Tue·Jul 28, 2015Tuesday·July 28, 2015

1. 01*

   Vector boson production at hadron colliders: transverse-momentum resummation and leptonic decay

   Stefano Catani🇮🇹 · Daniel de Florian🇦🇷 · Giancarlo Ferrera🇮🇹 · Massimiliano Grazzini🇨🇭

   We consider the transverse-momentum ($q_T$) distribution of Drell-Yan lepton pairs produced, via $W$ and $Z/{\gamma }^{\ast }$ decay, in hadronic collisions. At small values of $q_T$, we resum the logarithmically-enhanced perturbative QCD contributions up to next-to-next-to-leading logarithmic accuracy. Resummed results are consistently combined with the known $\mathcal{O}({\alpha }_S^2)$ fixed-order results at intermediate and large values of $q_T$. Our calculation includes the leptonic decay of the vector boson with the corresponding spin correlations, the finite-width effects and the full dependence on the final-state lepton(s) kinematics. The computation is encoded in the numerical program DYRes, which allows the user to apply arbitrary kinematical cuts on the final-state leptons and to compute the corresponding distributions in the form of bin histograms. We present a comparison of our results with some of the available LHC data. The inclusion of the leptonic decay in the resummed calculation requires a theoretical discussion on the $q_T$ recoil due to the transverse momentum of the produced vector boson. We present a $q_T$ recoil procedure that is directly applicable to $q_T$ resummed calculations for generic production processes of high-mass systems in hadron collisions.

   hep-phhep-exJHEP(2015)·190 citations
2. 02*

   Exclusive $J/\psi$ and ${\rm Y}$ photoproduction and the low $x$ gluon

   S.P. Jones🇩🇪 · A.D. Martin🇬🇧 · M.G. Ryskin🇷🇺 · T. Teubner🇬🇧

   We study exclusive vector meson photoproduction, $\gamma p\to V+p$ with $V=J/\psi$ or ${\rm Y}$, at NLO in collinear factorisation, in order to examine what may be learnt about the gluon distribution at very low $x$. We examine the factorisation scale dependence of the predictions. We argue that, using knowledge of the NLO corrections, terms enhanced by a large $\ln (1/\xi )$ can be reabsorbed in the LO part by a choice of the factorisation scale. (In these exclusive processes $\xi$ takes the role of Bjorken-$x$.) Then, the scale dependence coming from the remaining NLO contributions has no $\ln (1/\xi )$ enhancements. As a result, we find that predictions for the amplitude of ${\rm Y}$ production are stable to within about $\pm 15\%$. This will allow data for the exclusive process $pp\to p{\rm Y}p$ at the LHC, particularly from LHCb, to be included in global parton analyses to constrain the gluon PDF down to $x\sim 10^{-5}$. Moreover, the study of exclusive $J/\psi$ photoproduction indicates that the gluon density found in the recent global PDF analyses is too small at low $x$ and low scales.

   hep-phJ.Phys.G(2016)·80 citations
3. 03*

   Suppression of baryon diffusion and transport in a baryon rich strongly coupled quark-gluon plasma

   Romulo Rougemont (Sao Paulo U.)🇧🇷 · Jorge Noronha (Sao Paulo U. & Columbia U.)🇧🇷 · Jacquelyn Noronha-Hostler (Columbia U.)🇺🇸

   Five dimensional black hole solutions that describe the QCD crossover transition seen in $(2+1)$-flavor lattice QCD calculations at zero and nonzero baryon densities are used to obtain predictions for the baryon susceptibility, baryon conductivity, baryon diffusion constant, and thermal conductivity of the strongly coupled quark-gluon plasma in the range of temperatures $130\text{MeV}\le T\le 300\text{MeV}$ and baryon chemical potentials $0\le {\mu }_B\le 400\text{MeV}$. Diffusive transport is predicted to be suppressed in this region of the QCD phase diagram, which is consistent with the existence of a critical end point at larger baryon densities. We also calculate the fourth-order baryon susceptibility at zero baryon chemical potential and find quantitative agreement with recent lattice results. The baryon transport coefficients computed in this paper can be readily implemented in state-of-the-art hydrodynamic codes used to investigate the dense QGP currently produced at RHIC's low energy beam scan.

   hep-phhep-thnucl-exnucl-thPRL(2015)·96 citations
4. 04*

   Pseudoscalar Portal Dark Matter and New Signatures of Vector-like Fermions

   JiJi Fan🇺🇸 · Savvas M. Koushiappas🇺🇸 · Greg Landsberg🇺🇸

   Fermionic dark matter interacting with the Standard Model sector through a pseudoscalar portal could evade the direct detection constraints while preserving a WIMP miracle. We study the LHC constraints on the pseudoscalar production in simplified models with the pseudoscalar either dominantly coupled to b quarks or tau leptons and explore their implications for the GeV excesses in gamma ray observations. We also investigate models with new vector-like fermions that could realize the simplified models of pseudoscalar portal dark matter. These models yield new decay channels and signatures of vector-like fermions, for instance, bbb, btautau, and tautautau resonances. Some of the signatures have already been strongly constrained by the existing LHC searches and the parameter space fitting the gamma ray excess is further restricted. On the other hand, the pure tau-rich final state is only weakly constrained so far due to the small electroweak production rate.

   hep-phJHEP(2016)·31 citations
5. 05*

   Probing a light CP-odd scalar in di-top-associated production at the LHC

   Mirkoantonio Casolino🇪🇸 · Trisha Farooque🇪🇸 · Aurelio Juste🇪🇸 · Tao Liu🇨🇳 · Michael Spannowsky🇬🇧

   CP-odd scalars are an integral part of many extensions of the Standard Model. Recently, electroweak-scale pseudoscalars have received increased attention in explaining the diffuse gamma-ray excess from the Galactic Centre. Elusive due to absence of direct couplings to gauge bosons, these particles receive only weak constraints from direct searches at LEP or searches performed during the first LHC runs. We investigate the LHC's sensitivity in observing a CP-odd scalar in di-top associated production in the mass range $20\le m_A\le 100$ GeV using jet substructure based reconstruction techniques. We parametrise the scalar's interactions using a simplified model approach and relate the obtained upper limits to couplings within type-I and type-II 2HDMs as well as the NMSSM. We find that in di-top-associated production, experiments at the LHC can set tight limits on CP-odd scalars that fit the Galactic Centre excess. However, direct sensitivity to light CP-odd scalars from the NMSSM proves to remain challenging.

   hep-phhep-exEPJC(2015)·43 citations
6. 06*

   Global analysis of the pMSSM in light of the Fermi GeV excess: prospects for the LHC Run-II and astroparticle experiments

   Gianfranco Bertone (GRAPPA/Amsterdam)🇳🇱 · Francesca Calore (GRAPPA/Amsterdam)🇳🇱 · Sascha Caron (IMAPP/Amsterdam)🇳🇱 · Roberto Ruiz de Austri (IFIC/Valencia)🇪🇸 · Jong Soo Kim (UAM/Madrid)🇪🇸 · Roberto Trotta (ICIC/Imperial)🇬🇧 · Christoph Weniger (GRAPPA/Amsterdam)🇳🇱

   We present a new global fit of the 19-dimensional phenomenological Minimal Supersymmetric Standard Model (pMSSM-19) that comply with all the latest experimental results from dark matter indirect, direct and accelerator dark matter searches. We show that the model provides a satisfactory explanation of the excess of gamma-rays from the Galactic centre observed by the Fermi~Large Area Telescope, assuming that it is produced by the annihilation of neutralinos in the Milky Way halo. We identify two regions that pass all the constraints: the first corresponds to neutralinos with a mass ~80-100 GeV annihilating into WW with a branching ratio of 95% ; the second to heavier neutralinos, with mass ~180-200 GeV annihilating into t tbar with a branching ratio of 87%. We show that neutralinos compatible with the Galactic centre GeV excess will soon be within the reach of LHC run-II -- notably through searches for charginos and neutralinos, squarks and light smuons -- and of Xenon1T, thanks to its unprecedented sensitivity to spin-dependent cross-section off neutrons.

   hep-phJCAP(2016)·77 citations
7. 07*

   Higgs CP Violation from Vectorlike Quarks

   Chien-Yi Chen🇺🇸 · S. Dawson🇺🇸 · Yue Zhang🇺🇸

   We explore CP violating aspects in the Higgs sector of models where new vectorlike quarks carry Yukawa couplings mainly to the third generation quarks of the Standard Model. We point out that in the simplest model, Higgs CP violating interactions only exist in the hWW channel. At low energy, we find that rare B decays can place similarly strong constraints as those from electric dipole moments on the source of CP violation. These observations offer a new handle to discriminate from other Higgs CP violating scenarios such as scalar sector extensions of the Standard Model, and imply an interesting future interplay among limits from different experiments.

   hep-phPRD(2015)·9 citations
8. 08*

   Generating ${\theta }_{13}$ from sterile neutrinos in $\mu -\tau$ symmetric models

   Diana C. Rivera-Agudelo🇲🇽 · Abdel Pérez-Lorenzana🇲🇽

   The smallness of the ${\theta }_{13}$ mixing angle as observed in neutrino oscillation experiments can be understood through an approximated $\mu -\tau$ exchange symmetry in the neutrino mass matrix. Using recent oscillation neutrino data, but assuming no \textit{CP} violation, we study $\mu -\tau$ breaking parameter space to establish the conditions under which such a breaking could have a perturbative origin. According to the so-obtained conditions, we suggest that a sterile neutrino, matching LSND/MiniBooNE neutrino oscillation results, could provide the necessary ingredients to properly fix atmospheric and ${\theta }_{13}$ mixing angles to observable values, without exceeding the sterile neutrino fraction bound in solar oscillations. In such a scenario, we analyze the general effect of a fourth neutrino on the prediction for the effective $m_{ee}$ majorana mass parameter.

   hep-phPRD(2015)·27 citations
9. 09*

   Stellar matter with pseudoscalar condensates

   A. A. Andrianov🇷🇺 · V. A. Andrianov🇷🇺 · D. Espriu🇪🇸 · S. S. Kolevatov🇷🇺

   In this work we consider how the appearance of gradients of pseudoscalar condensates in dense systems may possibly influence the transport properties of photons in such a medium as well as other thermodynamic characteristics. We adopt the hypothesis that in regions where the pseudoscalar density gradient is large the properties of photons and fermions are governed by the usual lagrangian extended with a Chern-Simons interaction for photons and a constant axial field for fermions. We find that these new pieces in the lagrangian produce non-trivial reflection coefficients both for photons and fermions when entering or leaving a region where the pseudoscalar has a non-zero gradient. A varying pseudoscalar density may also lead to instability of some fermion and boson modes and modify some properties of the Fermi sea. We speculate that some of these modifications could influence the cooling rate of stellar matter (for instance in compact stars) and have other observable consequences. While quantitative results may depend on precise astrophysical details most of the consequences are quite universal and consideration should be given to this possibility.

   hep-phastro-ph.SRnucl-thEPJC(2016)·4 citations
10. 10*

    Heavy Vector Partners of the Light Composite Higgs

    Kenneth Lane🇺🇸 · Lukas Pritchett🇺🇸

    If the Higgs boson $H(125)$ is a composite due to new strong interactions at high energy, it has spin-one partners, ${\rho }_H$ and $a_H$, analogous to the $\rho$ and $a_1$ mesons of QCD. These bosons are heavy, their mass determined by the strong interaction scale. The strongly interacting particles light enough for ${\rho }_H$ and $a_H$ to decay to are the longitudinal weak bosons $V_L=W_L,Z_L$ and the Higgs boson $H$. These decay signatures are consistent with resonant diboson excesses recently reported near 2 TeV by ATLAS and CMS. We calculate $\sigma \times BR({\rho }_H\to VV)=$ few fb and $\sigma \times BR(a_H\to VH)=$ 0.5-1 fb at $\sqrt{s}=$ 8 TeV, increasing by a factor of 5-7 at 13 TeV. Other tests of the hypothesis of the strong-interaction nature of the diboson resonances are suggested.

    hep-phhep-exPLB(2016)·30 citations
11. 11*

    One-loop QCD correction to top pair production in the littlest Higgs model with T-parity at the LHC

    Bingfang Yang🇨🇳 · Ning Liu🇨🇳

    In this work, we investigate the one-loop QCD correction to top pair production in the littlest Higgs model with T-parity at the LHC. We calculate the relative correction of the top pair production cross section and top-antitop spin correlation at the LHC for $\sqrt{s}=8,14$ TeV. We find that the relative corrections of top pair production cross section can reach about $-0.35\%$, and the top-antitop spin correlation can reach $1.7\%$($2\%$) at the 8(14) TeV LHC in the favorable parameter space.

    hep-phEPL(2015)·0 citations
12. 12*

    Resummation of double collinear logs in BK evolution versus HERA data

    Javier L. Albacete🇪🇸

    We present a global fit to HERA data on the reduced cross section measured in electron-proton collisions in the region of small Bjorken-$x$: $x\le x_0=10^{-2}$ and moderate to high values of the virtuality $Q^2<Q_{max}^2=650$ GeV${}^2$. The main dynamical ingredients in the fits are two recently proposed improved BK equations for the description of the small-$x$ evolution of the dipole scattering amplitude. These two new equations provide an all-order resummation of double collinear logarithms that arise beyond leading logarithmic accuracy. We show that a very good description of data is possible in both cases, provided the parent dipole or smallest dipole prescriptions are employed for the running of the coupling.

    hep-phNPA(2017)·43 citations
13. 13*

    Further study of the $N\Omega$ dibaryon within constituent quark models

    Hongxia Huang🇨🇳 · Jialun Ping🇨🇳 · Fan Wang🇨🇳

    Inspired by the discovery of the dibaryon $d^{\ast }$ and the experimental search of $N\Omega$ dibaryon with the STAR data, we study the strange dibaryon $N\Omega$ further in the framework of quark delocalization color screening model and chiral quark model. We have shown $N\Omega$ is a narrow resonance in $\Lambda \Xi$ D-wave scattering before. However, the $\Lambda$-$\Xi$ scattering data analysis is quite complicated. Here we calculate the low-energy $N\Omega$ scattering phase shifts, scattering length, effective range and binding energy to provide another approach of STAR data analysis. Our results show there exists an $N\Omega$ "bound" state, which can be observed by the $N$-$\Omega$ correlation analysis with RHIC and LHC data, or by the new developed automatic scanning system at J-PARC. Besides, we also find that the hidden color channel-coupling is important for the $N\Omega$ system to develop intermediate-range attraction.

    hep-phnucl-thPRC(2015)·41 citations
14. 14*

    Lepton Flavour Violating top decays at the LHC

    Sacha Davidson🇫🇷 · Michelangelo L. Mangano🇨🇭 · Stephane Perries🇫🇷 · Viola Sordini🇫🇷

    We consider lepton flavour violating decays of the top quark, mediated by four-fermion operators. We compile constraints on a complete set of SU(3)*U(1)-invariant operators, arising from their loop contributions to rare decays and from HERA's single top search. The bounds on e-mu flavour change are more restrictive than l-tau; nonetheless the top could decay to a jet $+e\bar{\mu }$ with a branching ratio of order $10^{-3}$. We estimate that the currently available LHC data (20 inverse-fb at 8 TeV) could be sensitive to $BR(t\to e\bar{\mu }$+ jet) $\sim 6\times 10^{-5}$, and extrapolate that 100 inverse-fb at 13 TeV could reach a sensitivity of $\sim 1\times 10^{-5}$.

    hep-phEPJC(2015)·47 citations
15. 15*

    Higgs boson parity. Discussion of the experiment

    Ilya Ginzburg🇷🇺

    Recently CMS and ATLAS announced that they have measured the Higgs boson parity. In fact, these results allow to define parity for a small class of models only. For the majority of models the used approach provides no information about Higgs parity.

    hep-ph0 citations
16. 16*

    Remarks on the static dipole-dipole potential at large distances

    Matteo Giordano (Debrecen, Inst. Nucl. Res.)🇭🇺 · Enrico Meggiolaro (Pisa U. & INFN, Pisa)🇮🇹

    We determine the large-distance behaviour of the static dipole-dipole potential for a wide class of gauge theories on nonperturbative grounds, exploiting only general properties of the theory. In the case of QCD, we recover the known results in the regime of small dipole sizes, and discuss recent nonperturbative calculations. Moreover, we discuss the case of pure-gauge theories, and compare our prediction with the available lattice results.

    hep-phhep-lathep-thPRD(2015)·3 citations
17. 17*

    Dual condensates at finite isospin chemical potential

    Zhao Zhang🇨🇳 · Qing Miao🇨🇳

    The dual observables as order parameters for center symmetry are tested at finite isospin chemical potential ${\mu }_I$ in a Polyakov-loop enhanced chiral model of QCD with physical quark masses. As a counterpart of the dressed Polyakov-loop, the first Fourier moment of pion condensate is introduced for ${\mu }_I>m_{\pi }/2$ under the temporal twisted boundary conditions for quarks. We demonstrate that this dual condensate exhibits the similar temperature dependence as the conventional Polyakov-loop. We confirm that its rapid increase with $T$ is driven by the evaporating of pion condensation. On the other hand, the dressed Polyakov-loop shows abnormal thermal behavior, which even decreases with $T$ at low temperatures due to the influence of pion condensate. We thus argue that in QCD the critical temperature extracting from a dual observable may have nothing to do with the quark confinement-deconfinement transition if the quark mass is very small.

    hep-phPLB(2016)·13 citations
18. 18*

    Exotic mesons with hidden charm as diquark-antidiquark states

    V.V. Anisovich🇷🇺 · M.A. Matveev🇷🇺 · A.V. Sarantsev🇩🇪 · A.N. Semenova🇷🇺

    Exotic mesons with hidden strange ($s\bar{s}$) and heavy quark pairs ($Q\bar{Q}$), where $Q=c,b$, are considered as diquark-antidiquark systems, $(Qs)(\bar{Q}\bar{s})$. Taking into account that these states can recombinate into two-meson ones, we study the interplay of these states in terms of the dispersion relation D-function technique. The classification of exotic mesons is discussed, coefficients for decay modes are given, predictions for new states are presented. The nonet structure for $((Qq)(\bar{Q}\bar{q})$, ($(Qs)(\bar{Q}\bar{s}$)), ($(Qq)(\bar{Q}\bar{s}))$- states ($q=u,d$) is suggested.

    hep-phInt.J.Mod.Phys.A(2015)·26 citations
19. 19*

    D Production In p-p and d-Au Collisions

    Leonard S. Kisslinger🇺🇸 · Ming X. Liu🇺🇸 · Patrick McGaughey🇺🇸

    This is an extension of our previous work on $J/\Psi$, ${\Psi }^{\prime }(2S)$, ${\rm Y}(nS)$ production in p-p and A-A collisions to the production of $D^{+}(c\bar{d}),D^o(c\bar{u})$, with the main new aspect being the fragmentation probability, $D_{c\to c\bar{q}}$, which has been calculated almost two decades ago. The rapidity cross sections for $D^{+}(c\bar{d}),D^o(c\bar{u})$ production from both p-p and d-AU collisions is estimated.

    hep-phInt.J.Theor.Phys.(2016)·4 citations
20. 20*

    Heavy quark potential from deformed $Ad{S}_5$ models

    Zi-qiang Zhang🇨🇳 · De-fu Hou🇨🇳 · Gang Chen🇨🇳

    In this paper, we investigate the heavy quark potential in some holographic QCD models. The calculation relies on a modified renormalization scheme mentioned in a previous work of Albacete et al. After studying the heavy quark potential in Pirner-Galow model and Andreev-Zakharov model, we extend the discussion to a general deformed $Ad{S}_5$ case. It is shown that the obtained potential is negative definite for all quark-antiquark separations, differs from that using the usual renormalization scheme.

    hep-phNPA(2017)·14 citations
21. 21*

    NLO QCD and EW corrections to $WW$+jet production with leptonic $W$-boson decays at LHC

    Li Wei-Hua🇨🇳 · Zhang Ren-You🇨🇳 · Ma Wen-Gan🇨🇳 · Guo Lei🇨🇳 · Li Xiao-Zhou🇨🇳 · Zhang Yu🇨🇳

    We present the complete next-to-leading order (NLO) QCD and NLO electroweak (EW) corrections to the $W$-boson pair production associated with a hard jet at the LHC including the spin correlated $W$-boson leptonic decays. The dependence of the leading order (LO) and NLO corrected cross sections on the jet transverse momentum cut is investigated. In dealing with the subsequent resonant $W$-boson decays, we adopt the {\sc MadSpin} method where the spin correlation effect is included. We also provide the LO and NLO corrected distributions of the transverse momenta and rapidities of final products. The results show that the NLO EW correction is significant in high transverse momentum region due to the EW Sudakov effect.

    hep-phPRD(2015)·11 citations
22. 22*

    SM vacuum stability and the Weyl consistency conditions: Counting to three

    Jens Krog🇩🇰

    We demonstrate how a new perturbative ordering may result from the structure of the Weyl anomaly. Respecting the abelian nature of the Weyl anomaly at the lowest order enforces the use of beta functions calculated to a different loop order for different types of couplings. These consistency conditions are found to be satisfied by the renormalization group equations of the standard model, and we perform an analysis of the vacuum stability of the Higgs potential respecting the consistency conditions and compare to the previous results. Hints toward unknown structure in the standard model renormalization group equations are found, although the vacuum stability results are in agreement with previous estimates.

    hep-phPoS(2015)·0 citations
23. 23*

    Extra $Z^{\prime }$s and $W^{\prime }$s in Heterotic--String Derived Models

    Alon E. Faraggi🇬🇧 · Marco Guzzi🇬🇧

    The ATLAS collaboration recently recorded possible excess in the di--boson production at the di--boson invariant mass at around 2 TeV. Such an excess may be produced if there exist additional $Z^{\prime }$ and/or $W^{\prime }$ at that scale. We survey the extra $Z^{\prime }$s and $W^{\prime }$s that may arise from semi--realistic heterotic string vacua in the free fermionic formulation in seven distinct cases including: $U(1{)}_{Z^{\prime }}\in SO(10)$; family universal $U(1{)}_{Z^{\prime }}$ not in $SO(10)$; non--universal $U(1{)}_{Z^{\prime }}$; hidden sector $U(1)$ symmetries and kinetic mixing; left--right symmetric models; Pati--Salam models; leptophobic and custodial symmetries. Each case has a distinct signature associated with the extra symmetry breaking scale. In one of the cases we explore the discovery potential at the LHC using resonant leptoproduction. Existence of extra vector boson with the reported properties will significantly constrain the space of allowed string vacua.

    hep-phhep-thEPJC(2015)·42 citations
24. 24*

    Photoproduction of $a_0(980)$ and $f_0(980)$

    A. Donnachie🇬🇧 · Yu S. Kalashnikova🇷🇺

    There is no generally accepted view of the structure of the light-quark non-strange scalar mesons. A variety of models have been proposed that encompass $qq\bar{q}\bar{q}$, molecular, $q\bar{q}$ and glueball states in various combinations. Previously we considered scalar-meson photoproduction in a simple Regge-pole model and showed that it was experimentally viable. Recent data on the photoproduction of $a_0(980)$ and $f_0(980)$ confirm this. We extend our model to incorporate Regge cuts, based on our knowledge of ${\pi }^0$ photoproduction. The theoretical predictions are compared to the $a_0(980)$ and $f_0(980)$ photoproduction data.

    hep-phPRC(2016)·28 citations
25. 25*

    Looking for supersymmetry: ~1 Tev WIMP and the power of complementarity in LHC and dark matter searches

    K. Kowalska🇵🇱 · L. Roszkowski🇵🇱 · E.M. Sessolo🇵🇱 · S. Trojanowski🇵🇱 · A.J. Williams🇵🇱

    Some doubts have been expressed about low energy supersymmetry (SUSY) following the first run of the LHC. In this talk I will try to present a more upbeat view based on data, rather than theoretical expectations. In particular, I will make the following points: (a) in my opinion the most attractive candidate for dark matter (DM) is now the lightest neutralino with mass around 1 TeV and with well defined properties (a nearly pure higgsino). This follows primarily from a combination of the properties of the discovered Higgs boson, in particular its mass close to 125 Gev, and the relic density of dark matter, and is most clearly visible in the context of unified, or constrained, SUSY frameworks, although the DM candidate is quite generic; (b) this DM candidate will be nearly fully tested in forthcoming one-tonne DM underground search detectors; (c) the CMSSM will be nearly fully tested in the next few years by a combination of expected data from LHC experiments and from direct DM searches, as well as potentially also by the Cherenkov Telescope Array; (d) if naturalness plays any real role in SUSY (which remains unclear), then the amount of fine tuning, which is very large in simple models like the CMSSM, can be significantly reduced (even down to 1 in 20) with properly selected boundary conditions at the unification scale; (e) the (g-2) muon anomaly can be accommodated not only in the context of the general MSSM but also of some unified SUSY models with some superpartners to be within reach of the LHC.

    hep-ph10 citations
26. 26*

    Testing the ${\chi }_{c1}p$ composite nature of the $P_c(4450)$

    Ulf-G. Meißner🇩🇪 · José A. Oller🇪🇸

    Making use of a recently proposed formalism, we analyze the composite nature of the $P_c(4450)$ resonance observed by LHCb. We show that the present data suggest that this state is almost entirely made of a ${\chi }_{c1}$ and a proton, due to the close proximity to this threshold. This also suppresses the decay modes into other, lighter channels, in our study represented by $J/\Psi p$. We further argue that this is very similar to the case of the scalar meson $f_0(980)$ which is located closely to the $K\bar{K}$ threshold and has a suppressed decay into the lighter $\pi \pi$ channel.

    hep-phhep-exhep-latnucl-thPLB(2015)·202 citations
27. 27*

    Cascading Multicriticality in Nonrelativistic Spontaneous Symmetry Breaking

    Tom Griffin🇬🇧 · Kevin T. Grosvenor🇺🇸 · Petr Horava🇺🇸 · Ziqi Yan🇺🇸

    Without Lorentz invariance, spontaneous global symmetry breaking can lead to multicritical Nambu-Goldstone modes with a higher-order low-energy dispersion $\omega \sim k^n$ ($n=2,3,\dots$), whose naturalness is protected by polynomial shift symmetries. Here we investigate the role of infrared divergences and the nonrelativistic generalization of the Coleman-Hohenberg-Mermin-Wagner (CHMW) theorem. We find novel cascading phenomena with large hierarchies between the scales at which the value of $n$ changes, leading to an evasion of the "no-go" consequences of the relativistic CHMW theorem.

    ↳ hep-thastro-ph.COcond-mat.supr-conhep-ph+2PRL(2015)·23 citations
28. 28*

    Dark matter vs. astrophysics in the interpretation of AMS-02 electron and positron data

    Mattia Di Mauro🇮🇹 · Fiorenza Donato🇮🇹 · Nicolao Fornengo🇮🇹 · Andrea Vittino🇮🇹

    We perform a detailed quantitative analysis of the recent AMS-02 electron and positron data. We investigate the interplay between the emission from primary astrophysical sources, namely Supernova Remnants and Pulsar Wind Nebulae, and the contribution from a dark matter annihilation or decay signal. Our aim is to assess the information that can be derived on dark matter properties when both dark matter and primary astrophysical sources are assumed to jointly contribute to the leptonic observables measured by the AMS-02 experiment. We investigate both the possibility to set robust constraints on the dark matter annihilation/decay rate and the possibility to look for dark matter signals within realistic models that take into account the full complexity of the astrophysical background. Our results show that AMS-02 data enable to probe efficiently vast regions of the dark matter parameter space and, in some cases, to set constraints on the dark matter annihilation/decay rate that are comparable or even stronger than the ones derived from other indirect detection channels.

    ↳ astro-ph.HEhep-phJCAP(2016)·84 citations
29. 29*

    Dark and visible matter distribution in Coma cluster: theory vs observations

    Ruslan Brilenkov🇺🇦 · Maxim Eingorn🇺🇸 · Alexander Zhuk🇺🇦

    We investigate dark and visible matter distribution in the Coma cluster in the case of the Navarro-Frenk-White (NFW) profile. A toy model where all galaxies in the cluster are concentrated inside a sphere of an effective radius $R_{\mathrm{eff}}$ is considered. It enables us to obtain the mean velocity dispersion as a function of $R_{\mathrm{eff}}$. We show that, within the observation accuracy of the NFW parameters, the calculated value of $R_{\mathrm{eff}}$ can be rather close to the observable cutoff of the galaxy distribution. Moreover, the comparison of our toy model with the observable data and simulations leads to the following preferable NFW parameters for the Coma cluster: $R_{200}\approx 1.77h^{-1}\mathrm{Mpc}=2.61\mathrm{Mpc}$, $c=3÷4$ and $M_{200}=1.29h^{-1}\times 10^{15}{M}_{\odot }$. In the Coma cluster the most of galaxies are concentrated inside a sphere of the effective radius $R_{\mathrm{eff}}\sim 3.7$ Mpc and the line-of-sight velocity dispersion is $1004\mathrm{km}{\mathrm{s}}^{-1}$.

    ↳ astro-ph.COastro-ph.GAgr-qchep-phAstron.Astrophys.Trans.(2017)·5 citations
30. 30*

    Hilbert series and operator bases with derivatives in effective field theories

    Brian Henning🇺🇸 · Xiaochuan Lu🇺🇸 · Tom Melia🇺🇸 · Hitoshi Murayama🇺🇸

    We introduce a systematic framework for counting and finding independent operators in effective field theories, taking into account the redundancies associated with use of the classical equations of motion and integration by parts. By working in momentum space, we show that the enumeration problem can be mapped onto that of understanding a polynomial ring in the field momenta. All-order information about the number of independent operators in an effective field theory is encoded in a geometrical object of the ring known as the Hilbert series. We obtain the Hilbert series for the theory of N real scalar fields in (0+1) dimensions--an example, free of space-time and internal symmetries, where aspects of our framework are most transparent. Although this is as simple a theory involving derivatives as one could imagine, it provides fruitful lessons to be carried into studies of more complicated theories: we find surprising and rich structure from an interplay between integration by parts and equations of motion and a connection with SL(2,C) representation theory which controls the structure of the operator basis.

    ↳ hep-thhep-phCommun.Math.Phys.(2016)·180 citations
31. 31*

    High-Scale Inflation and the Tensor Tilt

    Daniel Baumann🇬🇧 · Hayden Lee🇬🇧 · Guilherme L. Pimentel🇬🇧

    In this paper, we explore a novel observational signature of gravitational corrections during slow-roll inflation. We study the coupling of the inflaton field to higher-curvature tensors in models with a minimal breaking of conformal symmetry. In that case, the most general correction to the tensor two-point function is captured by a coupling to the square of the Weyl tensor. We show that these scenarios lead to a correction to the tilt of the tensor power spectrum and hence a violation of the tensor consistency condition. We arrive at the same conclusion through an analysis in conformal perturbation theory.

    ↳ hep-thastro-ph.COhep-phJHEP(2016)·73 citations
32. 32*

    Exact Teleparallel Gravity of Binary Black Holes

    W. El Hanafy🇪🇬 · G.G.L. Nashed🇪🇬

    An exact solution of two singularities in the teleparallel equivalent to general relativity theory has been obtained. A holographic visualization of the binary black holes (BBHs) space-time, due to the non vanishing torsion scalar field, has been given. The acceleration tensor of BBHs space-time has been calculated. The results identify the repulsive gravity zones of the BBHs field. The total conserved quantities of the BBHs has been evaluated. Possible gravitational radiation emission by the system has been calculated without assuming a weak field initial data.

    ↳ gr-qcastro-ph.HEhep-phhep-thAstrophys.Space Sci.(2016)·59 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.