Tue·Dec 15, 2015Tuesday·December 15, 2015

1. 01*

   Rôle of the pion electromagnetic form factor in the $\Delta (1232)\to {\gamma }^{\ast }N$ timelike transition

   G. Ramalho🇧🇷 · M.T Pena🇵🇹 · J. Weil🇩🇪 · H. van Hees🇩🇪 · U. Mosel🇩🇪

   The $\Delta (1232)\to {\gamma }^{\ast }N$ magnetic dipole form factor ($G_M^{\ast }$) is described here within a new covariant model that combines the valence quark core together with the pion cloud contributions. The pion cloud term is parameterized by two terms: one connected to the pion electromagnetic form factor, the other to the photon interaction with intermediate baryon states. The model can be used in studies of pp and heavy ion collisions. In the timelike region this new model improves the results obtained with a constant form factor model fixed at its value at zero momentum transfer. At the same time, and in contrast to the Iachello model, this new model predicts a peak for the transition form factor at the expected position, i.e. at the $\rho$ mass pole. We calculate the decay of the $\Delta \to \gamma N$ transition, the Dalitz decay ($\Delta \to e^{+}{e}^{-}N$), and the $\Delta$ mass distribution function. The impact of the model on dilepton spectra in pp collisions is also discussed.

   hep-phhep-exhep-latnucl-ex+1PRD(2016)·51 citations
2. 02*

   (In)Direct Detection of Boosted Dark Matter

   Kaustubh Agashe🇺🇸 · Yanou Cui🇨🇦 · Lina Necib🇺🇸 · Jesse Thaler🇺🇸

   We present a new multi-component dark matter model with a novel experimental signature that mimics neutral current interactions at neutrino detectors. In our model, the dark matter is composed of two particles, a heavier dominant component that annihilates to produce a boosted lighter component that we refer to as boosted dark matter. The lighter component is relativistic and scatters off electrons in neutrino experiments to produce Cherenkov light. This model combines the indirect detection of the dominant component with the direct detection of the boosted dark matter. Directionality can be used to distinguish the dark matter signal from the atmospheric neutrino background. We discuss the viable region of parameter space in current and future experiments.

   hep-phastro-ph.COhep-exJ.Phys.Conf.Ser.(2016)·11 citations
3. 03*

   Gluino Meets Flavored Naturalness

   Monika Blanke🇩🇪 · Benjamin Fuks🇫🇷 · Iftah Galon🇺🇸 · Gilad Perez🇮🇱

   We study constraints from LHC run I on squark and gluino masses in the presence of squark flavor violation. Inspired by the concept of `flavored naturalness', we focus on the impact of a non-zero stop-scharm mixing and mass splitting in the right-handed sector. To this end, we recast four searches of the ATLAS and CMS collaborations, dedicated either to third generation squarks, to gluino and squarks of the first two generations, or to charm-squarks. In the absence of extra structure, the mass of the gluino provides an additional source of fine tuning and is therefore important to consider within models of flavored naturalness that allow for relatively light squark states. When combining the searches, the resulting constraints in the plane of the lightest squark and gluino masses are rather stable with respect to the presence of flavor-violation, and do not allow for gluino masses of less than 1.2 TeV and squarks lighter than about 550 GeV. While these constraints are stringent, interesting models with sizable stop-scharm mixing and a relatively light squark state are still viable and could be observed in the near future.

   hep-phhep-exJHEP(2016)·13 citations
4. 04*

   Dark matter beams at LBNF

   Pilar Coloma🇺🇸 · Bogdan A. Dobrescu🇺🇸 · Claudia Frugiuele🇺🇸 · Roni Harnik🇺🇸

   High-intensity neutrino beam facilities may produce a beam of light dark matter when protons strike the target. Searches for such a dark matter beam using its scattering in a nearby detector must overcome the large neutrino background. We characterize the spatial and energy distributions of the dark matter and neutrino beams, focusing on their differences to enhance the sensitivity to dark matter. We find that a dark matter beam produced by a $Z^{\prime }$ boson in the GeV mass range is both broader and more energetic than the neutrino beam. The reach for dark matter is maximized for a detector sensitive to hard neutral-current scatterings, placed at a sizable angle off the neutrino beam axis. In the case of the Long-Baseline Neutrino Facility (LBNF), a detector placed at roughly 6 degrees off axis and at a distance of about 200 m from the target would be sensitive to $Z^{\prime }$ couplings as low as 0.05. This search can proceed symbiotically with neutrino measurements. We also show that the MiniBooNE and MicroBooNE detectors, which are on Fermilab's Booster beamline, happen to be at an optimal angle from the NuMI beam and could perform searches with existing data. This illustrates potential synergies between LBNF and the short-baseline neutrino program if the detectors are positioned appropriately.

   hep-phhep-exJHEP(2016)·78 citations
5. 05*

   Gluonic Structure of the Constituent Quark

   Nikolai Kochelev🇷🇺 · Hee-Jung Lee🇰🇷 · Baiyang Zhang🇨🇳 · Pengming Zhang🇨🇳

   Based on both the constituent quark picture and the instanton model for QCD vacuum, we calculate the unpolarized and polarized gluon distributions in the constituent quark and in the nucleon. Our approach consists of the two main steps. At the first step, we calculate the gluon distributions inside the constituent quark generated by the perturbative quark-gluon interaction, the non-perturbative quark-gluon interaction, and the non-perturbative quark-gluon-pion anomalous chromomagnetic interaction. The non-perturbative interactions are related to the existence of the instantons, strong topological fluctuations of gluon fields, in the QCD vacuum. At the second step, the convolution model is applied to derive the gluon distributions in the nucleon. A very important role of the pion field in producing the unpolarized and the polarized gluon distributions in the hadrons is discovered. We discuss a possible solution of the proton spin problem.

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

   Sensitivity of the decay $h\to Z{Z}^{\ast }\to Zl+l-$ to the Higgs self coupling through radiative corrections

   H. Castilla-Valdez🇲🇽 · C. G. Honorato🇲🇽 · A. Moyotl🇲🇽 · M. A. Perez🇲🇽

   We study the radiative corrections induced by the triple Higgs boson coupling $hhh$ in the three body decay $h\to Z{Z}^{\ast }\to Zl\bar{l}$. We show that these corrections are potentially sensitive to the specific value of this coupling in the Standard Model and the Two Higgs Doublet Model (2HDM). These effects may induce corrections to the integrated decay width of the three-body decay of order few percent in the 2HDM and thus open a new window to test the Higgs boson self interaction in physics beyond the standard model.

   hep-phPRD(2016)·10 citations
7. 07*

   Spontaneous Magnetization of Quark Matter in Inhomogeneous Chiral Phase

   Ryo Yoshiike🇯🇵 · Kazuya Nishiyama · Toshitaka Tatsumi🇯🇵

   Considering the density wave of scalar and pseudoscalar condensates, we study the response of quark matter to a weak external magnetic field. In an external magnetic field, the energy spectrum of the lowest Landau level becomes asymmetric about zero, which is closely related to chiral anomaly. This spectral asymmetry gives rise to spontaneous magnetization. This mechanism may be one of candidates for the origin of the strong magnetic field in magnetars. Furthermore, using the generalized Ginzburg-Landau(gGL) expansion, we show that magnetic susceptibility exhibits a peculiar feature

   hep-phActa Astron.Sin.Suppl.(2015)·0 citations
8. 08*

   Topological Aspects of the Imhomogeneous Chiral Phases and Implication on Compact Stars

   T.Tatsumi🇯🇵

   Recent studies of our group are reviewed about the inhomogeneous chiral phase. Appearance of the inhomogeneous chiral phase is a new paradigm in the field of the QCD phase diagram. We consider the dual-chiral-density-wave in the presence of the magnetic field. Some topological effect manifests in the form of spectral asymmetry of the quark single-particle energy.

   hep-ph0 citations
9. 09*

   Compositeness of Near Threshold Quasi-Bound States

   Yuki Kamiya🇯🇵 · Tetsuo Hyodo🇯🇵

   We study the compositeness of unstable hadrons which lie near the two-hadron threshold. In the framework of the effective field theory, we derive the relation between the compositeness of stable bound states with observables. We then extend this relation for the quasi-bound states with finite decay width. A prescription to interpret the complex value of the compositeness is presented. With this method, we show that Lambda(1405) is dominated by the Kbar N composite component and a_0(980) have only small Kbar K fraction.

   hep-phnucl-thAIP Conf.Proc.(2016)·0 citations
10. 10*

    An alternative subtraction scheme for NLO QCD calculations

    Tania Robens🇩🇪

    We discuss an alternative subtraction scheme for NLO QCD calculations, which is based on the splitting kernels of an improved parton shower. As an example, we show results for the C parameter of the process e+ e- to 3 jets at NLO used for the verification of this scheme.

    hep-phFrascati Phys.Ser.(2016)·0 citations
11. 11*

    Prospects for detection of target-dependent annual modulation in direct dark matter searches

    Eugenio Del Nobile🇺🇸 · Graciela B. Gelmini🇺🇸 · Samuel J. Witte🇺🇸

    Earth's rotation about the Sun produces an annual modulation in the expected scattering rate at direct dark matter detection experiments. The annual modulation as a function of the recoil energy $E_{\text{R}}$ imparted by the dark matter particle to a target nucleus is expected to vary depending on the detector material. However, for most interactions a change of variables from $E_{\text{R}}$ to $v_{\text{min}}$, the minimum speed a dark matter particle must have to impart a fixed $E_{\text{R}}$ to a target nucleus, produces an annual modulation independent of the target element. We recently showed that if the dark matter-nucleus cross section contains a non-factorizable target and dark matter velocity dependence, the annual modulation as a function of $v_{\text{min}}$ can be target dependent. Here we examine more extensively the necessary conditions for target-dependent modulation, its observability in present-day experiments, and the extent to which putative signals could identify a dark matter-nucleus differential cross section with a non-factorizable dependence on the dark matter velocity.

    hep-phastro-ph.COJCAP(2016)·21 citations
12. 12*

    CP Violation Tests of Alignment Models at LHCII

    Diptimoy Ghosh🇮🇱 · Paride Paradisi🇮🇹 · Gilad Perez🇮🇱 · Gabriele Spada🇮🇹

    We analyse the low-energy phenomenology of alignment models both model-independently and within supersymmetric (SUSY) scenarios focusing on their CP violation tests at LHCII. Assuming that New Physics (NP) contributes to K-Kbar and D-Dbar mixings only through non-renormalizable operators involving SU(2)_L quark-doublets, we derive model-independent correlations among CP violating observables of the two systems. Due to universality of CP violation in Delta F=1 processes the bound on CP violation in Kaon mixing generically leads to an upper bound on the size of CP violation in D mixing. Interestingly, this bound is similar in magnitude to the current sensitivity reached by the LHCb experiment which is starting now to probe the natural predictions of alignment models. Within SUSY, we perform an exact analytical computation of the full set of contributions for the D-Dbar mixing amplitude. We point out that chargino effects are comparable and often dominant with respect to gluino contributions making their inclusion in phenomenological analyses essential. As a byproduct, we clarify the limit of applicability of the commonly used mass insertion approximation in scenarios with quasi-degenerate and split squarks.

    hep-phhep-exJHEP(2016)·2 citations
13. 13*

    Recent developments in Monte-Carlo Event Generators

    Marek Schönherr🇨🇭

    With Run II of the LHC having started, the need for high precision theory predictions whose uncertainty matches that of the data to be taken necessitated a range of new developments in Monte-Carlo Event Generators. This talk will give an overview of the progress in recent years in the field and what can and cannot be expected from these newly written tools.

    hep-phEPJ Web Conf.(2016)·0 citations
14. 14*

    A scalar field coupled to a brane in ${\mathcal{M}}_4\times {\mathcal{S}}_1$. Part I: Kaluza-Klein spectrum and zero-mode localization

    A. Donini🇪🇸

    A toy model where a massless, real, scalar field $\Phi$ in a compact space-time ${\mathcal{M}}_4\times {\mathcal{S}}_1$ is coupled to a brane (parametrized as a $\delta$-function) through the unique relevant operator $\delta (y){\Phi }^2(x,y)$ is considered. The exact Kaluza-Klein spectrum of the model is computed for any value of the coupling between field and brane using the Burniston-Siewert method to solve analytically transcendental equations. The exact KK-spectrum of a model with a Brane-Localized Kinetic Term is also computed. Weak- and strong-coupling limits are derived, matching or extending mathematically equivalent existing results. For a negative coupling, the would-be zero-mode ${\psi }_{0^{-}}^e$ is found to localize into the brane, behaving as an effective four-dimensional field. The 4-dimensional KK-decomposition of the model once a renormalizable cubic self-interaction ${\Phi }^3(x,y)$ is added to the action is derived computing the overlaps between the KK-modes. It is found that the localized would-be zero-mode ${\psi }_{0^{-}}^e$ decouples from the massive KK-spectrum in the limit of large brane-to-bulk coupling.

    hep-ph1 citation
15. 15*

    A Model of the Matter-antimatter Asymmetry and Cold Dark Matter with $U(1{)}_{B-L}\otimes U(1{)}_D$

    Wei-Min Yang🇨🇳

    I suggest an effective model between the GUT and the electroweak scale. It only introduces the two symmetries of $U(1{)}_{B-L}$ and $U(1{)}_D$ besides the SM groups. The two symmetries are individually broken at the reheating temperature of the universe of $10^{12}$ GeV and the scale of $3\sim 4$ TeV. The model can simultaneously accommodate the tiny neutrino masses, the matter-antimatter asymmetry and the cold dark matter (CDM). In particular, the model gives some interesting results and predictions, for instance, the neutrinos are Dirac nature and their masses are related to the $U(1{)}_D$ breaking, the size of the matter-antimatter asymmetry is closely related to the mass hierarchy of the quarks and charged leptons, the CDM mass is probably in the range of $250\sim 350$ GeV. Finally, it is feasible to test the model in future collider experiments.

    hep-phPLB(2016)·5 citations
16. 16*

    ${\Lambda }_b\to ({\Lambda }_c,p)\tau \nu$ decays within standard model and beyond

    Rupak Dutta🇮🇳

    Deviations from the standard model prediction have been observed in several leptonic and semileptonic $B$ meson decays to $\tau \nu$ final states mediated via $b\to u$ and $b\to c$ charged current interactions. The measured value of ratio of branching ratios $R_{\pi }^l$ of $B^{-}\to {\tau }^{-}{\nu }_{\tau }$ to $B^0\to {\pi }^{+}{\text{l}}^{-}\nu$ decays, where $l=(e,\mu )$, is larger than the standard model prediction by more than a factor of two. Similarly, a combined excess of $3.9\sigma$ from the standard model expectation has been reported by HFAG for the values of $R_D$ and $R_{D^{\ast }}$, where $R_{D,D^{\ast }}$ represents the ratio of branching ratios of $B\to (D,D^{\ast })\tau \nu$ to corresponding $B\to (D,D^{\ast })l\nu$ decays, respectively. Very recently, hint of lepton flavor violation has been observed in the ratio of branching fractions of $B\to K{e}^{+}{e}^{-}$ to $B\to K{\mu }^{+}{\mu }^{-}$ decays as well. In this context, we employ an effective Lagrangian approach to study the decay branching fractions and the ratio of branching fractions of ${\Lambda }_b\to {\Lambda }_{c}l\nu$ and ${\Lambda }_b\to pl\nu$ decays within the standard model and beyond. We constrain the new physics parameter space using the existing experimental data on $R_D$, $R_{D^{\ast }}$, and $R_{\pi }^l$. We give predictions for various observables in the context of various new physics scenarios.

    hep-phPRD(2016)·83 citations
17. 17*

    Relativistic five-quark equations and the LHCb pentaquarks

    S.M. Gerasyuta🇷🇺 · V.I. Kochkin🇷🇺

    The relativistic five-quark equations are found in the framework of the dispersion relation technique. The solutions of these equations using the method based on the extraction of the leading singularities of the amplitudes are obtained. The five-quark amplitudes for the hidden-charm pentaquarks including the u, d, c - quarks are calculated. The poles of these amplitudes determine the masses of pentaquarks. The masses of pentaquarks with JP=3/2-, 5/2+ are calculated.

    hep-ph8 citations
18. 18*

    $B^0\to D^0{\bar{D}}^0{K}^0$, $B^{+}\to D^0{\bar{D}}^0{K}^{+}$ and the scalar $D\bar{D}$ bound state

    L. R. Dai🇨🇳 · Ju-Jun Xie🇨🇳 · E. Oset🇪🇸

    We study the $B^0$ decay to $D^0{\bar{D}}^0{K}^0$ based on the chiral unitary model that generates the X(3720) resonance, and make predictions for the $D^0{\bar{D}}^0$ invariant mass distribution. From the shape of the distribution, the existence of the resonance below threshold could be induced. We also predict the rate of production of the X(3720) resonance to the $D^0{\bar{D}}^0$ mass distribution with no free parameters.

    hep-phnucl-thEPJC(2016)·31 citations
19. 19*

    Singlet fermion Dark Matter within Left-Right Model

    Sudhanwa Patra🇮🇳 · Soumya Rao🇦🇺

    We discuss singlet fermion dark matter within a left-right symmetric model promoting baryon and lepton numbers as separate gauge symmetries. We add a simple Dirac fermionic dark matter singlet under $SU(2{)}_{L,R}$ with nonzero and equal baryon and lepton number which ensures electric charge neutrality. Such a dark matter candidate interacts with SM particles through the extra $Z_{B,\ell }$ gauge bosons. This can give rise to a dark matter particle of a few hundred GeV that couples to $\sim$ TeV scale gauge bosons to give the correct relic density. This model thus accommodates TeV scale $Z_{B,\ell }$ gauge bosons and other low scale BSM particles, which can be easily probed at LHC.

    hep-phPLB(2016)·14 citations
20. 20*

    Chiral and Deconfining Phase Transitions from Holographic QCD Study

    Zhen Fang🇨🇳 · Song He🇩🇪 · Danning Li🇨🇳

    A first attempt to accommodate the chiral and deconfining phase transitions of QCD in the bottom-up holographic framework is given. We constrain the relation between dilaton field $\varphi$ and metric warp factor $A_e$ and get several reasonable models in the Einstein-Dilaton system. Using the potential reconstruction approach, we solve the corresponding gravity background. Then we fit the background-related parameters by comparing the equation of state with the two-flavor lattice QCD results. After that we study the temperature dependent behavior of Polyakov loop and chiral condensate under those background solutions. We find that the results are in good agreement with the two-flavor lattice results. All the studies about the equation of state, the Polyakov loop and the chiral condensate signal crossover behavior of the phase transitions, which is consistent with the current understanding on the QCD phase transitions with physical quark mass. Furthermore, the extracted transition temperatures are comparable with the two-flavor lattice QCD results.

    hep-phNPB(2016)·67 citations
21. 21*

    Quantum radiation reaction: from interference to incoherence

    Victor Dinu🇷🇴 · Chris Harvey🇸🇪 · Anton Ilderton🇸🇪 · Mattias Marklund🇸🇪 · Greger Torgrimsson🇸🇪

    We investigate quantum radiation reaction in laser-electron interactions across different energy and intensity regimes. Using a fully quantum approach which also accounts exactly for the effect of the strong laser pulse on the electron motion, we identify in particular a regime in which radiation reaction is dominated by quantum interference. We find signatures of quantum radiation reaction in the electron spectra which have no classical analogue and which cannot be captured by the incoherent approximations typically used in the high-intensity regime. These signatures are measurable with presently available laser and accelerator technology.

    hep-phphysics.plasm-phPRL(2016)·99 citations
22. 22*

    Probing Light Thermal Dark-Matter With a Higgs Portal Mediator

    Gordan Krnjaic🇺🇸

    We systematically study light (< few GeV) Dark Matter (DM) models that thermalize with visible matter through the Higgs portal and identify the remaining gaps in the viable parameter space. Such models require a comparably light scalar mediator that mixes with the Higgs to avoid DM overproduction and can be classified according to whether this mediator decays (in)visibly. In a representative benchmark model with Dirac fermion DM, we find that, even with conservative assumptions about the DM-mediator coupling and mass ratio, the regime in which the mediator is heavier than the DM is fully ruled out by a combination of collider, rare meson decay, and direct detection limits; future and planned experiments including NA62 can further improve sensitivity to scenarios in which the Higgs portal interaction does not determine the DM abundance. The opposite, regime in which the mediator is lighter than the DM and the latter annihilates to pairs of visibly-decaying mediators is still viable, but much of the parameter space is covered by rare meson decay, supernova cooling, beam dump, and direct detection constraints. Nearly all of these conclusions apply broadly to the simplest variations (e.g. scalar or asymmetric DM). Future experiments including SHiP, NEWS, and Super-CDMS SNOLAB can greatly improve coverage to this class of models.

    hep-phastro-ph.COhep-exPRD(2016)·329 citations
23. 23*

    Spin-independent interferences and spin-dependent interactions with scalar dark matter

    R. Martinez🇨🇴 · F. Ochoa🇨🇴

    We explore mechanisms of interferences under which the spin-independent interaction in the scattering of scalar dark matter with nucleus is suppressed. We offer a detailed derivation of the nuclear amplitudes based on the interactions with quarks in the framework of a nonuniversal $U(1{)}^{\prime }$ extension of the standard model. By assuming a range of parameters compatible with collider searches, electroweak observables and dark matter abundance, we find scenarios for destructive interferences with and without isospin symmetry. The model reveals solutions with mutually interfering scalar particles, canceling the effective spin-independent coupling with only scalar interactions, which requires an extra Higgs boson with mass $M_H>125$ GeV. The model also possesses scenarios with only vector interactions through two neutral gauge bosons, $Z$ and $Z^{\prime }$. Due to the nonuniversality of the $U(1{)}^{\prime }$ symmetry, we distinguish two family structures of the quark sector with different numerical predictions. In one case, we obtain cross sections that pass all the Xenon-based detector experiments. In the other case, limits from LUX experiment enclose an exclusion region for dark matter between $9$ and $800$ GeV. We examine a third scenario with isospin-violating couplings where interferences between scalar and vector boson exchanges cancel the scattering. We provide solutions where interactions with Xenon-based detectors is suppressed for light dark matter, below $6$ GeV, while interactions with Germanium- and Silicon-based detectors exhibit solutions up to the regions of interest for positive signals reported by CoGeNT and CDMS-Si experiments, and compatible with the observed DM relic density for DM mass in the range $8.3-10$ GeV. Spin-dependent interactions become the dominant source of scattering around the interference regions, where Maxwellian speed distribution is considered.

    hep-phJHEP(2016)·18 citations
24. 24*

    Study of the rare decay $J/\psi \to e^{+}{e}^{-}\varphi$

    Xing-Dao Guo🇨🇳 · Si-Run Xue🇨🇳 · Hong-Wei Ke🇨🇳 · Xue-Qian Li🇨🇳 · Qiang Zhao🇨🇳

    We study the decay process of $J/\psi \to e^{+}{e}^{-}\varphi$ where the relatively clean electromagnetic (EM) transitions appear at leading order at tree level while the hadronic contributions only emerge via hadronic loop transitions. We include the low-lying scalar $f_0(980)$ and pseudoscalar $\eta /{\eta }^{\prime }$ as the dominant contributions in the evaluation of the hadronic loop contributions. It is found that the hadronic effects are negligible comparing with the EM contributions. The decay width of $J/\psi \to e^{+}{e}^{-}\varphi$ is determined to be about $2.12\times 10^{-6}$ keV if there is no any other leading mechanism contributing, and this result will be tested by the BESIII experiment with a large data sample of $J/\psi$.

    hep-phCPC(2016)·3 citations
25. 25*

    Unified Fano-like interference picture for charmonium-like states $Y(4008)$, $Y(4260)$ and $Y(4360)$

    Dian-Yong Chen🇨🇳 · Xiang Liu🇨🇳 · Xue-Qian Li🇨🇳 · Hong-Wei Ke🇨🇳

    We propose that the unified Fano-like interference picture applies to $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ and $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3686)$, where $Y(4260)$ and $Y(4360)$ are observed, respectively, to provide a reasonable interpretation of the asymmetric lines hapes of $Y(4260)$ and $Y(4360)$ structures. Moreover, the Fano-like interference induces an extra broad structure $Y(4008)$ in $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}J/\psi$ as a companion peak to $Y(4260)$. Three charmonium-like states $Y(4008)$, $Y(4260)$ and $Y(4360)$ observed in $e^{+}{e}^{-}$ annihilation processes are not genuine resonances. Under this scenario, it is well explained why $Y(4008)$, $Y(4260)$ and $Y(4360)$ are absent in the experimental data of the $R$ value scan and missing in open-charm decay channels. Although the present work presents a typical application of the Fano-like interference in particle physics at the lower energy region, we have reason to believe that the Fano-like phenomena may exist in other processes such as $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (3770)$ and $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$, which will be accessible at BESIII and forthcoming BelleII.

    hep-phPRD(2016)·34 citations
26. 26*

    On atmospheric neutrino mass-squared difference in the precision era

    S. Bilenky🇷🇺

    With the measurement of the small parameter ${\sin }^2{\theta }_{13}$ experiments on the study of neutrino oscillations enter into a high precision era. I discuss here the problem of the definition of the atmospheric mass-squared difference which will be important for analysis of data of future experiments.

    hep-ph5 citations
27. 27*

    A rephasing invariant study of neutrino mixing

    S. H. Chiu🇹🇼

    We derive a set of renormalization group equations (RGE) for Dirac neutrinos using a rephasing invariant parametrization. The symmetric properties of these equations under flavor permutation facilitate the derivation of some exact and approximate RGE invariants. Even though the complete analytical solutions for the RGE are unavailable, we provide a numerical example that illustrate the evolution of the neutrino mixing parameters.

    hep-phPoS(2015)·0 citations
28. 28*

    A review of mu-tau flavor symmetry in neutrino physics

    Zhi-zhong Xing🇨🇳 · Zhen-hua Zhao🇨🇳

    Behind the observed pattern of lepton flavor mixing is a partial or approximate mu-tau flavor symmetry --- a milestone on our road to the true origin of neutrino masses and flavor structures. In this review article we first describe the features of mu-tau permutation and reflection symmetries, and then explore their various consequences on model building and neutrino phenomenology. We pay particular attention to soft mu-tau symmetry breaking, which is crucial for our deeper understanding of the fine effects of flavor mixing and CP violation.

    hep-phhep-exRept.Prog.Phys.(2016)·238 citations
29. 29*

    A non-boost-invariant solution of relativistic hydrodynamics in 1+3 dimensions

    Yoshitaka Hatta🇯🇵 · Bo-Wen Xiao🇨🇳 · Di-Lun Yang🇯🇵

    We present a new solution of relativistic hydrodynamics in 1+3 dimensions which depends on both the transverse coordinate and rapidity. At early times the flow expands dominantly longitudinally in a non-boost-invariant manner, and at late times it expands nearly spherically. These two regimes are shown to be related by symmetry. The effect of viscosity is also discussed.

    hep-phnucl-thPRD(2016)·5 citations
30. 30*

    Conversions of Bound Muons: Lepton Flavour Violation from Doubly Charged Scalars

    Tanja Geib🇩🇪 · Alexander Merle🇩🇪

    We present the first detailed computation of the conversion of a bound muon into an electron mediated by a doubly charged $SU(2)$ singlet scalar. Although such particles are not too exotic, up to now their contribution to $\mu$-$e$ conversion is unknown. We close this gap by presenting a detailed calculation, which will allow the reader not only to fully comprehend the discussion but also to generalise our results to similar cases if needed. We furthermore compare the predictions, for both the general case and for an example model featuring a neutrino mass at 2-loop level, to current experimental data and future sensitivities. We show that, depending on the explicit values of the couplings as well as on the actual future limits on the branching ratio, $\mu$-$e$ conversion may potentially yield a lower limit on the doubly charged singlet scalar mass which is stronger than what could be obtained by colliders. Our results considerably strengthen the case for low-energy lepton flavour violation searches being a very valuable addition to collider experiments.

    hep-phhep-exPRD(2016)·6 citations
31. 31*

    High-scale SUSY from an R-invariant New Inflation in the Landscape

    Masahiro Kawasaki🇯🇵 · Masaki Yamada🇯🇵 · Tsutomu T. Yanagida🇯🇵 · Norimi Yokozaki🇮🇹

    We provide an anthropic reason that the supersymmetry breaking scale is much higher than the electroweak scale as indicated by the null result of collider experiments and observed 125 GeV Higgs boson. We focus on a new inflation model as a typical low-scale inflation model that may be expected in the string landscape. In this model, the R-symmetry is broken at the minimum of the inflaton potential and its breaking scale is related to the reheating temperature. Once we admit that the anthropic principle requires thermal leptogenesis, we obtain a lower bound on gravitino mass, which is related to R-symmetry breaking scale. This scenario and resulting gravitino mass predict the consistent amplitude of density perturbations. We also find that string axions and saxions are consistently implemented in this scenario.

    hep-phastro-ph.COPRD(2016)·7 citations
32. 32*

    Discovery Prospects of a Light Scalar in the NMSSM

    Ulrich Ellwanger🇫🇷 · Matias Rodriguez-Vazquez🇫🇷

    We study a region in the NMSSM parameter space in which the mass of the SM-like Higgs boson is uplifted by ~4-17 GeV, allowing for stop masses and |A_t| <= 1 TeV alleviating the little fine tuning problem of the MSSM. An uplift of the mass of the SM-like Higgs boson is possible in two distinct regions in the NMSSM parameter space: Either for large lambda and small tan(beta) or, through singlet-doublet mixing, for small lambda and large tan(beta). For a mostly singlet-like Higgs state H_S with a mass below 125 GeV we investigate possible direct or indirect search channels at the run II of the LHC as function of the NMSSM-specific uplift of the mass of the SM-like Higgs boson: Direct production of H_S in gluon fusion with H_S decaying into diphotons, modified reduced couplings of the SM-like Higgs state, and the possible production of H_S in ggF -> A -> Z + H_S. We find that the region featuring singlet-doublet mixing can be tested if searches at the LHC at 13 TeV for BSM Higgs bosons in the mass range 88 - 102 GeV decaying into diphotons become sensitive to signal cross sections sigma(gg -> H_S -> diphotons) ~ 20 fb, or if measurements of the reduced coupling kappa_V(H_{SM}) of the SM Higgs boson to electroweak gauge boson exclude (or confirm) the region kappa_V(H_{SM}) <~ 0.93.

    hep-phJHEP(2016)·58 citations
33. 33*

    Prospects for double Higgs production

    Giuliano Panico🇪🇸

    A concise review of the double Higgs production channel at the LHC and at future hadron and lepton machines is presented.

    hep-phFrascati Phys.Ser.(2016)·5 citations
34. 34*

    Top Partners Searches and Composite Higgs Models

    Oleksii Matsedonskyi🇩🇪 · Giuliano Panico🇪🇸 · Andrea Wulzer🇮🇹

    Colored fermionic partners of the top quark are well-known signatures of the Composite Higgs scenario and for this reason they have been and will be subject of an intensive experimental study at the LHC. Performing an assessment of the theoretical implications of this experimental effort is the goal of the present paper. We proceed by analyzing a set of simple benchmark models, characterized by simple two-dimensional parameter spaces where the results of the searches are conveniently visualized and their impact quantified. We only draw exclusion contours, in the hypothesis of no signal, but of course our formalism could equally well be used to report discoveries in a theoretically useful format.

    hep-phJHEP(2016)·63 citations
35. 35*

    The Diboson Excess: Experimental Situation and Classification of Explanations; A Les Houches Pre-Proceeding

    Johann Brehmer🇩🇪 · Gustaaf Brooijmans🇺🇸 · Giacomo Cacciapaglia🇫🇷 · Adrian Carmona🇨🇭 · Sekhar R. Chivukula🇺🇸 · Antonio Delgado🇺🇸 · Florian Goertz🇨🇭 · JoAnne L. Hewett🇺🇸 · Andrey Katz🇨🇭 · Joachim Kopp🇩🇪 · Kenneth Lane🇺🇸 · Adam Martin🇺🇸 and 12 other authors

    We examine the `diboson' excess at $\sim 2$ TeV seen by the LHC experiments in various channels. We provide a comparison of the excess significances as a function of the mass of the tentative resonance and give the signal cross sections needed to explain the excesses. We also present a survey of available theoretical explanations of the resonance, classified in three main approaches. Beyond that, we discuss methods to verify the anomaly, determining the major properties of the various surpluses and exploring how different models can be discriminated. Finally, we give a tabular summary of the numerous explanations, presenting their main phenomenological features.

    hep-ph20 citations
36. 36*

    $\gamma \gamma \to M^{+}{M}^{-}(M=\pi ,K)$ processes with twist-3 corrections in QCD

    Cong Wang🇨🇳 · Ming-Zhen Zhou🇨🇳 · Hong Chen🇨🇳

    We study the $\gamma \gamma \to M^{+}{M}^{-}(M=\pi ,K)$ processes with the contributions from the two-particle twist-2 and twist-3 distribution amplitudes of pion and kaon mesons on BHL prescription in the standard hard-scattering approach. The results show that the contributions from twist-3 parts are actually not power suppressed comparing with the leading-twist contributions and the cross sections agree well with the experimental data in the two-photon center-of-mass energy $W>2.8$ GeV. We also predict the cross section ratio ${\sigma }_0({\pi }^{+}{\pi }^{-})/{\sigma }_0(K^{+}{K}^{-})$, which is compatible with the experimental data from TPC and Belle.

    hep-phEPJC(2017)·4 citations
37. 37*

    Probing the Origin of Neutrino Masses and Mixings via Doubly Charged Scalars: Complementarity of the Intensity and the Energy Frontiers

    Tanja Geib🇩🇪 · Stephen F. King🇬🇧 · Alexander Merle🇩🇪 · Jose Miguel No🇬🇧 · Luca Panizzi🇬🇧

    We discuss how the intensity and the energy frontiers provide complementary constraints within a minimal model of neutrino mass involving just one new field beyond the Standard Model at accessible energy, namely a doubly charged scalar $S^{++}$ and its antiparticle $S^{--}$. In particular we focus on the complementarity between high-energy LHC searches and low-energy probes such as lepton flavor violation. Our setting is a prime example of how high- and low-energy physics can cross-fertilize each other.

    hep-phhep-exPRD(2016)·16 citations
38. 38*

    Composite Higgs models and $t\bar{t}$ production at future $e^{+}{e}^{-}$ colliders

    D. Barducci🇫🇷 · S. De Curtis🇮🇹 · S. Moretti🇬🇧 · G.M. Pruna🇨🇭

    The study of the top quark properties will be an integral part of any particle physics activity at future leptonic colliders. In this proceeding we discuss the possibility of testing composite Higgs scenarios at $e^{+}{e}^{-}$ prototypes through deviations from the Standard Model predictions in $t\bar{t}$ production observables for various centre of mass energies, ranging from 370 GeV up to 1 TeV. This proceedings draws from Ref. arXiv:1504.05407

    hep-phFrascati Phys.Ser.(2016)·0 citations
39. 39*

    Compact Tetraquark Interpretation of the XYZ States

    Angelo Esposito🇺🇸

    The past decade witnessed the observation of several exotic charmonium-like resonances, some of which are manifestly non-qqbar mesons. We review one of the most popular interpretations of such states: the compact tetraquark in the constituent diquark-antidiquark picture. Moreover, we discuss some unexplored decay channels which are particularly sensitive to the different phenomenological models and could therefore shed some light on the nature of these fascinating states. Some brief comments on the recently observed pentaquarks are also included.

    hep-phAIP Conf.Proc.(2016)·0 citations
40. 40*

    BFKL phenomenology

    G. Chachamis🇪🇸

    We present some of the topics covered in a series of lectures under the same title that was given at the "Summer School on High Energy Physics at the LHC: New trends in HEP" in Natal, Brazil. In particular, after some general thoughts on phenomenology we give a pedagogical introduction to the BFKL formalism and we discuss recent BFKL phenomenological studies for LHC observables.

    hep-ph31 citations
41. 41*

    Looking for chiral anomaly in $K\gamma \to K\pi$ reactions

    M. I. Vysotsky🇷🇺 · E. V. Zhemchugov🇷🇺

    In an experiment currently being performed at the Institute for High Energy Physics, Serpukhov, Russia, a beam of charged kaons is directed on a copper target. In the electromagnetic field of the target nuclei, two reactions occur: $K^{+}\gamma \to K^{+}{\pi }^0$ and $K^{+}\gamma \to K^0{\pi }^{+}$. A peculiar distinction between these two reactions is that there is a chiral anomaly contribution in the former reaction, but not in the latter. This contribution can be directly seen through comparison of the cross sections of these reactions near the threshold. We derive expressions for these cross sections taking into account the anomaly and the contribution of the lightest vector mesons.

    hep-phhep-exPRD(2016)·14 citations
42. 42*

    Pion structure function from leading neutron electroproduction and SU(2) flavor asymmetry

    J. R. McKenney🇺🇸 · Nobuo Sato🇺🇸 · W. Melnitchouk🇺🇸 · Chueng-Ryong Ji🇺🇸

    We examine the efficacy of pion exchange models to simultaneously describe leading neutron electroproduction at HERA and the $\bar{d}-\bar{u}$ flavor asymmetry in the proton. A detailed ${\chi }^2$ analysis of the ZEUS and H1 cross sections, when combined with constraints on the pion flux from Drell-Yan data, allows regions of applicability of one-pion exchange to be delineated. The analysis disfavors several models of the pion flux used in the literature, and yields an improved extraction of the pion structure function and its uncertainties at parton momentum fractions in the pion of $4\times 10^{-4}\lesssim x_{\pi }\lesssim 0.05$ at a scale of $Q^2$=10 GeV${}^2$. Based on the fit results, we provide estimates for leading proton structure functions in upcoming tagged deep-inelastic scattering experiments at Jefferson Lab on the deuteron with forward protons.

    hep-phhep-exPRD(2016)·55 citations
43. 43*

    Nucleon Polarizabilities: from Compton Scattering to Hydrogen Atom

    Franziska Hagelstein (JGU Mainz)🇩🇪 · Rory Miskimen (UMass Amherst)🇺🇸 · Vladimir Pascalutsa (JGU Mainz)🇩🇪

    We review the current state of knowledge of the nucleon polarizabilities and of their role in nucleon Compton scattering and in hydrogen spectrum. We discuss the basic concepts, the recent lattice QCD calculations and advances in chiral effective-field theory. On the experimental side, we review the ongoing programs aimed to measure the nucleon (scalar and spin) polarizabilities via the Compton scattering processes, with real and virtual photons. A great part of the review is devoted to the general constraints based on unitarity, causality, discrete and continuous symmetries, which result in model-independent relations involving nucleon polarizabilities. We (re-)derive a variety of such relations and discuss their empirical value. The proton polarizability effects are presently the major sources of uncertainty in the assessment of the muonic hydrogen Lamb shift and hyperfine structure. Recent calculations of these effects are reviewed here in the context of the "proton-radius puzzle". We conclude with summary plots of the recent results and prospects for the near-future work.

    ↳ nucl-thhep-phnucl-exphysics.atom-phPPNP(2016)·111 citations
44. 44*

    Axion Monodromy and the Weak Gravity Conjecture

    Arthur Hebecker🇩🇪 · Fabrizio Rompineve🇩🇪 · Alexander Westphal🇩🇪

    Axions with broken discrete shift symmetry (axion monodromy) have recently played a central role both in the discussion of inflation and the `relaxion' approach to the hierarchy problem. We suggest a very minimalist way to constrain such models by the weak gravity conjecture for domain walls: While the electric side of the conjecture is always satisfied if the cosine-oscillations of the axion potential are sufficiently small, the magnetic side imposes a cutoff, ${\Lambda }^3\sim mf{M}_{pl}$, independent of the height of these `wiggles'. We compare our approach with the recent related proposal by Ibanez, Montero, Uranga and Valenzuela. We also discuss the non-trivial question which version, if any, of the weak gravity conjecture for domain walls should hold. In particular, we show that string compactifications with branes of different dimensions wrapped on different cycles lead to a `geometric weak gravity conjecture' relating volumes of cycles, norms of corresponding forms and the volume of the compact space. Imposing this `geometric conjecture', e.g.~on the basis of the more widely accepted weak gravity conjecture for particles, provides at least some support for the (electric and magnetic) conjecture for domain walls.

    ↳ hep-thastro-ph.COhep-phJHEP(2016)·130 citations
45. 45*

    Non-Abelian twisted kinks in chiral Gross-Neveu model with isospin

    Michael Thies🇩🇪

    The two-dimensional, massless Gross-Neveu model with Nc colors and SU(2) isospin is studied analytically in the large Nc limit. The chiral SU(2)L X SU(2)R symmetry is broken spontaneously in the vacuum. Twisted kinks connecting two arbitrary points on the vacuum manifold S3 are constructed, and their properties are explored. The phase diagram as a function of temperature, baryon- and isospin chemical potential is discussed, with special emphasis on inhomogeneous phases. The preferred form of the condensate is a product of the real kink crystal and the chiral spiral. Kink-kink scattering is solved, using the general solution of the multicomponent Bogoliubov-de Gennes equation recently presented by Takahashi.

    ↳ hep-thhep-lathep-phPRD(2016)·13 citations
46. 46*

    Selected results on hadron structure using state-of-the-art lattice QCD simulations

    Constantia Alexandrou (Univ. of Cyprus & The Cyprus Inst.)🇨🇾

    We review progress on hadron structure using lattice QCD simulations at or near to physical values of the QCD parameters. In particular, we discuss recent results on hadron masses, the nucleon charges, spin, gluon and quark unpolarized moments, the axial charge of hyperons, and the pion unpolarized moment.

    ↳ hep-lathep-phnucl-th8 citations
47. 47*

    Influence of Induced Interactions on Superfluid Properties of Quasi-Two Dimensional Dilute Fermi Gases With Spin-Orbit Coupling

    H. Caldas🇧🇷 · R.L.S. Farias🇧🇷 · M. Continentino🇧🇷

    We study the effects of induced interactions on the pairing gap, transition temperature and chemical potential of a quasi-two dimensional Fermi gas of atoms with spin-orbit coupling. We find that these mean-field parameters are significantly modified when induced interactions are taken into account. We also investigate the implications of induced interactions corrections for the BCS-BEC crossover driven by spin-orbit coupling, that happens even for small (compared to the Fermi energy) values of the binding energy.

    ↳ cond-mat.quant-gascond-mat.otherhep-phPRA(2013)·2 citations
48. 48*

    Novel Topological Effects in Dense QCD in a Magnetic Field

    E.J. Ferrer🇺🇸 · V. de la Incera🇺🇸

    We study the electromagnetic properties of dense QCD in the so-called Magnetic Dual Chiral Density Wave phase. This inhomogeneous phase exhibits a nontrivial topology that comes from the fermion sector due to the asymmetry of the lowest Landau level modes. The nontrivial topology manifests in the electromagnetic effective action via a chiral anomaly term $\theta F^{\mu \nu }{\tilde{F}}_{\mu \nu }$, with a dynamic axion field $\theta$ given by the phase of the dual chiral density wave condensate. The coupling of the axion with the electromagnetic field leads to several macroscopic effects that include, among others, an anomalous, nondissipative Hall current, an anomalous electric charge, magnetoelectricity, and the formation of a hybridized propagating mode known as an axion polariton. Connection to topological insulators and Weyls semimetals, as well as possible implications for heavy-ion collisions and neutron stars are all highlighted.

    ↳ nucl-thcond-mat.mes-hallcond-mat.mtrl-scicond-mat.str-el+1NPB(2018)·38 citations
49. 49*

    Possible relevance of the softening of the sigma meson to $\eta$ decay into 3$\pi$ in the nuclear medium

    Shuntaro Sakai🇯🇵 · Teiji Kunihiro🇯🇵

    We investigate the role of the softening of the scalar-isoscalar (sigma) meson in the $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$ and $3{\pi }^0$ decay widths in the symmetric nuclear medium using a linear sigma model. Our calculation shows that these decay widths in the nuclear medium increase by up to a factor of four to ten compared with those in the free space mainly depending on the mass of the sigma meson in the free space, which is an input parameter of the model. The enhancements are considerable even at a half of the normal nuclear density. Thus, the $\eta$ decay into $3\pi$ could be a possible new probe for the chiral restoration in the nuclear medium. We find that the density dependence of the $\eta \to 3{\pi }^0$ decay is moderate in comparison with that of $\eta \to {\pi }^{+}{\pi }^{-}{\pi }^0$, although the former width is greater than the latter one at a given density. This is because the softening of the sigma meson causes cancellation of the terms appearing from the Bose symmetry in the $\eta \to 3{\pi }^0$ decay. The difference between the density dependences should be helpful for experimental confirmation of the findings of the present study.

    ↳ nucl-thhep-phPTEP(2016)·1 citation
50. 50*

    Boost Breaking in the EFT of Inflation

    Luca V. Delacretaz🇺🇸 · Toshifumi Noumi🇨🇳 · Leonardo Senatore🇺🇸

    If time-translations are spontaneously broken, so are boosts. This symmetry breaking pattern can be non-linearly realized by either just the Goldstone boson of time translations, or by four Goldstone bosons associated with time translations and boosts. In this paper we extend the Effective Field Theory of Multifield Inflation to consider the case in which the additional Goldstone bosons associated with boosts are light and coupled to the Goldstone boson of time translations. The symmetry breaking pattern forces a coupling to curvature so that the mass of the additional Goldstone bosons is predicted to be equal to $\sqrt{2}H$ in the vast majority of the parameter space where they are light. This pattern therefore offers a natural way of generating self-interacting particles with Hubble mass during inflation. After constructing the general effective Lagrangian, we study how these particles mix and interact with the curvature fluctuations, generating potentially detectable non-Gaussian signals.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2017)·24 citations
51. 51*

    Thermalization of parton spectra in the color-flux-tube model

    Radoslaw Ryblewski🇵🇱

    Detailed study of thermalization of the momentum spectra of partons produced via decays of the color flux tubes due to the Schwinger tunneling mechanism is presented. The collisions between particles are included in the relaxation time approximation specified by different values of the shear viscosity to entropy density ratio. At first we show that, to a good approximation, the transverse-momentum spectra of the produced patrons are exponential, irrespectively from the assumed value of the viscosity of the system and the freeze-out time. This thermal-like behaviour may be attributed to specific properties of the Schwinger tunneling process. In the next step, in order to check the approach of the system towards genuine local equilibrium, we compare the local slope of the model transverse-momentum spectra with the local slope of the fully equilibrated reference spectra characterised by the effective temperature that reproduces the energy density of the system. We find that the viscosity corresponding to the AdS/CFT lower bound is necessary for thermalization of the system within about two fermis.

    ↳ nucl-thhep-phJ.Phys.G(2016)·3 citations
52. 52*

    Electromagnetic contribution to charge symmetry violation in parton distributions

    X.G. Wang🇦🇺 · A.W. Thomas🇦🇺 · R.D. Young🇦🇺

    We report a calculation of the combined effect of photon radiation and quark mass differences on charge symmetry violation (CSV) in the parton distribution functions of the nucleon. Following a recent suggestion of Martin and Ryskin, the initial photon distribution is calculated in terms of coherent radiation from the proton as a whole, while the effect of the quark mass difference is based on a recent lattice QCD simulation. The distributions are then evolved to a scale at which they can be compared with experiment by including both QCD and QED radiation. Overall, at a scale of 5 GeV${}^2$, the total CSV effect on the phenomenologically important difference between the $d$ and $u$-quark distributions is some 20\% larger than the value based on quark mass differences alone. In total these sources of CSV account for approximately 40\% of the NuTeV anomaly.

    ↳ nucl-thhep-lathep-phPLB(2016)·5 citations
53. 53*

    The $2\pi$ Subsystem in Diffractively Produced ${\pi }^{-}{\pi }^{+}{\pi }^{-}$ at COMPASS

    Fabian Krinner (for the COMPASS collaboration)🇩🇪

    The COMPASS experiment at CERN has collected a large dataset of $50$ million ${\pi }^{-}{\pi }^{+}{\pi }^{-}$ events produced diffractively from a proton target using a $190\mathrm{GeV}/c$ pion beam. The partial-wave analysis (PWA) of these high-precision data reveals previously unseen details but is limited in parts by systematic effects. The PWA is based on the isobar model, in which multi-particle decays are described as a chain of subsequent two-body decays. Here, fixed mass distributions for the appearing intermediate resonances, the so-called isobars, are assumed. These shapes, which e.g. may be parametrized by Breit-Wigner amplitudes, represent prior knowledge that has to be put into the analysis model and may therefore introduce a model dependence, thus increasing systematic uncertainties. We present a novel method, which allows to extract isobar amplitudes directly from the data in a more model-independent way. As a first application, diffractively produced ${\pi }^{-}{\pi }^{+}{\pi }^{-}$ events are analyzed. Here, the focus lies in particular on the scalar ${\pi }^{+}{\pi }^{-}$ subsystem, where in a previous analysis a signal for a new axial-vector state $a_1(1420)$ was found in the $f_0(980)\pi$ decay mode.

    ↳ hep-exhep-phAIP Conf.Proc.(2016)·0 citations
54. 54*

    Exact solutions, energy and charge of stable Q-balls

    D. Bazeia🇧🇷 · M.A. Marques🇧🇷 · R. Menezes🇧🇷

    In this work we deal with nontopological solutions of the Q-ball type in two spacetime dimensions. We study models of current interest, described by a Higgs-like and other, similar potentials which unveil the presence of exact solutions. We use the analytic results to investigate how to control the energy and charge to make the Q-balls stable.

    ↳ hep-thhep-phEPJC(2016)·36 citations
55. 55*

    Classical Lagrangians and Finsler structures for the nonminimal fermion sector of the Standard-Model Extension

    M. Schreck🇧🇷

    This article is devoted to finding classical point-particle equivalents for the fermion sector of the nonminimal Standard-Model Extension (SME). For a series of nonminimal operators, such Lagrangians are derived at first order in Lorentz violation using the algebraic concept of Gröbner bases. Subsequently, the Lagrangians serve as a basis for reanalyzing the results of certain kinematic tests of Special Relativity that were carried out in the last century. Thereby, a number of new constraints on coefficients of the nonminimal SME is obtained. In the last part of the paper we point out connections to Finsler geometry.

    ↳ hep-thhep-phPRD(2016)·66 citations
56. 56*

    The tau-model of Bose-Einstein Correlations: Some recent results

    W. J. Metzger🇳🇱

    Bose-Einstein correlations of pairs of identical charged pions produced in hadronic Z decays and in 7 TeV pp minimum bias interactions are investigated within the framework of the tau-model.

    ↳ hep-exhep-phEPJ Web Conf.(2016)·2 citations
57. 57*

    Quantum Critical Behaviour of Semi-Simple Gauge Theories

    Jacob Kamuk Esbensen🇩🇰 · Thomas A. Ryttov🇩🇰 · Francesco Sannino🇩🇰

    We study the perturbative phase diagram of semi-simple fermionic gauge theories resembling the Standard Model. We investigate an $SU(N)$ gauge theory with $M$ Dirac flavors where we gauge first an $SU(M{)}_L$ and then an $SU(2{)}_L\subset SU(M{)}_L$ of the original global symmetry $SU(M{)}_L\times SU(M{)}_R\times U(1)$ of the theory. To avoid gauge anomalies we add lepton-like particles. At the two-loops level an intriguing phase diagram appears. We uncover phases in which one, two or three fixed points exist and discuss the associated flows of the coupling constants. We discover a phase featuring complete asymptotic freedom and simultaneously an interacting infrared fixed point in both couplings. The analysis further reveals special renormalisation group trajectories along which one coupling displays asymptotic freedom and the other asymptotic safety, while both flowing in the infrared to an interacting fixed point. These are \emph{safety free} trajectories. We briefly sketch out possible phenomenological implications, among which an independent way to generate near-conformal dynamics a lá walking is investigated.

    ↳ hep-thhep-lathep-phPRD(2016)·35 citations
58. 58*

    Six dimensional QCD at two loops

    J.A. Gracey🇬🇧

    We construct the six dimensional Quantum Chromodynamics (QCD) Lagrangian in a linear covariant gauge and subsequently renormalize it at two loops in the MSbar scheme. The coupling constant corresponding to the gauge interaction is asymptotically free for all numbers of quark fields, Nf. Analysing the beta-functions yields a rich spectrum of fixed points. For instance, the conformal window in the six dimensional theory is at Nf = 16 for the SU(3) colour group. The critical theory structure is similar to that of an O(N) scalar theory in eight dimensions. Using the large N expansion the latter is shown to be in the same universality class as the Heisenberg ferromagnet. Similarly using the large Nf expansion, six dimensional QCD is shown to be in the same class as the two dimensional non-abelian Thirring model and four dimensional QCD. Abelian gauge theories are also renormalized at high loops in six and eight dimensions. It is shown that the gauge parameter only appears in the electron anomalous dimension at one loop, similar to four dimensions.

    ↳ hep-thhep-phPRD(2016)·41 citations
59. 59*

    Multiplicity predictions for Pb-Pb collisions at $\sqrt{s}=5.02$ TeV based on the MC Modified Glauber model

    Andrey Seryakov🇷🇺 · Grigory Feofilov🇷🇺

    We present predictions of the mean multiplicity yields for different centrality classes of Pb-Pb collisions at $\sqrt{s}=5.02$ TeV at the LHC, obtained using the Monte-Carlo Modified Glauber model (MGM) [1]. Contrary to generally used standard Glauber calculations, the MGM takes into account the energy conservation in the soft particles production. The only one efficient model parameter was tuned and fixed previously (k=0.35) by fitting the available data on multiplicity for all colliding systems up to RHIC energies. The MGM has shown already a good predictive capability for the yields at $\sqrt{s}=2.76$ TeV, and it is used again within the same MC code for the calculations at $\sqrt{s}=5.02$ TeV

    ↳ nucl-thhep-phnucl-ex1 citation

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.