Tue·Sep 12, 2017Tuesday·September 12, 2017

1. 01*

   Time-Dependent Observables in Heavy Ion Collisions I: Setting up the Formalism

   Bin Wu🇺🇸 · Yuri V. Kovchegov🇺🇸

   We adapt the Schwinger-Keldysh formalism to study heavy-ion collisions in perturbative QCD. Employing the formalism, we calculate the two-point gluon correlation function $G_{22}^{a\mu ,b\nu }$ due to the lowest-order classical gluon fields in the McLerran-Venugopalan model of heavy ion collisions and observe an interesting transition from the classical fields to the quasi-particle picture at later times. Motivated by this observation, we push the formalism to higher orders in the coupling and calculate the contribution to $G_{22}^{a\mu ,b\nu }$ coming from the diagrams representing a single rescattering between two of the produced gluons. We assume that the two gluons go on mass shell both before and after the rescattering. The result of our calculation depends on the ordering between the proper time of the rescattering ${\tau }_Z$ and the proper time $\tau$ when the gluon distribution is measured. For (i) ${\tau }_Z\gg 1/Q_s$ and $\tau -{\tau }_Z\gg 1/Q_s$ (with $Q_s$ the saturation scale) we obtain the same results as from the Boltzmann equation. For (ii) $\tau -{\tau }_Z\gg {\tau }_Z\gg 1/Q_s$ we end up with a result very different from kinetic theory and consistent with a picture of "free-streaming" particles. Due to the approximations made, our calculation is too coarse to indicate whether the ordering (i) or (ii) is the correct one: to resolve this controversy, we shall present a detailed diagrammatic calculation of the rescattering correction in the ${\phi }^4$ theory in the second paper of this duplex.

   hep-phnucl-exnucl-thJHEP(2018)·12 citations
2. 02*

   Time-Dependent Observables in Heavy Ion Collisions II: in Search of Pressure Isotropization in the ${\phi }^4$ Theory

   Yuri V. Kovchegov🇺🇸 · Bin Wu🇺🇸

   To understand the dynamics of thermalization in heavy ion collisions in the perturbative framework it is essential to first find corrections to the free-streaming classical gluon fields of the McLerran-Venugopalan model. The corrections that lead to deviations from free streaming (and that dominate at late proper time) would provide evidence for the onset of isotropization (and, possibly, thermalization) of the produced medium. To find such corrections we calculate the late-time two-point Green function and the energy-momentum tensor due to a single $2\to 2$ scattering process involving two classical fields. To make the calculation tractable we employ the scalar ${\phi }^4$ theory instead of QCD. We compare our exact diagrammatic results for these quantities to those in kinetic theory and find disagreement between the two. The disagreement is in the dependence on the proper time $\tau$ and, for the case of the two-point function, is also in the dependence on the space-time rapidity $\eta$: the exact diagrammatic calculation is, in fact, consistent with the free streaming scenario. Kinetic theory predicts a build-up of longitudinal pressure, which, however, is not observed in the exact calculation. We conclude that we find no evidence for the beginning of the transition from the free-streaming classical fields to the kinetic theory description of the produced matter after a single $2\to 2$ rescattering.

   hep-phnucl-exnucl-thJHEP(2018)·8 citations
3. 03*

   Dark matter stability and one-loop neutrino mass generation based on Peccei-Quinn symmetry

   Daijiro Suematsu🇯🇵

   We propose a model which is a simple extension of the KSVZ invisible axion model with an inert doublet scalar. Peccei-Quinn symmetry forbids tree-level neutrino mass generation and its remnant $Z_2$ symmetry guarantees dark matter stability. The neutrino masses are generated by one-loop effects as a result of the breaking of Peccei-Quinn symmetry through a nonrenormalizable interaction. Although the low energy effective model coincides with an original scotogenic model which contains right-handed neutrinos with large masses, it is free from the strong $CP$ problem.

   hep-phEPJC(2018)·18 citations
4. 04*

   Cosmological Dark Matter in a Conformal Model

   Prasenjit Sanyal🇮🇳 · Alekha C. Nayak🇮🇳 · Gopal Kashyap🇮🇳 · Pankaj Jain🇮🇳

   We study the collider, astrophysical and cosmological constraints on the dark matter sector of a conformal model within the framework of both the freeze out as well as the freeze in mechanism. The model has a dark sector with strong self interactions. This sector couples weakly with the Standard Model (SM) particles via a scalar messenger. The lightest dark sector particle is a pion-like fermion anti-fermion bound state. We find that the model successfully satisfies the constraints coming from the Higgs decay to the visible as well as the invisible sector. We have used the results of the dark matter direct detection experiments, such as, XENON1T in order to impose bounds on the parameters of the model. The model satisfies the indirect detection constraints of gamma ray from the galactic center and Dwarf spheroidal galaxies. We also determine the parameter range for which it satisfies the astrophysical constraints on the dark matter self coupling.

   hep-phPRD(2019)·3 citations
5. 05*

   ${\sin }^2{\theta }_W$ estimate and neutrino electromagnetic properties from low-energy solar data

   Amir N. Khan🇩🇪

   We report new values of weak-mixing angle (${\sin }^2{\theta }_W$)$,$ neutrino effective magnetic moment and the charge radius using the lowest-energy (to-date) solar neutrino data of pp, ${}^7$Be and pep spectra from phase-I and phase-II runs of Borexino experiment. The best-fit values are ${\sin }^2{\theta }_W=$0.235$\pm$0.019 with a precision comparable to that of the combined reactor and accelerator very short-baseline experiments and ${\mu }_{\nu }^{eff}\le 8.7\times 10^{-12}{\mu }_B$ at 90% C.L. with a factor of 3 improvement than the previous bounds. This leads to the improvement of all the related magnetic moment matrix elements for the Majorana-type and Dirac-type in mass basis and also improvement on bounds on the flavor magnetic moment states. The bounds on the neutrino charged radii turn out to be $-0.82\times 10^{-32}$cm${}^2\le ⟨r_{{\nu }_e}^2⟩\le 1.27\times 10^{-32}$ cm${}^2$and $-9\times 10^{-32}$cm${}^2\le ⟨r_{{\nu }_{\mu },{\nu }_{\tau }}^2⟩\le 3.1\times 10^{-31}$ cm${}^2$ at 90% C.L..

   hep-phhep-exJ.Phys.G(2019)·20 citations
6. 06*

   Exploring hadrons' partonic structure using ab initio lattice QCD calculations

   Yan-Qing Ma🇨🇳 · Jian-Wei Qiu🇺🇸

   Following our previous proposal [1], we construct a class of good "lattice cross sections" (LCSs), from which we could study partonic structure of hadrons from ab initio lattice QCD calculations. These good LCSs, on the one hand, can be calculated directly in lattice QCD, and on the other hand, can be factorized into parton distribution functions (PDFs) with calculable coefficients, in the same way as QCD factorization for factorizable hadronic cross sections. PDFs could be extracted from QCD global analysis of the lattice QCD generated data of LCSs. We also show that proposed functions for lattice QCD calculation of PDFs in the literature are special cases of these good LCSs.

   hep-phhep-latnucl-exnucl-thPRL(2018)·296 citations
7. 07*

   Transverse single-spin asymmetry in the low-virtuality leptoproduction of open charm as a probe of the gluon Sivers function

   Rohini M. Godbole🇮🇳 · Abhiram Kaushik🇮🇳 · Anuradha Misra🇮🇳

   We study the low-virtuality inclusive leptoproduction of open charm, $p^{\uparrow }l\to D^0+X$ as a probe of the gluon Sivers function. We perform the analysis in a generalised parton model framework. At leading order, this process is sensitive only to the gluon content of the proton. Hence any detection of a transverse single-spin asymmetry in this process would be clear indication of a non-zero gluon Sivers function (GSF). Considering COMPASS and a future Electron-Ion Collider (EIC), we present predictions for asymmetry using fits for the GSF available in literature. Predictions for peak asymmetry values lie in the range of 0.8\% to 13\%. We also present estimates of the upper bound on the asymmetry as obtained with a maximal gluon Sivers function. Further, for the case of the Electron-Ion Collider, we evaluate the asymmetry in the muons decaying from the $D$-meson and find that the asymmetry is well preserved in the kinematics of the muons. Peak values of the muon asymmetry are close to those obtained for the $D$-meson and lie in the range $0.75\%$ to 11\%.

   hep-phPRD(2018)·11 citations
8. 08*

   Spectroscopic parameters and decays of the resonance $Z_b(10610)$

   S. S. Agaev🇦🇿 · K. Azizi🇹🇷 · H. Sundu🇹🇷

   The resonance $Z_b(10610)$ is investigated as the diquark-antidiquark $Z_b=[bu][\overline{b}\overline{d}]$ state with spin-parities $J^{PC}=1^{+-}$. The mass and current coupling of the resonance $Z_b(10610)$ are evaluated using QCD two-point sum rule and taking into account the vacuum condensates up to ten dimensions. We study the vertices $Z_b{\rm Y}(nS)\pi (n=1,2,3)$ by applying the QCD light-cone sum rule to compute the corresponding strong couplings $g_{Z_b{\rm Y}(nS)\pi }$ and widths of the decays $Z_b\to {\rm Y}(nS)\pi$. We explore also the vertices $Z_b{h}_b(mP)\pi (m=1,2)$ and calculate the couplings $g_{Z_b{h}_b(mP)\pi }$ and width of the decay channels $Z_b\to h_b(mP)\pi$. To this end, we calculate the mass and decay constants of the $h_b(1P)$ and $h_b(2P)$ mesons. The results obtained are compared with experimental data of the Belle Collaboration.

   hep-phhep-exhep-latEPJC(2017)·22 citations
9. 09*

   pp Elastic Scattering at LHC Proton Structure Outer Cloud - Inner Shell - Gluon Core

   M. M. Islam🇺🇸 · R. J. Luddy🇺🇸

   Our investigation of high energy $\mathrm{pp}$ and $\bar{\mathrm{p}}\mathrm{p}$ elastic scattering over the last two decades has led us to consider that the proton has three regions: i) an outer region consisting of a quark-antiquark ($\mathrm{q}\bar{\mathrm{q}}$) condensate ground state (also described as quark-antiquark outer cloud), ii) an inner shell of baryonic charge of size ~0.44 fm, and iii) a core of size ~0.2 fm, where the three valence quarks of a proton with baryonic charges are confined. The proton structure that has emerged leads to four main elastic scattering processes in $\mathrm{pp}$ scattering. The first process, which gives rise to diffraction scattering, is due to a glancing collision of the outer cloud of one proton with that of another proton. In a $\bar{\mathrm{p}}\mathrm{p}$ glancing collision the corresponding process occurs. The second process involves multiple \omega-exchanges. The third process in $\mathrm{pp}$ scattering is quark-quark scattering via gluon-gluon interaction. The fourth process - which appears for the first time in our investigation of $\mathrm{pp}$ scattering - is a glancing collision at the boundary of a proton cloud with that of the other proton cloud. To describe quantitatively the four processes, their parameters have been determined. For this purpose, we investigated $\mathrm{pp}$ 7 TeV d\sigma/dt measured by the TOTEM Collaboration and $\bar{\mathrm{p}}\mathrm{p}$ 1.96 TeV d\sigma/dt measured by the D0 Collaboration. Our calculated $\mathrm{pp}$ elastic d\sigma/dt at 13 TeV has no oscillations in the large |t| region, in good agreement with the preliminary TOTEM measurements.

   hep-ph3 citations
10. 10*

    On the Validity of the Effective Potential and the Precision of Higgs Self Couplings

    Bithika Jain🇧🇷 · Seung J. Lee🇰🇷 · Minho Son🇰🇷

    The global picture of the Higgs potential in the bottom-up approach is still unknown. A large deviation as big as O(1) fluctuations of the Higgs self couplings is still a viable option for the New Physics. An interesting New Physics scenario which can be linked to a large Higgs self coupling is the baryogenesis based on the strong first order phase transition. We revisit the strong first order phase transition in two classes of Beyond the Standard Models, namely the Higgs portal with the singlet scalar under the Standard Model gauge group with Z2 symmetry and the effective field theory approach with higher-dimensional operators. We numerically investigate a few important issues in the validity of the effective potential, caused by the breakdown of the high-temperature approximation, and in the criteria for the strong first order phase transition. We illustrate that these issues can lead to O(1) uncertainties in the precision of the Higgs self couplings, which are relevant when discussing sensitivity limits of different future colliders. We also find that the quartic coupling of the above two classes of scenarios compatible with the strong first order electroweak phase transition where the cubic coupling is not negligible, can achieve a $2\sigma$ sensitivity at the 100 TeV pp-collider. From this novel observation, we show that the correlation between the Higgs cubic coupling and the quartic coupling will be useful for differentiating various underlying New Physics scenarios and discuss its prospect for the future colliders. Throughout our numerical investigation, the contribution from Goldstone boson is not included.

    hep-phhep-exPRD(2018)·23 citations
11. 11*

    Two aspects of the Regge limit in QCD: Double Logs in Exclusive observables and Infrared Effects in Cross Sections

    G. Chachamis🇪🇸 · A. Sabio Vera🇪🇸 · D. A. Ross🇬🇧

    Two relevant points related to the application of the BFKL formalism to phenomenology are discussed. First, we have presented a set of observables characterizing multi-jet configurations event by event (average transverse momentum, average azimuthal angle, average ratio of jet rapidities) which can be used to find distinct signals of BFKL dynamics at the LHC. A numerical analysis has been shown using the Monte Carlo event generator BFKLex, modified to include higher-order collinear corrections in addition to the transverse-momentum implementation of the NLO kernel. We require to have two tagged forward/backward jets in the final state. Second, the structure of the BFKL equation changes if infrared boundary conditions are imposed when considering the running of the coupling. The cut in the complex angular momentum plane becomes an infinite series of Regge poles. Integrating along a contour off the real axis we find a strong dependence of the intercepts and collinear regions on the choice of the boundary conditions. The mean transverse scales dominant in the gluon ladder increase. This could have interesting phenomenological consequences.

    hep-phhep-thPoS(2018)·0 citations
12. 12*

    CSM tests in $gb\to \gamma b,Hb,Zb,W^{-}t$ processes

    Fernand M Renard🇫🇷

    We show that the processes of $\gamma b,Hb,Zb,W^{-}t$ production in gluon+bottom collision can give interesting informations about possible Higgs boson, top and bottom quark compositeness. We make illustrations of the ratios of new cross sections over standard ones. Specific energy dependences appear for each assumption about $b_L$, $b_R$, $t_L$, $t_R$ compositeness and CSM constraints concerning the Higgs sector.

    hep-ph0 citations
13. 13*

    Automatic calculation of two-loop ELWK corrections to the muon ($g$-2)

    Tadashi Ishikawa (1)🇯🇵 · Nobuya Nakazawa (2)🇯🇵 · Yoshiaki Yasui (3) ((1) High Energy Accelerator Organization (KEK), Tsukuba Ibaraki, Japan (2) Department of Physics, Kogakuin University, Shinjuku, Tokyo, Japan (3) Department of Management, Tokyo Management College, Ichikawa, Chiba Japan)🇯🇵

    Two-loop electroweak corrections to the muon anomalous magnetic moment are automatically calculated by using GRACE-FORM system, as a trial to extend our system for two-loop calculation. We adopt the non-linear gauge (NLG) to check the reliability of our calculation. In total 1780 two-loop diagrams consisting of 14 different topological types and 70 one-loop diagrams composed of counter terms are calculated. We check UV- and IR-divergences cancellation and the independence of the results from NLG parameters. As for the numerical calculation, we adopt trapezoidal rule with Double Exponential method (DE). Linear extrapolation method (LE) is introduced to regularize UV- and IR- divergence and to get finite values.

    hep-phJ.Phys.Conf.Ser.(2017)·4 citations
14. 14*

    Extraction of partonic transverse momentum distributions from semi-inclusive deep inelastic scattering and Drell-Yan data

    Cristian Pisano🇮🇹 · Alessandro Bacchetta🇮🇹 · Filippo Delcarro🇮🇹 · Marco Radici🇮🇹 · Andrea Signori🇺🇸

    We present a first attempt at a global fit of unpolarized quark transverse momentum dependent distribution and fragmentation functions from available data on semi-inclusive deep-inelastic scattering, Drell-Yan and $Z$ boson production processes. This analysis is performed in the low transverse momentum region, at leading order in perturbative QCD and with the inclusion of energy scale evolution effects at the next-to-leading logarithmic accuracy.

    hep-phPoS(2018)·1 citation
15. 15*

    The quark propagators of QCD and QCD-like theories

    Romain Contant🇦🇹 · Markus Q. Huber🇦🇹

    We investigate the phase structures of theories which differ from QCD only in the gauge group and can be simulated on the lattice at non-vanishing chemical potential $\mu$. These theories can thus serve as testing ground for functional methods at non-vanishing density. We determine the chiral and confinement/deconfinement transitions at $\mu =0$ for the three gauge groups $SU(3)$, $SU(2)$ and $G_2$ for two quark flavors and extend the study of the chiral transition to non-zero $\mu$. We locate the critical point where the chiral crossover becomes a real phase transition. Within the employed truncation, we find that all three theories behave qualitatively very similarly.

    hep-phhep-latActa Phys.Polon.Supp.(2017)·7 citations
16. 16*

    Holomorphic Scalar Portals and the OPE

    Jean-François Fortin🇨🇦 · Shanny Pelchat-Voyer🇨🇦

    Visible-sector SUSY-breaking effects are computed in terms of hidden-sector correlation functions for generic holomorphic scalar portals. The solutions, which are valid irrespective of the hidden-sector dynamics, are approximated with the help of the operator product expansion (OPE). Indeed, for theories with superconformal symmetry at high energy, the superconformal OPE formalism can be used to disentangle the high-energy dynamics, encoded in the OPE coefficients, from the low-energy dynamics of the SUSY-breaking vacuum expectation values. A systematic method is proposed to compute the OPE coefficients, using relations between correlation functions of superfields and correlation functions of their quasi-primary component fields. The method, which is quite general, could be useful in building models of gauge- or gravity-mediated SUSY breaking and in analysing the viability of such models in a systematic way.

    hep-phhep-thJHEP(2017)·2 citations
17. 17*

    Lepton number violation phenomenology of d=7 neutrino mass models

    R. Cepedello🇪🇸 · M. Hirsch🇪🇸 · J.C. Helo🇨🇱

    We study the phenomenology of d=7 1-loop neutrino mass models. All models in this particular class require the existence of several new $SU(2{)}_L$ multiplets, both scalar and fermionic, and thus predict a rich phenomenology at the LHC. The observed neutrino masses and mixings can easily be fitted in these models. Interestingly, despite the smallness of the observed neutrino masses, some particular lepton number violating (LNV) final states can arise with observable branching ratios. These LNV final states consists of leptons and gauge bosons with high multiplicities, such as 4l+4W, 6l+2W, etc. We study current constraints on these models from upper bounds on charged lepton flavour violating decays, existing lepton number conserving searches at the LHC and discuss possible future LNV searches.

    hep-phJHEP(2018)·32 citations
18. 18*

    Fragmentation functions of charged hadrons

    Emanuele R. Nocera🇬🇧

    I present a preliminary determination of the Fragmentation Functions (FFs) of unidentified charged hadrons at next-to-leading order in quantum chromodynamics. The analysis is based on hadron production cross section data in single-inclusive electron-positron annihilation. It extends a recent determination of the FFs of identified charged pions, charged kaons and protons/antiprotons performed by the NNPDF Collaboration. I illustrate the quality of the FFs determined in this analysis and show how they describe the charged hadron spectra measured in proton-(anti)proton collisions.

    hep-phPoS(2018)·6 citations
19. 19*

    What Quark-Gluon Plasma in small systems might tell us about nucleons

    Peter Christiansen🇸🇪

    The origin of flow-like effects in small systems, such as those produced in ultra-relativistic proton-proton and proton-lead collisions, is still widely debated. In this paper the goal is to look at possible consequences if indeed a mini-Quark-Gluon Plasma is formed in these collisions. It is argued that this could indicate a duality between the QGP phase and the color fields in hadrons. A qualitative dense field picture is presented for this duality and discussed.

    hep-ph0 citations
20. 20*

    Asymptotically Free Theory with Scale Invariant Thermodynamics

    Gabriel N. Ferrari🇧🇷 · Jean-Loic Kneur🇫🇷 · Marcus B. Pinto🇧🇷 · Rudnei O. Ramos🇧🇷

    A recently developed variational resummation technique, incorporating renormalization group properties consistently, has been shown to solve the scale dependence problem that plagues the evaluation of thermodynamical quantities, e.g., within the framework of approximations such as in the hard-thermal-loop resummed perturbation theory. This method is used in the present work to evaluate thermodynamical quantities within the two-dimensional nonlinear sigma model, which, apart from providing a technically simpler testing ground, shares some common features with Yang-Mills theories, like asymptotic freedom, trace anomaly and the nonperturbative generation of a mass gap. The present application confirms that nonperturbative results can be readily generated solely by considering the lowest-order (quasi-particle) contribution to the thermodynamic effective potential, when this quantity is required to be renormalization group invariant. We also show that when the next-to-leading correction from the method is accounted for, the results indicate convergence, apart from optimally preserving, within the approximations here considered, the sought-after scale invariance.

    hep-phhep-thnucl-thPRD(2017)·9 citations
21. 21*

    Perturbativity Constraints in BSM Models

    Manuel E. Krauss🇩🇪 · Florian Staub🇩🇪

    Phenomenological studies performed for non-supersymmetric extensions of the Standard Model usually use tree-level parameters as input to define the scalar sector of the model. This implicitly assumes that a full on-shell calculation of the scalar sector is possible - and meaningful. However, this doesn't have to be the case as we show explicitly at the example of the Georgi-Machacek model. This model comes with an appealing custodial symmetry to explain the smallness of the $\rho$ parameter. However, the model cannot be renormalised on-shell without breaking the custodial symmetry. Moreover, we find that it can often happen that the radiative corrections are so large that any consideration based on a perturbative expansion appears to be meaningless: counter-terms to quartic couplings can become much larger than $4\pi$ and/or two-loop mass corrections can become larger than the one-loop ones. Therefore, conditions are necessary to single out parameter regions which cannot be treated perturbatively. We propose and discuss different sets of such perturbativity conditions and show their impact on the parameter space of the Georgi-Machacek model. Moreover, the proposed conditions are general enough that they can be applied to other models as well. We also point out that the vacuum stability constraints in the Georgi-Machacek model, which have so far only been applied at the tree level, receive crucial radiative corrections. We show that large regions of the parameter space which feature a stable electroweak vacuum at the loop level would have been - wrongly - ruled out by the tree-level conditions.

    hep-phhep-exEPJC(2018)·32 citations
22. 22*

    Jet and photon measurements with ATLAS

    Benjamin Nachman🇺🇸

    The strong force is responsible for a rich set of phenomena that can be probed using a variety of techniques over a wide energy and angular range at the Large Hadron Collider. This talk reports on the latest results from the ATLAS Collaboration that measure the high energy, wide angle, collinear, and soft regimes of quantum chromodynamics (QCD). There is also an important connection between QCD at high energies and electroweak phenomena including massive gauge bosons as well as photons.

    ↳ hep-exhep-ph1 citation
23. 23*

    Shear viscosity of a pion gas due to $\rho \pi \pi$ and $\sigma \pi \pi$ interactions

    Sabyasachi Ghosh🇧🇷 · Gastao Krein🇧🇷 · Saurav Sarkar🇮🇳

    We have calculated the shear viscosity of pion medium, where propagating pion has some finite thermal width due to interaction with the low mass resonances, $\sigma$ and $\rho$. With the help of standard thermal field theoretical technique, the thermal width of the pion has been calculated from the pion self-energy diagram for $\pi \sigma$ and $\pi \rho$ loops, where an effective Lagrangian density has been used for interaction part. We have found a very small value of shear viscosity by entropy density ratio ($\eta /s$), which is very close to the KSS bound.

    ↳ nucl-thhep-phPoS(2017)·0 citations
24. 24*

    The status of varying constants: a review of the physics, searches and implications

    C. J. A. P. Martins🇵🇹

    The observational evidence for the recent acceleration of the universe demonstrates that canonical theories of cosmology and particle physics are incomplete---if not incorrect---and that new physics is out there, waiting to be discovered. A key task for the next generation of laboratory and astrophysical facilities is to search for, identify and ultimately characterize this new physics. Here we highlight recent developments in tests of the stability of nature's fundamental couplings, which provide a direct handle on new physics: a detection of variations will be revolutionary, but even improved null results provide competitive constraints on a range of cosmological and particle physics paradigms. A joint analysis of all currently available data shows a preference for variations of $\alpha$ and $\mu$ at about the two-sigma level, but inconsistencies between different sub-sets (likely due to hidden systematics) suggest that these statistical preferences need to be taken with caution. On the other hand, these measurements strongly constrain Weak Equivalence Principle violations. Plans and forecasts for forthcoming studies with facilities such as ALMA, ESPRESSO and the ELT, which should clarify these issues, are also discussed, and synergies with other probes are briefly highlighted. The goal is to show how a new generation of precision consistency tests of the standard paradigm will soon become possible.

    ↳ astro-ph.COgr-qchep-phhep-th125 citations
25. 25*

    Highlights and Perspectives from the CMS Experiment

    Joel Nathan Butler🇺🇸

    In 2016, the Large Hadron Collider provided proton-proton collisions at 13 TeV center-of-mass energy and achieved very high luminosity and reliability. The performance of the CMS Experiment in this running period and a selection of recent physics results are presented. These include precision measurements and searches for new particles. The status and prospects for data-taking in 2017 and a brief summary of the highlights of the High Luminosity (HL-LHC) upgrade of the CMS detector are also presented.

    ↳ hep-exhep-ph12 citations
26. 26*

    Recent Results on Radiative and Electroweak Penguin decays at Belle

    S. Sandilya🇺🇸

    We report on the measurement of the decay $B\to K^{\star }\gamma$, lepton-flavor dependent angular analysis of the decay $B\to K^{\star }\ell \ell$, and search for the decays $B\to h\nu \nu$. All these analyses are performed on the 711 $f{b}^{-1}$ data sample recorded by the Belle detector at the ${\rm Y}(4S)$ resonance.

    ↳ hep-exhep-ph0 citations
27. 27*

    On the Prospects for Detecting a Net Photon Circular Polarization Produced by Decaying Dark Matter

    Andrey Elagin🇺🇸 · Jason Kumar🇺🇸 · Pearl Sandick🇺🇸 · Fei Teng🇺🇸

    If dark matter interactions with Standard Model particles are $CP$-violating, then dark matter annihilation/decay can produce photons with a net circular polarization. We consider the prospects for experimentally detecting evidence for such a circular polarization. We identify optimal models for dark matter interactions with the Standard Model, from the point of view of detectability of the net polarization, for the case of either symmetric or asymmetric dark matter. We find that, for symmetric dark matter, evidence for net polarization could be found by a search of the Galactic Center by an instrument sensitive to circular polarization with an efficiency-weighted exposure of at least $50000{\text{cm}}^2\text{yr}$, provided the systematic detector uncertainties are constrained at the $1\%$ level. Better sensitivity can be obtained in the case of asymmetric dark matter. We discuss the prospects for achieving the needed level of performance using possible detector technologies.

    ↳ astro-ph.COastro-ph.IMhep-phPRD(2017)·12 citations
28. 28*

    Homogeneous isotropization and equilibration of a strongly coupled plasma with a critical point

    Renato Critelli (1)🇧🇷 · Romulo Rougemont (2)🇧🇷 · Jorge Noronha (1) ((1) Sao Paulo U., (2) IIP, Brazil)🇧🇷

    We use holography to investigate the process of homogeneous isotropization and thermalization in a strongly coupled $\mathcal{N}=4$ Super Yang-Mills plasma charged under a $U(1)$ subgroup of the global $SU(4)$ R-symmetry which features a critical point in its phase diagram. Isotropization dynamics at late times is affected by the critical point in agreement with the behavior of the characteristic relaxation time extracted from the analysis of the lowest non-hydrodynamic quasinormal mode in the $SO(3)$ quintuplet (external scalar) channel of the theory. In particular, the isotropization time may decrease or increase as the chemical potential increases depending on whether one is far or close enough to the critical point, respectively. On the other hand, the thermalization time associated with the equilibration of the scalar condensate, which happens only after the system has relaxed to a (nearly) isotropic state, is found to always increase with chemical potential in agreement with the characteristic relaxation time associated to the lowest non-hydrodynamic quasinormal mode in the $SO(3)$ singlet (dilaton) channel. These conclusions about the late dynamics of the system are robust in the sense that they hold for different initial conditions seeding the time evolution of the far-from-equilibrium plasma.

    ↳ hep-thhep-phnucl-thJHEP(2017)·38 citations
29. 29*

    A first step towards the inflationary trans-planckian problem treatment in Loop Quantum Cosmology

    Killian Martineau🇫🇷 · Aurélien Barrau🇫🇷 · Julien Grain🇫🇷

    For most initial conditions, cosmologically relevant physical modes were trans-planckian at the bounce time, often by many magnitude orders. We improve the usual loop quantum cosmology calculation of the primordial power spectra -- in the inflationary framework -- by accounting for those trans-planckian effects through modified dispersion relations. This can induce drastic changes in the spectrum, making it either compatible or incompatible with observational data, depending on the details of the choices operated.

    ↳ gr-qcastro-ph.COhep-phInt.J.Mod.Phys.D(2018)·16 citations
30. 30*

    $b\bar{b}u\bar{d}$ four-quark systems in the Born-Oppenheimer approximation: prospects and challenges

    Antje Peters🇩🇪 · Pedro Bicudo🇵🇹 · Marc Wagner🇩🇪

    We summarize previous work on $\bar{b}\bar{b}ud$ four-quark systems in the Born-Oppenheimer approximation and discuss first steps towards an extension to the theoretically more challenging $b\bar{b}u\bar{d}$ system. Strategies to identify a possibly existing $b\bar{b}u\bar{d}$ bound state are discussed and first numerical results are presented.

    ↳ hep-lathep-phEPJ Web Conf.(2018)·11 citations
31. 31*

    Neutrino Interferometry for High-Precision Tests of Lorentz Symmetry with IceCube

    IceCube Collaboration: M. G. Aartsen🇳🇿 · M. Ackermann🇩🇪 · J. Adams🇳🇿 · J. A. Aguilar🇧🇪 · M. Ahlers🇩🇰 · M. Ahrens🇸🇪 · I. Al Samarai🇨🇭 · D. Altmann🇩🇪 · K. Andeen🇺🇸 · T. Anderson🇺🇸 · I. Ansseau🇧🇪 · G. Anton🇩🇪 and 310 other authors

    Lorentz symmetry is a fundamental space-time symmetry underlying the Standard Model of particle physics and gravity. However, unified theories, such as string theory, allow for violation of this symmetry. Thus, the discovery of Lorentz symmetry violation could be the first hint of these theories. Here, we use high-energy atmospheric neutrinos observed at the IceCube Neutrino Observatory to search for anomalous neutrino oscillations as signals of Lorentz violation. The large range of neutrino energies and propagation baselines, together with high statistics, let us perform the most precise test of space-time symmetry in the neutrino sector to date. We find no evidence for Lorentz violation. This allows us to constrain the size of the dimension-four operator in the Standard-Model Extension for Lorentz violation to the $10^{-28}$ level and to set limits on higher dimensional operators of that theory. These are among the most stringent limits on Lorentz violation across all fields of physics.

    ↳ hep-exhep-phNat.Phys.(2018)·140 citations
32. 32*

    Pole inflation in Jordan frame supergravity

    Ken'ichi Saikawa🇩🇪 · Masahide Yamaguchi🇯🇵 · Yasuho Yamashita🇯🇵 · Daisuke Yoshida🇨🇦

    We investigate inflation models in Jordan frame supergravity, in which an inflaton non-minimally couples to the scalar curvature. By imposing the condition that an inflaton would have the canonical kinetic term in the Jordan frame, we construct inflation models with asymptotically flat potential through pole inflation technique and discuss their relation to the models based on Einstein frame supergravity. We also show that the model proposed by Ferrara et al. has special position and the relation between the Kähler potential and the frame function is uniquely determined by requiring that scalars take the canonical kinetic terms in the Jordan frame and that a frame function consists only of a holomorphic term (and its anti-holomorphic counterpart) for symmetry breaking terms. Our case corresponds to relaxing the latter condition.

    ↳ hep-thastro-ph.COgr-qchep-phJCAP(2018)·5 citations
33. 33*

    Using LISA-like Gravitational Wave Detectors to Search for Primordial Black Holes

    Huai-Ke Guo🇨🇳 · Jing Shu🇨🇳 · Yue Zhao🇺🇸

    Primordial black hole (PBH), which can be naturally produced in the early universe, remains a promising dark matter candidate . It can merge with a supermassive black hole (SMBH) in the center of a galaxy and generate gravitational wave (GW) signals in the favored frequency region of LISA-like experiments. In this work, we initiate the study on the event rate calculation for such extreme mass ratio inspirals (EMRI). Including the sensitivities of various proposed GW detectors, we find that such experiments offer a novel and outstanding tool to test the scenario where PBH constitutes (fraction of) dark matter. The PBH energy density fraction of DM ($f_{\text{PBH}}$) could potentially be explored as small as $10^{-3}\sim 10^{-4}$. Further, LISA has the capability to search for PBH mass upto $10^{-2}\sim 10^{-1}{M}_{\odot }$. Other proposed GW experiments can probe lower PBH mass regime.

    ↳ astro-ph.COhep-phPRD(2019)·38 citations
34. 34*

    String Geometry and Non-perturbative Formulation of String Theory

    Matsuo Sato🇯🇵

    We define string geometry: spaces of superstrings including the interactions, their topologies, charts, and metrics. Trajectories in asymptotic processes on a space of strings reproduce the right moduli space of the super Riemann surfaces in a target manifold. Based on the string geometry, we define Einstein-Hilbert action coupled with gauge fields, and formulate superstring theory non-perturbatively by summing over metrics and the gauge fields on the spaces of strings. This theory does not depend on backgrounds. The theory has a supersymmetry as a part of the diffeomorphisms symmetry on the superstring manifolds. We derive the all-order perturbative scattering amplitudes that possess the super moduli in type IIA, type IIB and SO(32) type I superstring theories from the single theory, by considering fluctuations around fixed backgrounds representing type IIA, type IIB and SO(32) type I perturbative vacua, respectively. The theory predicts that we can see a string if we microscopically observe not only a particle but also a point in the space-time. That is, this theory unifies particles and the space-time.

    ↳ hep-thhep-phmath.DGmath.FA+1Int.J.Mod.Phys.A(2019)·16 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.