Tue·May 3, 2016Tuesday·May 3, 2016

1. 01*

   Flavor-Changing Higgs Decays in Grand Unification with Minimal Flavor Violation

   Seungwon Baek🇰🇷 · Jusak Tandean🇹🇼

   We consider the flavor-changing decays of the Higgs boson in a grand unified theory framework which is based on the SU(5) gauge group and implements the principle of minimal flavor violation. This allows us to explore the possibility of connecting the tentative hint of the Higgs decay $h\to \mu \tau$ recently reported in the CMS experiment to potential new physics in the quark sector. We look at different simple scenarios with minimal flavor violation in this context and how they are subject to various empirical restrictions. In one specific case, the relative strengths of the flavor-changing leptonic Higgs couplings are determined mainly by the known quark mixing parameters and masses, and a branching fraction $\mathcal{B}(h\to \mu \tau )\sim 1\%$ is achievable without the couplings being incompatible with the relevant constraints. Upcoming data on the Higgs leptonic decays and searches for the $\mu \to e\gamma$ decay with improved precision can offer further tests on this scenario.

   hep-phhep-exEPJC(2016)·14 citations
2. 02*

   How well can new particles interacting with neutrinos be constrained after a galactic supernova?

   Jonathan H. Davis🇬🇧

   A supernova event in our own galaxy will result in a large number of neutrinos detected on Earth within the time-frame of a few seconds. These neutrinos will have been produced thermally with, in principle, three distinct temperatures for the electron, anti-electron and remaining heavy flavours respectively. We revisit the possibility that new MeV-mass particles $\chi$ are also produced thermally during the event, which scatter with the neutrinos and alter their temperatures. Our main emphasis is on the detectability of this effect using the neutrino spectrum, given the large uncertainty on the temperature and density profiles of the stellar matter. By marginalising over the parameters of a simple analytic model for the stellar profile, we find that Super Kamiokande could place an upper limit on the scattering cross section at the level of ${\sigma }_{\chi \nu }\sim 10^{-40}\cdot (T/\mathrm{MeV}{)}^2$ cm${}^2$ for 10 MeV mass particles at 90% confidence. A direct-detection-like experiment would be less susceptible to systematic uncertainties in the neutrino production and mixing, but this would need a target mass around 100 tonnes in order to acquire enough statistics to compete with Super Kamiokande.

   hep-phastro-ph.HE4 citations
3. 03*

   The LHC Diphoton excess at 750 GeV in the framework of the Constrained Minimal Supersymmetric Standard Model

   Debajyoti Choudhury🇮🇳 · Kirtiman Ghosh🇮🇳

   We examine the observed diphoton excess at 750 GeV in the framework of constrained Minimal Supersymmetric Standard Model (cMSSM). The consistency of cMSSM with the discovery of a 125 GeV Higgs boson and PLANCK/WMAP data for dark matter relic density (RD) demands large mixing in the scalar top (stop) sector and consequently, the existence of a light stop quasi-degenerate with the lightest neutralino. Small decay width due to kinematic and loop suppression of such a stop allows for the existence of stop-antistop bound states (stoponia). Identifying the particular part of cMSSM parameter space consistent with Higgs boson mass as well as RD, we study stoponia as the source of the diphoton excess.

   hep-ph16 citations
4. 04*

   Exo-Higgs at 750 GeV and Genesis of Baryons

   Hooman Davoudiasl🇺🇸 · Pier Paolo Giardino🇺🇸 · Cen Zhang🇺🇸

   We propose that the diphoton excess at 750 GeV reported by ATLAS and CMS is due to the decay of an $exo-Higgs$ scalar $\eta$ associated with the breaking of a new $SU(2{)}_e$ symmetry, dubbed $exo-spin$. New fermions, $exo-quarks$ and $exo-leptons$, get TeV-scale masses through Yukawa couplings with $\eta$ and generate its couplings to gluons and photons at 1-loop. The matter content of our model yields a $B-L$ anomaly under $SU(2{)}_e$, whose breaking we assume entails a first order phase transition. A non-trivial $B-L$ asymmetry may therefore be generated in the early universe, potentially providing a baryogenesis mechanism through the Standard Model (SM) sphaleron processes. The spontaneous breaking of $SU(2{)}_e$ can in principle directly lead to electroweak symmetry breaking, thereby accounting for the proximity of the mass scales of the SM Higgs and the exo-Higgs. Our model can be distinguished from those comprising a singlet scalar and vector fermions by the discovery of TeV scale exo-vector bosons, corresponding to the broken $SU(2{)}_e$ generators, at the LHC.

   hep-phhep-exPRD(2016)·12 citations
5. 05*

   EW scale DM models with dark gauge symmetries

   P. Ko🇰🇷

   In this talk, I describe a class of electroweak (EW) scale dark matter (DM) models where its stability or longevity are the results of underlying dark gauge symmetries: stable due to unbroken local dark gauge symmetry or topology, or long-lived due to the accidental global symmetry of dark gauge theories. Compared with the usual phenomenological dark matter models (including DM EFT or simplified DM models), DM models with local dark gauge symmetries include dark gauge bosons, dark Higgs bosons and sometimes excited dark matter. And dynamics among these fields are completely fixed by local gauge principle. The idea of singlet portals including the Higgs portal can thermalize these hidden sector dark matter very efficiently, so that these DM could be easily thermal DM. I also discuss the limitation of the usual DM effective field theory or simplified DM models without the full SM gauge symmetry, and emphasize the importance of the full SM gauge symmetry and renormalizability especially for collider searches for DM.

   hep-phPoS(2016)·1 citation
6. 06*

   Long Range Correlation in Higgs Boson Plus Two Jets Production at the LHC

   Peng Sun🇺🇸 · C.-P. Yuan🇺🇸 · Feng Yuan🇺🇸

   We study Higgs boson plus two high energy jets production at the LHC in the kinematics where the two jets are well separated in rapidity. The partonic processes are dominated by the t-channel weak boson fusion (WBF) and gluon fusion (GF) contributions. We derive the associated QCD resummation formalism for the correlation analysis where the total transverse momentum q_\perp of the Higgs boson and two jets is small. Because of different color structures, the resummation results lead to distinguished behaviors: the WBF contribution peaks at relative low q_\perp while all GF channel contributions are strongly de-correlated and spread to a much wider q_\perp range. By applying a kinematic cut on q_\perp, one can effectively increase the WBF signal to the GF background by a significant factor. This greatly strengthens the ability to investigate the WBF channel in Higgs boson production and study the couplings of Higgs to electroweak bosons.

   hep-phhep-exPLB(2016)·8 citations
7. 07*

   Comprehensive Analysis of Yukawa Hierarchies on $T^2/Z_N$ with Magnetic Fluxes

   Yukihiro Fujimoto🇯🇵 · Tatsuo Kobayashi🇯🇵 · Kenji Nishiwaki🇰🇷 · Makoto Sakamoto🇯🇵 · Yoshiyuki Tatsuta🇯🇵

   Based on the result of classification in our previous work, we exhaustively investigate Yukawa sector of $U(8)$ model on magnetized orbifolds $T^2/Z_2$, $T^2/Z_3$, $T^2/Z_4$ and $T^2/Z_6$ by evaluating ratios of the mass eigenvalues of the three states in all the possible configurations with one and two Higgs pairs where three generations are realized in fermions. Because of smearing effect via kinetic mixing, one can realize a hierarchy such as $10^{-2}$-$10^{-3}$, but it is very difficult to achieve the mass ratio between the up and top quarks ($m_{\text{up}}/m_{\text{top}}\sim 10^{-5}$) on the complicated magnetized orbifolds $T^2/Z_N(N=3,4,6)$.

   hep-phPRD(2016)·50 citations
8. 08*

   The slope, curvature, and higher parameters in $pp$ and $\bar{p}p$ scattering, and the extrapolation of measurements of $d\sigma (s,t)/dt$ to $t=0$

   Martin M. Block🇺🇸 · Loyal Durand🇺🇸 · Phuoc Ha🇺🇸 · Francis Halzen🇺🇸

   We study the effects of curvature in the expansion of the logarithm of the differential elastic scattering cross section near $t=0$ as $d\sigma (s,t)/dt=d\sigma (s,0)/dt\times \exp (Bt+C{t}^2+D{t}^3\cdots )$ in an eikonal model for $pp$ and $\bar{p}p$ scattering, and use the results to discuss the extrapolation of measured differential cross sections and the slope parameters $B$ to $t=-q^2=0$. We find that the curvature effects represented by the parameters $C$ and $D$, while small, lead to significant changes in the forward slope parameter relative to that determined in a purely exponential fit, and to smaller but still significant changes in the forward elastic scattering and total cross sections. Curvature effects should therefore be considered in future analyses or reanalyses of the elastic scattering data.

   hep-phPRD(2016)·8 citations
9. 09*

   Jet quenching parameter of quark-gluon plasma in strong magnetic field: Perturbative QCD and AdS/CFT correspondence

   Shiyong Li🇺🇸 · Kiminad A. Mamo🇺🇸 · Ho-Ung Yee🇺🇸

   We compute the jet quenching parameter $\hat{q}$ of QCD plasma in the presence of strong magnetic field in both weakly and strongly coupled regimes. In weakly coupled regime, we compute $\hat{q}$ in perturbative QCD at complete leading order (that is, leading log as well as the constant under the log) in QCD coupling constant ${\alpha }_s$, assuming the hierarchy of scales ${\alpha }_{s}eB\ll T^2\ll eB$. We consider two cases of jet orientations with respect to the magnetic field: 1) the case of jet moving parallel to the magnetic field, 2) the case jet moving perpendicular to the magnetic field. In the former case, we find $\hat{q}\sim {\alpha }_s^2(eB)T\log (1/{\alpha }_s)$, while in the latter we have $\hat{q}\sim {\alpha }_s^2(eB)T\log (T^2/{\alpha }_{s}eB)$. In both cases, this leading order result arises from the scatterings with thermally populated lowest Landau level quarks. In strongly coupled regime described by AdS/CFT correspondence, we find $\hat{q}\sim \sqrt{\lambda }(eB)T$ or $\hat{q}\sim \sqrt{\lambda }\sqrt{eB}{T}^2$ in the same hierarchy of $T^2\ll eB$ depending on whether the jet is moving parallel or perpendicular to the magnetic field, respectively, which indicates a universal dependence of $\hat{q}$ on $(eB)T$ in both regimes for the parallel case, the origin of which should be the transverse density of lowest Landau level states proportional to $eB$. Finally, the asymmetric transverse momentum diffusion in the case of jet moving perpendicular to the magnetic field may give an interesting azimuthal asymmetry of the gluon Bremsstrahlung spectrum in the BDMPS-Z formalism.

   hep-phhep-thnucl-exnucl-thPRD(2016)·51 citations
10. 10*

    On uplimit of accurate measurement of tau mass

    X.H. Mo🇨🇳

    Tau lepton as one of three elementary leptons in nature, the measurement of its mass has ever been performed since its discovery. The present relative accuracy is already at the level of better than 10 to minus 4 and more effects are still made in order to increase the accuracy further. However, the analysis of available techniques for and expectable luminosity from e+e- collider indicates that the precision uplimit of tau mass is almost reached, which means that brand new approaches should be looked for if the great improvement is yearned for.

    hep-phMod.Phys.Lett.A(2016)·2 citations
11. 11*

    Precise determination of the low-energy hadronic contribution to the muon $g-2$ from analyticity and unitarity: An improved analysis

    B.Ananthanarayan🇮🇳 · Irinel Caprini🇷🇴 · Diganta Das🇮🇳 · I. Sentitemsu Imsong🇮🇳

    The two-pion low-energy contribution to the anomalous magnetic moment of the muon, $a_{\mu }\equiv (g-2{)}_{\mu }/2$, expres sed as an integral over the modulus squared of the pion electromagnetic form fac tor, brings a relatively large contribution to the theoretical error, since the low accuracy of experimental measurements in this region is amplified by the drastic increase of the integration kernel. We derive stringent constraints on the two-pion contribution by exploiting analyticity and unitarity of the pion electromagnetic form factor. To avoid the poor knowledge of the modulus of this function, we use instead its phase, known with high precision in the elastic region from Roy equations for pion-pion scattering via the Fermi-Watson theorem. Above the inelastic threshold we adopt a conservative integral condition on the modulus, determined from data and perturbative QCD. Additional high precision data on the modulus in the range $0.65-0.71$ GeV, obtained from $e^{+}{e}^{-}$ annihilation and $\tau$-decay experiments, are used to improve the predictions on the modulus at lower energies by means of a parametrization-free analytic extrapolation. The results are optimal for a given input and do not depend on the unknown phase of the form factor above the inelastic threshold. The present work improves a previous analysis based on the same technique, including more experimental data and employing better statistical tools for their treatment. We obtain for the contribution to $a_{\mu }$ from below 0.63 GeV the value $(133.258\pm 0.723)\times 10^{-10}$, which amounts to a reduction of the theoretical error by about $6\times 10^{-11}$.

    hep-phhep-exPRD(2016)·33 citations
12. 12*

    750 GeV diphoton resonance and electric dipole moments

    Kiwoon Choi🇰🇷 · Sang Hui Im🇰🇷 · Hyungjin Kim🇰🇷 · Doh Young Mo🇰🇷

    We examine the implication of the recently observed 750 GeV diphoton excess for the electric dipole moments of the neutron and electron. If the excess is due to a spin zero resonance which couples to photons and gluons through the loops of massive vector-like fermions, the resulting neutron electric dipole moment can be comparable to the present experimental bound if the CP-violating angle {\alpha} in the underlying new physics is of O(10^{-1}). An electron EDM comparable to the present bound can be achieved through a mixing between the 750 GeV resonance and the Standard Model Higgs boson, if the mixing angle itself for an approximately pseudoscalar resonance, or the mixing angle times the CP-violating angle {\alpha} for an approximately scalar resonance, is of O(10^{-3}). For the case that the 750 GeV resonance corresponds to a composite pseudo-Nambu-Goldstone boson formed by a QCD-like hypercolor dynamics confining at \Lambda_HC, the resulting neutron EDM can be estimated with \alpha ~ (750 GeV / \Lambda_HC)^2\theta_HC, where \theta_HC is the hypercolor vacuum angle.

    hep-phPLB(2016)·19 citations
13. 13*

    Global $U(1{)}_L$ Breaking in Neutrinophilic 2HDM: From LHC Signatures to X-Ray Line

    Weijian Wang🇨🇳 · Zhi-Long Han🇨🇳

    Lepton number violation plays an essential role in many scenarios of neutrino mass generation and also provides new clues to search new physics beyond the standard model. We consider the neutrinophilic two-Higgs-doublet model ($\nu$-2HDM) where additional right-handed neutral fermions $N_{Ri}$ and a complex singlet scalar $\sigma$ are also involved. In scalar sector, the global $U(1{)}_L$ symmetry is spontaneous broken, leading to Nambu-Goldstone boson, the Majoron $J$, accompanied by the Majorana neutrino mass generation. We find that the massless Majoron will induce large invisible Higgs decay, and current experiments have already set constraints on relevant parameters. For the first time, we point out that the $\nu$-2HDM with $N_{Ri}$ can be distinguished from other seesaw by the same sign tri-lepton signature $3{\ell }^{\pm }4j+{\cancel{E}}_T$. More interesting, for $\mathcal{O}(\text{keV})$ scale Majoron, it is a good candidate of decaying dark matter to interpret the $3.5\text{keV}$ and $511\text{keV}$ line excesses.

    hep-phPRD(2016)·29 citations
14. 14*

    Do Neutrino Wave Functions Overlap and Does it Matter?

    Cheng-Hsien Li🇺🇸 · Yong-Zhong Qian🇺🇸

    Studies of neutrinos commonly ignore anti-symmetrization of their wave functions. This implicitly assumes that either spatial wave functions for neutrinos with approximately the same momentum do not overlap or their overlapping has no measurable consequences. We examine these assumptions by considering the evolution of three-dimensional neutrino wave packets (WPs). We find that it is perfectly adequate to treat accelerator and reactor neutrinos as separate WPs for typical experimental setup. While solar and supernova neutrinos correspond to overlapping WPs, they can be treated effectively as non-overlapping for analyses of their detection.

    hep-ph2 citations
15. 15*

    Curvature-Restored Gauge Invariance and Ultraviolet Naturalness

    Durmus Ali Demir🇹🇷

    It is shown that, $(a{\Lambda }^2+b|H{|}^2)R$ in a spacetime of curvature $R$ is a natural ultraviolet $(UV)$ completion of $(a{\Lambda }^4+b{\Lambda }^2|H{|}^2)$ in the flat-spacetime Standard Model $(SM)$ with Higgs field $H$, $UV$ scale $\Lambda$ and loop factors $a$, $b$. This curvature completion rests on the fact that a $\Lambda$-mass gauge theory in flat spacetime turns, on the cut-view $R=4{\Lambda }^2$, into a massless gauge theory in curved spacetime. It provides a symmetry reason for curved spacetime, wherein gravity and matter are both low-energy effective phenomena. Gravity arises correctly if new physics exists with at least 63 more bosons than fermions, with no need to interact with the $SM$ and with dark matter as a natural harbinger. It can source various cosmological, astrophysical and collider phenomena depending on its spectrum and couplings to the $SM$.

    hep-phastro-ph.COgr-qchep-thAdv.High Energy Phys.(2016)·33 citations
16. 16*

    Flavour Physics and CP Violation

    Y. Nir (Weizmann Inst.)🇮🇱

    We explain the many reasons for the interest in flavor physics. We describe flavor physics and the related CP violation within the Standard Model, and explain how the B-factories proved that the Kobayashi-Maskawa mechanism dominates the CP violation that is observed in meson decays. We explain the implications of flavor physics for new physics, with emphasis on the "new physics flavor puzzle", and present the idea of minimal flavor violation as a possible solution. We explain why the values flavor parameters of the Standard Model are puzzling, present the Froggatt-Nielsen mechanism as a possible solution, and describe how measurements of neutrino parameters are interpreted in the context of this puzzle. We show that the recently discovered Higgslike boson may provide new opportunities for making progress on the various flavor puzzles.

    hep-phCERN-2015-001, pp.123-156·21 citations
17. 17*

    Classical conformality in the Standard Model from Coleman's theory

    Kiyoharu Kawana🇯🇵

    The classical conformality is one of the possible candidates for explaining the gauge hierarchy of the Standard Model. We show that it is naturally obtained from the Coleman's theory on baby universe.

    hep-phhep-thMod.Phys.Lett.A(2016)·4 citations
18. 18*

    Towards extracting the best possible results from NOvA

    C. Soumya · R. Mohanta🇮🇳

    The NuMI Off-Axis ${\nu }_e$ Appearance (NO$\nu$A) is the currently running leading long-baseline neutrino oscillation experiment, whose main physics goal is to explore the current issues in the neutrino sector, such as determination of the neutrino mass ordering, resolution of the octant of atmospheric mixing angle and to constrain the Dirac-type CP violating phase ${\delta }_{CP}$. In this paper, we would like to investigate whether it is possible to extract the best possible results from NO$\nu$A with a shorter time-span than its scheduled run period by analyzing its capability to discriminate the degeneracy among various neutrino oscillation parameters within four years of run time, with two years in each neutrino and antineutrino modes. Further, we study the same by adding the data from T2K experiment for a total of five years run with 3.5 years in neutrino mode and 1.5 years in antineutrino mode. We find that NO$\nu$A (2+2) has a better oscillation parameter degeneracy discrimination capability compared to its scheduled run period for four years, i.e, NO$\nu$A (3+1).

    hep-phEPJC(2016)·6 citations
19. 19*

    Interference Effects in the Decays of Spin-Zero Resonances into $\gamma \gamma$ and $t\bar{t}$

    Abdelhak Djouadi🇫🇷 · John Ellis🇬🇧 · Jérémie Quevillon🇬🇧

    We consider interference effects in the production via gluon fusion in LHC collisions at 13 TeV and decays into $\gamma \gamma$ and $t\bar{t}$ final states of one or two putative new resonant states $\Phi$, assumed here to be scalar and/or pseudo scalar particles. Although our approach is general, we use for our numerical analysis the example of the putative $750$ GeV state for which a slight excess was observed in the initial LHC $13$ TeV data. We revisit previous calculations of the interferences between the heavy-fermion loop-induced $gg\to \Phi \to \gamma \gamma$ signal and the continuum $gg\to \gamma \gamma$ QCD background, which can alter the production rate as well as modify the line-shape and apparent mass. We find a modest enhancement by $\sim 20$% under favorable circumstances, for a large $\Phi$ width. The effect of interference on the apparent scalar-pseudoscalar mass difference in a two-Higgs-doublet model is found to be also modest. An exploratory study indicates that similar effects are to be expected in the $gg\to \Phi \to Z\gamma$ channel. In this and other models with a large $\Phi$ total width, the dominant $\Phi$ decays are expected to be into $t\bar{t}$ final states. We therefore also study the effects of interference of the $gg\to \Phi \to t\bar{t}$ signal with the $gg\to t\bar{t}$ continuum QCD background and show that in the presence of standard fermions only in the $gg\to \Phi$ loops, it is destructive causing a dip in the $t\bar{t}$ mass distribution. Including additional vector-like quarks leads to a different picture as peaks followed by dips can then occur. We use the absence of such effects in ATLAS and CMS data to constrain models of the production and decays of the $\Phi$ state(s).

    hep-phhep-exJHEP(2016)·48 citations
20. 20*

    NLO QCD and electroweak corrections to $WWW$ production at the LHC

    Shen Yong-Bai🇨🇳 · Zhang Ren-You🇨🇳 · Ma Wen-Gan🇨🇳 · Li Xiao-Zhou🇨🇳 · Guo Lei🇨🇳

    In this paper we calculate the next-to-leading order (NLO) QCD $[\mathcal{O}({\alpha }_s{\alpha }^3)]$ and electroweak (EW) $[\mathcal{O}({\alpha }^4)]$ corrections to the $WWW$ production at the LHC and deal with the subsequent leptonic decays from $W$ bosons by adopting an improved narrow-width approximation which takes into account the spin correlation and finite-width effects. The NLO QCD correction from the real jet radiation is discussed, which significantly enhances the production rate, particularly in the high-energy region. We also provide the integrated cross section for the $WWW$ production and various kinematic distributions of final products at the QCD+EW NLO. We find that the convergence of the perturbative QCD description can be improved by applying a hard jet veto in the event selection, but this jet veto would introduce a new source of theoretical uncertainty. The pure NLO QCD relative correction to the integrated cross section for the $W^{+}{W}^{-}{W}^{+}$ production at the $14\mathrm{TeV}$ LHC is on the order of $30\%$ in the jet-veto event selection scheme with $p_{T,\mathrm{jet}}^{\mathrm{cut}}=50\mathrm{GeV}$, while the genuine NLO EW relative correction can reach about $15\%$ in the inclusive event selection scheme. Our numerical results show that both the NLO QCD and NLO EW corrections should be taken into consideration in precision predictions.

    hep-phPRD(2017)·31 citations
21. 21*

    Lorentz invariant relative velocity and relativistic binary collisions

    Mirco Cannoni🇪🇸

    This article reviews the concept of Lorentz invariant relative velocity that is often misunderstood or unknown in high energy physics literature. The properties of the relative velocity allow to formulate the invariant flux and cross section without recurring to non--physical velocities or any assumption about the reference frame. Applications such as the luminosity of a collider, the use as kinematic variable, and the statistical theory of collisions in a relativistic classical gas are reviewed. It is emphasized how the hyperbolic properties of the velocity space explain the peculiarities of relativistic scattering.

    hep-phastro-ph.COhep-exhep-thInt.J.Mod.Phys.A(2017)·28 citations
22. 22*

    Effective Field Theories for the LHC

    Ian Moult🇺🇸

    In this thesis I study applications of effective field theories to understand aspects of QCD jets and their substructure at the Large Hadron Collider. In particular, I introduce an observable, $D_2$, which can be used for distinguishing boosted $W/Z/H$ bosons from the QCD background using information about the radiation pattern within the jet, and perform a precision calculation of this observable. To simplify calculations in the soft collinear effective theory, I also develop a helicity operator basis, which facilitates matching calculations to fixed order computations performed using spinor-helicity techniques, and demonstrate its utility by computing an observable relevant for studying the properties of the newly discovered Higgs boson.

    hep-ph1 citation
23. 23*

    Flipped versions of the universal 3-3-1 and the left-right symmetric models in $[SU(3){]}^3$: a comprehensive approach

    Oscar Rodríguez🇨🇴 · Richard H. Benavides🇨🇴 · William A. Ponce🇨🇴 · Eduardo Rojas🇨🇴

    By considering the 3-3-1 and the left-right symmetric models as low energy effective theories of the $SU(3{)}_C\otimes SU(3{)}_L\otimes SU(3{)}_R$~(for short $[SU(3){]}^3$) gauge group, alternative versions of these models are found. The new neutral gauge bosons of the universal 3-3-1 model and its flipped versions are presented; also, the left-right symmetric model and its flipped variants are studied. Our analysis shows that there are two flipped versions of the universal 3-3-1 model, with the particularity that both of them have the same weak charges. For the left-right symmetric model we also found two flipped versions; one of them new in the literature which, unlike those of the 3-3-1, requires a dedicated study of its electroweak properties. For all the models analyzed, the couplings of the $Z^{\prime }$ bosons to the standard model fermions are reported. The explicit form of the null space of the vector boson mass matrix for an arbitrary Higgs tensor and gauge group is also presented. In the general framework of the $[SU(3){]}^3$ gauge group, and by using the LHC experimental results and EW precision data, limits on the $Z^{\prime }$ mass and the mixing angle between $Z$ and the new gauge bosons $Z^{\prime }$ are obtained. The general results call for very small mixing angles in the range $10^{-3}$ radians and $M_{Z^{\prime }}>$ 2.5 TeV.

    hep-phPRD(2017)·10 citations
24. 24*

    Probing gaugino coannihilation with displaced vertex searches

    Natsumi Nagata🇺🇸

    Bino-like dark matter in supersymmetric theories tends to suffer from over-production. This problem can be evaded if there is another gaugino which has a mass close to the bino mass so that it enhances the annihilation rate of bino dark matter through coannihilation. We study such possibilities in high-scale supersymmetric models, and show that searches for long-lived particles with displaced vertices can test the bino-gaugino coannihilation scenario in the forthcoming LHC experiments.

    hep-phPoS(2016)·1 citation
25. 25*

    Gauge coupling unification with extra Higgs doublets

    Junpei Harada🇯🇵

    Gauge coupling unification is studied within the framework where there are extra Higgs doublets and $E_6$ exotic fields. Supersymmetric models and nonsupersymmetric models are investigated, and a catalog of models with gauge coupling unification is presented.

    hep-phFortsch.Phys.(2016)·3 citations
26. 26*

    Beam energy dependence of pseudorapidity distributions of charged particles produced in heavy-ion collisions at RHIC and LHC energies

    Sumit Basu🇮🇳 · Tapan K. Nayak🇮🇳 · Kaustuv Datta🇺🇸

    Heavy-ion collisions at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory and the Large Hadron Collider at CERN probe matter at extreme conditions of temperature and energy density. Most of the global properties of the collisions can be extracted from the measurements of charged particle multiplicity and pseudorapidity ($\eta$) distributions. We have shown that the available experimental data on beam energy and centrality dependence of \Eta-distributions in heavy-ion (Au+Au or Pb+Pb) collisions from \sNN=7.7 GeV to 2.76 TeV are reasonably well described by the AMPT model, which is used for further exploration. The nature of the \Eta-distributions has been described by a double Gaussian function using a set of fit parameters, which exhibit a regular pattern as a function of beam energy. By extrapolating the parameters to a higher energy of \sNN~=~5.02 TeV, we have obtained the charged particle multiplicity densities, \Eta-distributions and energy densities for various centralities. Incidentally, these results match well with some of the recently published data by the ALICE collaboration.

    ↳ nucl-exhep-exhep-phPRC(2016)·16 citations
27. 27*

    Early Time Dynamics of Gluon Fields in High Energy Nuclear Collisions

    Joseph I. Kapusta🇺🇸 · Guangyao Chen🇺🇸 · Rainer J. Fries🇺🇸 · Yang Li🇺🇸

    Nuclei colliding at very high energy create a strong, quasi-classical gluon field during the initial phase of their interaction. We present an analytic calculation of the initial space-time evolution of this field in the limit of very high energies using a formal recursive solution of the Yang-Mills equations. We provide analytic expressions for the initial chromo-electric and chromo-magnetic fields and for their energy-momentum tensor. In particular, we discuss event-averaged results for energy density and energy flow as well as for longitudinal and transverse pressure of this system. Our results are generally applicable if $\tau <1/Q_s$. The transverse energy flow of the gluon field exhibits hydrodynamic-like contributions that follow transverse gradients of the energy density. In addition, a rapidity-odd energy flow also emerges from the non-abelian analog of Gauss' Law and generates non-vanishing angular momentum of the field. We will discuss the space-time picture that emerges from our analysis and its implications for observables in heavy ion collisions.

    ↳ nucl-thhep-phNPA(2016)·2 citations
28. 28*

    Lensing of Fast Radio Bursts as a Probe of Compact Dark Matter

    Julian B. Muñoz🇺🇸 · Ely D. Kovetz🇺🇸 · Liang Dai🇺🇸 · Marc Kamionkowski🇺🇸

    The possibility that part of the dark matter is made of massive compact halo objects (MACHOs) remains poorly constrained over a wide range of masses, and especially in the $20-100M_{\odot }$ window. We show that strong gravitational lensing of extragalactic fast radio bursts (FRBs) by MACHOs of masses larger than $\sim 20M_{\odot }$ would result in repeated FRBs with an observable time delay. Strong lensing of an FRB by a lens of mass $M_L$ induces two images, separated by a typical time delay $\sim$ few $\times (M_L/30M_{\odot })$ milliseconds. Considering the expected FRB detection rate by upcoming experiments, such as CHIME, of $10^4$ FRBs per year, we should observe from tens to hundreds of repeated bursts yearly, if MACHOs in this window make up all the dark matter. A null search for echoes with just $10^4$ FRBs, would constrain the fraction $f_{\mathrm{DM}}$ of dark matter in MACHOs to $f_{\mathrm{DM}}\lesssim 0.08$ for $M_L\gtrsim 20M_{\odot }$.

    ↳ astro-ph.COastro-ph.HEhep-phPRL(2016)·237 citations
29. 29*

    BCFW-type recurrent relations for tree amplitudes of D=11 supergravity

    Igor Bandos🇪🇸

    We propose the on-shell superfield description for tree amplitudes of D=11 supergravity and the BCFW (Britto-Cachazo-Feng-Witten)-type recurrent relations for these superamplitudes.

    ↳ hep-thgr-qchep-phPRL(2017)·14 citations
30. 30*

    Charged Current Coherent Pion Production in Neutrino Scattering

    Paul Martins🇬🇧

    We summarise here the main differences of three models of neutrino-induced coherent pion production, namely the Rein-Sehgal and Berger-Sehgal models based on the Partially Conserved Axial Current theorem and the Alvarez-Ruso \textit{et al.} model which is using a microscopic approach. Their predictions in the event generators are compared against recent experimental measurements for a neutrino energy from 0.5 to 20 GeV.

    ↳ hep-exhep-ph5 citations
31. 31*

    Study the effect of beam energy spread and detector resolution on the search for Higgs boson decays to invisible particles at a future e${}^{+}$e${}^{-}$ circular collider

    Olmo Cerri🇮🇹 · Michele de Gruttola🇨🇭 · Maurizio Pierini🇨🇭 · Alessandro Podo🇮🇹 · Gigi Rolandi🇨🇭

    We study the expected sensitivity to measure the branching ratio of Higgs boson decays to invisible particles at a future circular \epem collider (FCC-ee) in the process $e^{+}{e}^{-}\to HZ$ with $Z\to {\ell }^{+}{\ell }^{-}$ ($\ell =e$ or $\mu$) using an integrated luminosity of 3.5 ab${}^{-1}$ at a center-of-mass energy $\sqrt{s}=240$ GeV. The impact of the energy spread of the FCC-ee beam and of the resolution in the reconstruction of the leptons is discussed. %Two different detector concepts are considered: a detector corresponding to the CMS reconstruction performances and the expected design of the ILC detector. The minimum branching ratio for a $5\sigma$ observation after 3.5ab${}^{-1}$ of data taking is $1.7\pm 0.1\%(stat+syst)$. The branching ratio exclusion limit at 95\% CL is $0.63\pm 0.22\%((stat+syst))$.

    ↳ hep-exhep-phEPJC(2017)·17 citations
32. 32*

    Electric dipole moment of the deuteron in the standard model with $NN-\Lambda N-\Sigma N$ coupling

    Nodoka Yamanaka

    We calculate the electric dipole moment (EDM) of the deuteron in the standard model with $|\Delta S|=1$ interactions by taking into account the $NN-\Lambda N-\Sigma N$ channel coupling, which is an important nuclear level systematics. The two-body problem is solved with the Gaussian Expansion Method using the realistic Argonne $v18$ nuclear force and the $YN$ potential which can reproduce the binding energies of ${}_{\Lambda }^3$H, ${}_{\Lambda }^3$He, and ${}_{\Lambda }^4$He. The $|\Delta S|=1$ interbaryon potential is modeled by the one-meson exchange process. It is found that the deuteron EDM is modified by less than 10\%, and the main contribution to this deviation is due to the polarization of the hyperon-nucleon channels. The effect of the $YN$ interaction is small, and treating $\Lambda N$ and $\Sigma N$ channels as free is a good approximation for the EDM of the deuteron.

    ↳ nucl-thhep-exhep-phnucl-exNPA(2017)·27 citations
33. 33*

    Solving the missing GRB neutrino and GRB-SN puzzles

    Daniele Fargion🇮🇹 · Pietro Oliva🇮🇹

    Every GRB model where the progenitor is assumed to be a highly relativistic hadronic jet whose pions, muons and electron pair secondaries are feeding the gamma jets engine, necessarily (except for very fine-tuned cases) leads to a high average neutrino over photon radiant exposure (radiance), a ratio well above unity, though the present observed average IceCube neutrino radiance is at most comparable to the gamma in the GRB one. Therefore no hadronic GRB, fireball or hadronic thin precessing jet, escaping exploding star in tunneled or penetrarting beam, can fit the actual observations. A new model is shown here, based on a purely electronic progenitor jet, fed by neutrons (and relics) stripped from a neutron star (NS) by tidal forces of a black hole or NS companion, showering into a gamma jet. Such thin precessing spinning jets explain unsolved puzzles such as the existence of the X-ray precursor in many GRBs. The present pure electron jet model, disentangling gamma and (absent) neutrinos, explains naturally why there is no gamma GRB correlates with any simultaneous TeV IceCube astrophysical neutrinos. Rare unstable NS companion stages while feeding the jet may lead to an explosion simulating a SN event. Recent IceCube-160731A highest energy muon neutrino event with absent X-gamma traces confirms the present model expectations.

    ↳ astro-ph.HEastro-ph.COgr-qchep-phNucl.Part.Phys.Proc.(2018)·8 citations
34. 34*

    Running the running

    Giovanni Cabass🇮🇹 · Eleonora Di Valentino🇫🇷 · Alessandro Melchiorri🇮🇹 · Enrico Pajer🇳🇱 · Joseph Silk🇫🇷

    We use the recent observations of Cosmic Microwave Background temperature and polarization anisotropies provided by the Planck satellite experiment to place constraints on the running ${\alpha }_{\mathrm{s}}=\mathrm{d}{n}_{\mathrm{s}}/\mathrm{d}\log k$ and the running of the running ${\beta }_{\mathrm{s}}=\mathrm{d}{\alpha }_{\mathrm{s}}/\mathrm{d}\log k$ of the spectral index $n_{\mathrm{s}}$ of primordial scalar fluctuations. We find ${\alpha }_{\mathrm{s}}=0.011\pm 0.010$ and ${\beta }_{\mathrm{s}}=0.027\pm 0.013$ at $68\%\mathrm{CL}$, suggesting the presence of a running of the running at the level of two standard deviations. We find no significant correlation between ${\beta }_{\mathrm{s}}$ and foregrounds parameters, with the exception of the point sources amplitude at $143\mathrm{GHz}$, $A_{143}^{PS}$, which shifts by half sigma when the running of the running is considered. We further study the cosmological implications of such preference for ${\alpha }_{\mathrm{s}},{\beta }_{\mathrm{s}}\sim 0.01$ by including in the analysis the lensing amplitude $A_L$, the curvature parameter ${\Omega }_k$, and the sum of neutrino masses $\sum m_{\nu }$. We find that when the running of the running is considered, Planck data are more compatible with the standard expectations of $A_L=1$ and ${\Omega }_k=0$ but still hint at possible deviations. The indication for ${\beta }_{\mathrm{s}}>0$ survives at two standard deviations when external datasets such as BAO and CFHTLenS are included in the analysis, and persists at $\sim 1.7$ standard deviations when CMB lensing is considered. We discuss the possibility of constraining ${\beta }_{\mathrm{s}}$ with current and future measurements of CMB spectral distortions, showing that an experiment like PIXIE could provide strong constraints on ${\alpha }_{\mathrm{s}}$ and ${\beta }_{\mathrm{s}}$.

    ↳ astro-ph.COhep-phPRD(2016)·58 citations
35. 35*

    Isospin decomposition of $\gamma N\to N^{\ast }$ transitions within a dynamical coupled-channels model

    H. Kamano🇯🇵 · S. X. Nakamura🇯🇵 · T.-S. H. Lee🇺🇸 · T. Sato🇯🇵

    By extending the dynamical coupled-channels analysis performed in our previous work [Phys. Rev. C 88, 035209 (2013)] to include the available data of photoproduction of pi meson off the neutron, the transition amplitudes for the photo-excitation of the neutron to nucleon resonances, gamma n --> N*, at the resonance pole positions are determined. The combined fits to the data for both the proton- and neutron-target reactions also revise our results for the resonance pole positions and the gamma p --> N* transition amplitudes. Our results allow an isospin decomposition of the gamma N --> N* transition amplitudes for the isospin I=1/2 N* resonances, which is necessary for testing hadron structure models and gives crucial inputs for constructing models of neutrino-induced reactions in the nucleon resonance region.

    ↳ nucl-thhep-phPRC(2016)·77 citations
36. 36*

    Accessing proton generalized parton distributions and pion distribution amplitudes with the exclusive pion-induced Drell-Yan process at J-PARC

    Takahiro Sawada🇹🇼 · Wen-Chen Chang🇹🇼 · Shunzo Kumano🇯🇵 · Jen-Chieh Peng🇺🇸 · Shinya Sawada🇯🇵 · Kazuhiro Tanaka🇯🇵

    Generalized parton distributions (GPDs) encoding multidimensional information of hadron partonic structure appear as the building blocks in a factorized description of hard exclusive reactions. The nucleon GPDs have been accessed by deeply virtual Compton scattering and deeply virtual meson production with lepton beam. A complementary probe with hadron beam is the exclusive pion-induced Drell-Yan process. In this paper, we discuss recent theoretical advances on describing this process in terms of nucleon GPDs and pion distribution amplitudes. Furthermore, we address the feasibility of measuring the exclusive pion-induced Drell-Yan process ${\pi }^{-}p\to {\mu }^{+}{\mu }^{-}n$ via a spectrometer at the High Momentum Beamline being constructed at J-PARC in Japan. Realization of such measurement at J-PARC will provide a new test of perturbative QCD descriptions of a novel class of hard exclusive reactions. It will also offer the possibility of experimentally accessing nucleon GPDs at large timelike virtuality.

    ↳ nucl-exhep-exhep-phnucl-thPRD(2016)·63 citations
37. 37*

    Response of simple quantum systems to different polarizations of gravitational waves in noncommutative phase-space

    Sunandan Gangopadhyay🇮🇳 · Anirban Saha · Swarup Saha

    Owing to the extreme smallness of any noncommutative scale that may exist in nature, both in the spatial and momentum sector of the quantum phase-space, a credible possibility of their detection lies in the present day gravitational wave detector set-ups, which effectively detects the relative length-scale variations $\mathcal{O}\left[10^{-23}\right]$. With this motivation, we have considered how a free particle and harmonic oscillator in a quantum domain will respond to linearly and circularly polarized gravitational waves if the given phase-space has a noncommutative structure. The results show resonance behaviour in the responses of both free particle and HO systems to GW with both kind of polarizations. We critically analyze all the responses, and their implications in possible detection of noncommutativity. We use the currently available upper-bound estimates on various noncommutative parameters to anticipate the relative size of various response terms. We also argue how the quantum harmonic oscillator system we considered here can be very relevant in context of the resonant bar detectors of GW which are already operational currently.

    ↳ hep-thgr-qchep-phquant-phPRD(2018)·22 citations
38. 38*

    Skyrmion Black Hole Hair: Conservation of Baryon Number by Black Holes and Observable Manifestations

    Gia Dvali🇩🇪 · Alexander Gußmann🇩🇪

    We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

    ↳ hep-thastro-ph.HEgr-qchep-phNPB(2016)·41 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.