclusion of one extra parameter due to the gravitomagnetic monopole not only makes the spin and other parameter values inferred from the three methods consistent with each other but also makes the inferred black hole mass consistent with an independently measured value. We argue that this first indication of the gravitomagnetic monopole, within our paradigm, is not a result of fine tuning.
↳ astro-ph.HEgr-qchep-phhep-thPRD(2018)·57 citations
45*
Large directed flow of open charm mesons probes the three dimensional distribution of matter in heavy ion collisions
Sandeep Chatterjee🇵🇱 · Piotr Bożek🇵🇱
Thermalized matter created in non-central relativistic heavy-ion collisions is expected to be tilted in the reaction plane with respect to the beam axis. The most notable consequence of this forward-backward symmetry breaking is the observation of rapidity-odd directed flow for charged particles. On the other hand, the production points for heavy quarks are forward-backward symmetric and shifted in the transverse plane with respect to the fireball. The drag of heavy quarks from the asymmetrically distributed thermalized matter generates a large directed flow for heavy flavor mesons. We predict a very large rapidity odd directed flow of $D$ mesons in non-central Au-Au collisions at $s_{N N} = 200$ GeV, $se v er a l$ $t im es$ $l a r g er$ than for charged particles. A possible experimental observation of a large directed flow for heavy flavor mesons would represent an almost direct probe of the 3-dimensional distribution of matter in heavy-ion collisions.
↳ nucl-thhep-exhep-phnucl-exPRL(2018)·89 citations
46*
Reannihilation of self-interacting dark matter
Tobias Binder🇩🇪 · Michael Gustafsson🇩🇪 · Ayuki Kamada🇰🇷 · Stefan Marinus Rodrigues Sandner🇩🇪 · Max Wiesner🇩🇪
We explore the phenomenology of having a second epoch of dark matter annihilation into dark radiation long after the standard thermal freeze-out. Such a hidden reannihilation process could affect visible sectors only gravitationally. As a concrete realization we consider self-interacting dark matter (SIDM) with a light force mediator coupled to dark radiation. We demonstrate how resonantly Sommerfeld enhanced cross sections emerge to induce the reannihilation epoch. The effect is a temporally local modification of the Hubble expansion rate and we show that the Cosmic Microwave Background (CMB) measurements -- as well as other observations -- have a high sensitivity to observe this phenomenon. Special attention is given to the model region where late kinetic decoupling and strong self-interactions can alleviate several small-scale problems in the cold dark matter paradigm at the same time. Interestingly, we find that reannihilation might here also simultaneously lower the tension between CMB and low-redshift astronomical observations of $H_{0}$ and $σ_{8}$ . Moreover, we identify reannihilation as a clear signature to discriminate between the phenomenologically otherwise almost identical vector and scalar mediator realizations of SIDM.
↳ astro-ph.COhep-phPRD(2018)·56 citations
47*
Bounds on Neutrino Mass in Viscous Cosmology
Sampurn Anand🇮🇳 · Prakrut Chaubal🇮🇳 · Arindam Mazumdar🇮🇳 · Subhendra Mohanty🇮🇳 · Priyank Parashari🇮🇳
Effective field theory of dark matter fluid on large scales predicts the presence of viscosity of the order of $1 0^{- 6} H_{0} M_{P}^{2}$ . It has been shown that this magnitude of viscosities can resolve the discordance between large scale structure observations and Planck CMB data in the $σ_{8}$ - $Ω_{m}^{0}$ and $H_{0}$ - $Ω_{m}^{0}$ parameters space. Massive neutrinos suppresses the matter power spectrum on the small length scales similar to the viscosities. We show that by including the effective viscosity, which arises from summing over non linear perturbations at small length scales, severely constrains the cosmological bound on neutrino masses. Under a joint analysis of Planck CMB and different large scale observation data, we find that upper bound on the sum of the neutrino masses at 2- $σ$ level, decreases from $\sum m_{ν} \leq 0.396$ eV (normal hierarchy) and $\sum m_{ν} \leq 0.378$ eV (inverted hierarchy) to $\sum m_{ν} \leq 0.267$ eV (normal hierarchy) and $\sum m_{ν} \leq 0.146$ eV (inverted hierarchy) when the effective viscosities are included.
↳ astro-ph.COhep-phJCAP(2018)·16 citations
48*
Consistent hydrodynamic theory of chiral electrons in Weyl semimetals
E. V. Gorbar🇺🇦 · V. A. Miransky🇨🇦 · I. A. Shovkovy🇺🇸 · P. O. Sukhachov🇨🇦
The complete set of Maxwell's and hydrodynamic equations for the chiral electrons in Weyl semimetals is presented. The formulation of the Euler equation takes into account the explicit breaking of the Galilean invariance by the ion lattice. It is shown that the Chern-Simons (or Bardeen-Zumino) contributions should be added to the electric current and charge densities in Maxwell's equations that provide the information on the separation of Weyl nodes in energy and momentum. On the other hand, these topological contributions do not directly affect the Euler equation and the energy conservation relation for the electron fluid. By making use of the proposed consistent hydrodynamic framework, we show that the Chern-Simons contributions strongly modify the dispersion relations of collective modes in Weyl semimetals. This is reflected, in particular, in the existence of distinctive anomalous Hall waves, which are sustained by the local anomalous Hall currents.
↳ cond-mat.str-elhep-phnucl-thPRB(2018)·30 citations
49*
Baryon Chiral Perturbation Theory combined with the $1/ N_{c}$ Expansion in SU(3) I: Framework
Ishara P. Fernando🇺🇸 · Jose L. Goity🇺🇸
Baryon Chiral Perturbation Theory combined with the $1/ N_{c}$ expansion is implemented for three flavors. Baryon masses, vector charges and axial vector couplings are studied to one-loop and organized according to the $ξ$ -expansion, in which the $1/ N_{c}$ and the low energy power countings are linked according to $1/ N_{c} = O (ξ) = O (p)$ . The renormalization to $O (ξ^{3})$ necessary for the mentioned observables is provided, along with applications to the baryon masses and axial couplings as obtained in lattice QCD calculations.
↳ nucl-thhep-phPRD(2018)·10 citations
50*
Cosmological model-independent test of $Λ$ CDM with two-point diagnostic by the observational Hubble parameter data
Shu-Lei Cao🇨🇳 · Xiao-Wei Duan🇨🇳 · Xiao-Lei Meng🇨🇳 · Tong-Jie Zhang🇨🇳
Aiming at exploring the nature of dark energy (DE), we use forty-three observational Hubble parameter data (OHD) in the redshift range $0 < z ⩽ 2.36$ to make a cosmological model-independent test of the $Λ$ CDM model with two-point $O m h^{2} (z_{2}; z_{1})$ diagnostic. In $Λ$ CDM model, with equation of state (EoS) $w = - 1$ , two-point diagnostic relation $O m h^{2} \equiv Ω_{m} h^{2}$ is tenable, where $Ω_{m}$ is the present matter density parameter, and $h$ is the Hubble parameter divided by 100 $km s^{- 1} Mp c^{- 1}$ . We utilize two methods: the weighted mean and median statistics to bin the OHD to increase the signal-to-noise ratio of the measurements. The binning methods turn out to be promising and considered to be robust. By applying the two-point diagnostic to the binned data, we find that although the best-fit values of $O m h^{2}$ fluctuate as the continuous redshift intervals change, on average, they are continuous with being constant within 1 $σ$ confidence interval. Therefore, we conclude that the $Λ$ CDM model cannot be ruled out.
↳ astro-ph.COhep-phhep-thEPJC(2018)·36 citations
51*
Relativistic Dynamics of Point Magnetic Moment
Johann Rafelski🇺🇸 · Martin Formanek🇺🇸 · Andrew Steinmetz🇺🇸
The covariant motion of a classical point particle with magnetic moment in the presence of (external) electromagnetic fields is revisited. We are interested in understanding Lorentz force extension involving point particle magnetic moment (Stern-Gerlach force) and how the spin precession dynamics is modified for consistency. We introduce spin as a classical particle property inherent to Poincareé symmetry of space-time. We propose a covariant formulation of the magnetic force based on a \lq magnetic\rq\ 4-potential and show how the point particle magnetic moment relates to the Amperian (current loop) and Gilbertian (magnetic monopole) description. We show that covariant spin precession lacks a unique form and discuss connection to $g - 2$ anomaly. We consider variational action principle and find that a consistent extension of Lorentz force to include magnetic spin force is not straightforward. We look at non-covariant particle dynamics, and present a short introduction to dynamics of (neutral) particles hit by a laser pulse of arbitrary shape.
↳ physics.class-phhep-phphysics.acc-phphysics.plasm-phEPJC(2018)·27 citations
52*
Planck 2015 constraints on the non-flat $ϕ$ CDM inflation model
Junpei Ooba🇯🇵 · Bharat Ratra🇺🇸 · Naoshi Sugiyama🇯🇵
We perform Markov chain Monte Carlo analyses to put constraints on the non-flat $ϕ$ CDM inflation model using Planck 2015 cosmic microwave background (CMB) anisotropy data and baryon acoustic oscillation distance measurements. The $ϕ$ CDM model is a consistent dynamical dark energy model in which the currently accelerating cosmological expansion is powered by a scalar field $ϕ$ slowly rolling down an inverse power-law potential energy density. We also use a physically consistent power spectrum for energy density inhomogeneities in this non-flat model. We find that, like the closed- $Λ$ CDM and closed-XCDM models, the closed- $ϕ$ CDM model provides a better fit to the lower multipole region of the CMB temperature anisotropy data compared to that provided by the tilted flat- $Λ$ CDM model. Also, like the other closed models, this model reduces the tension between the Planck and the weak lensing $σ_{8}$ constraints. However, the higher multipole region of the CMB temperature anisotropy data are better fit by the tilted flat- $Λ$ CDM model than by the closed models.
↳ astro-ph.COgr-qchep-phApJ(2018)·77 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.