Thu·Oct 18, 2018Thursday·October 18, 2018

1. 01*

   Vector dark matter production at the end of inflation

   Mar Bastero-Gil🇪🇸 · Jose Santiago🇪🇸 · Lorenzo Ubaldi🇮🇹 · Roberto Vega-Morales🇪🇸

   It has been shown that the longitudinal mode of a massive vector boson can be produced by inflationary fluctuations and account for the dark matter content of the Universe. In this work we examine the possibility of instead producing the transverse mode via the coupling $\varphi F\tilde{F}$ between the inflaton and the vector field strength. Such a coupling leads to a tachyonic instability and exponential production of one transverse polarization of the vector field, reaching its maximum near the end of inflation. At production the mass is negligible and the vectors add up coherently to form a dark electromagnetic field. As the Universe expands, the energy density of the dark electromagnetic field then redshifts like radiation until its wavelength stretches to beyond its Compton wavelength. After this point the vectors become non-relativistic and their energy density redshifts like matter. We show that these polarized transverse vectors can account for the observed dark matter relic density in the mass range $\mu$eV to hundreds of GeV. We also find that the tachyonic production mechanism of the transverse mode can accommodate larger vector masses and lower Hubble scales of inflation compared to the production mechanism for the longitudinal mode via inflationary fluctuations.

   hep-phJCAP(2019)·218 citations
2. 02*

   Majorana vs Pseudo-Dirac Neutrinos at the ILC

   P. Hernández🇪🇸 · J. Jones-Pérez🇵🇪 · O. Suarez-Navarro🇵🇪

   Neutrino masses could originate in seesaw models testable at colliders, with light mediators and an approximate lepton number symmetry. The minimal model of this type contains two quasi-degenerate Majorana fermions forming a pseudo-Dirac pair. An important question is to what extent future colliders will have sensitivity to the splitting between the Majorana components, since this quantity signals the breaking of lepton number and is connected to the light neutrino masses. We consider the production of these neutral heavy leptons at the ILC, where their displaced decays provide a golden signal: a forward-backward charge asymmetry, which depends crucially on the mass splitting between the two Majorana components. We show that this observable can constrain the mass splitting to values much lower than current bounds from neutrinoless double beta decay and natural loop corrections.

   hep-phEPJC(2019)·59 citations
3. 03*

   Exploring vector-like supersymmetric extensions of the Standard Model with dark matter and colliders

   Jack Y. Araz🇨🇦 · Shankha Banerjee🇬🇧 · Mariana Frank🇨🇦 · Benjamin Fuks🇫🇷 · Andreas Goudelis🇫🇷

   Motivated by grand unification considerations, we analyze a simple extension of the minimal supersymmetric standard model with additional pairs of vector-like chiral supermultiplets. We focus on the so-called LND setup, which enlarges the particle content of the minimal model by two vector-like pairs of weak doublets (one pair of leptons and one pair of down-type quarks) and one vector-like pair of neutrino singlets. Imposing collider and low-energy constraints, sneutrinos and neutralinos both emerge as possible lightest supersymmetric particles and thus dark matter candidates. We perform a complete analysis of the dark sector and study the viability of these neutralino and sneutrino dark matter options. We show that cosmological considerations (the dark matter relic abundance and its direct and indirect detection signals) restrict neutralino dark matter to exhibit similar properties as in the minimal supersymmetric standard model, and impose the sneutrino dark matter candidate to be singlet-like, rather than doublet-like. Allowing the mixing of the fermionic component of the new supermultiplets with the Standard Model third generation fermions, we moreover demonstrate the existence of collider signals that are distinguishable from other, more minimal, supersymmetric scenarios by virtue of an enhanced production of events enriched in tau leptons. We furthermore show that this signature yields robust LHC signals, that could potentially be differentiated from the background in future data.

   hep-phPRD(2018)·15 citations
4. 04*

   Production of $p\bar{p}$ pairs in UPC at the LHC

   Piotr Lebiedowicz🇵🇱 · Mariola Kłusek-Gawenda🇵🇱 · Antoni Szczurek🇵🇱 · Otto Nachtmann🇩🇪

   We discuss production of $p\bar{p}$ pairs in two-photon interactions in heavy-ion collisions. We present predictions for the ultraperipheral, ultrarelativistic, heavy-ion collisions (UPC) ${}^{208}Pb{}^{208}Pb\to$ ${}^{208}Pb{}^{208}Pbp\bar{p}$. The parameters of vertex form factors are adjusted to the Belle data for the $\gamma \gamma \to p\bar{p}$ reaction. To described the Belle data we include the proton-exchange, the $f_2(1270)$ and $f_2(1950)$ $s$-channel exchanges, as well as the hand-bag mechanism. Then, the total cross section and several differential distributions for experimental cuts corresponding to the LHC experiments are presented. The distribution in ${\mathrm{y}}_{diff}$, the rapidity distance between the proton and antiproton, is particularly interesting. We find the total cross sections: 100 $\mu$b for the ALICE cuts, 160 $\mu$b for the ATLAS cuts, 500 $\mu$b for the CMS cuts, and 104 $\mu$b taking into account the LHCb cuts. This opens a possibility to study the $\gamma \gamma \to p\bar{p}$ process in UPC at the LHC.

   hep-phActa Phys. Polon. B Proc. Supp. 12 (2019)…·2 citations
5. 05*

   Radiative decay of hadronic molecule state for quarks

   Xiaozhao Chen🇨🇳 · Xiaofu Lü🇨🇳 · Renbin Shi🇨🇳 · Xiurong Guo🇨🇳 · Qingbiao Wang🇨🇳

   Using the general form of the generalized Bethe-Salpeter wave functions for four-quark states describing the meson-meson molecular structure given in our previous work, we obtain the general formulas for the decay widths of molecular states composed of two vector mesons with arbitrary spin and parity into two photons. Then this general formalism is applied to investigate the radiative two-photon decay of the obeserved \emph{X}(3915) state, where this exotic state \emph{X}(3915) is considered as a molecular state consisting of two heavy vector mesons $D^{\ast 0}{\bar{D}}^{\ast 0}$. The numerical result of decay mode $\text{X}(3915)\to \gamma \gamma$ is consistent with the experimental values.

   hep-phPRD(2020)·6 citations
6. 06*

   Probing Electroweakly Interacting Massive Particles with Drell-Yan Process at 100 TeV Hadron Colliders

   So Chigusa🇯🇵 · Yohei Ema🇩🇪 · Takeo Moroi🇯🇵

   There are many models beyond the standard model which include electroweakly interacting massive particles (EWIMPs), often in the context of the dark matter. In this paper, we study the indirect search of EWIMPs using a precise measurement of the Drell-Yan cross sections at future $100\mathrm{TeV}$ hadron colliders. It is revealed that this search strategy is suitable in particular for Higgsino and that the Higgsino mass up to about $1.3\mathrm{TeV}$ will be covered at $95\%$ C.L. irrespective of the chargino and neutralino mass difference. We also show that the study of the Drell-Yan process provides important and independent information about every kind of EWIMP in addition to Higgsino.

   hep-phPLB(2019)·16 citations
7. 07*

   High-energy neutrino-nucleus interactions

   S. Kumano🇯🇵

   High-energy neutrino-nucleus interactions are discussed by considering neutrino-oscillation experiments and ultra-high-energy cosmic neutrino interactions. The largest systematic error for the current neutrino oscillation measurements comes from the neutrino-nucleus interaction part, and its accurate understanding is essential for high-precision neutrino physics, namely for studying CP violation in the lepton sector. Depending on neutrino beam energies, quasi-elastic, resonance, Regge, or/and deep inelastic scattering (DIS) processes contribute to the neutrino cross section. It is desirable to have a code to calculate the neutrino-nucleus cross section in any kinematical range by combining various theoretical descriptions. On the other hand, the IceCube collaboration started obtaining cross section data up to the $10^{15}$ eV range, so that it became necessary to understand ultra-high-energy neutrino interactions beyond the artificial lepton-accelerator energy range. For future precise neutrino physics including the CP measurement, it is also necessary to understand accurate nuclear corrections. The current status is explained for nuclear corrections in DIS structure functions. The possibility is also discussed to find gravitational sources within nucleons and nuclei, namely matrix elements of quark-gluon energy-momentum tensor. They could be probed by neutrino interactions without replying on direct ultra-weak "gravitational interactions" with high-intensity neutrino beams, possibly at a future neutrino factory, by using techniques of hadron tomography.

   hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2019)·2 citations
8. 08*

   DIS at small x and hadron-hadron scattering at high energies via the holographic Pomeron exchange

   Akira Watanabe🇨🇳

   We present our analysis on the high energy scattering processes in the framework of the holographic QCD, assuming that the Pomeron exchange gives a dominant contribution to the cross sections. Focusing on the two-body scattering, we employ the Brower-Polchinski-Strassler-Tan Pomeron exchange kernel to describe the strong gluonic interaction, and utilize the bottom-up AdS/QCD models to obtain the density distributions of the involved hadrons in the five-dimensional AdS space, to calculate the total cross sections. Considering the unpolarized deep inelastic scattering at small Bjorken $x$ and the high energy hadron-hadron scattering, we show that our calculations are consistent with the presently available experimental data. Our predictions made via this framework can be tested at various experimental facilities in the future.

   hep-phnucl-thPhys.Part.Nucl.Lett.(2019)·2 citations
9. 09*

   Probing the nonstandard top-gluon couplings through $t\bar{t}\gamma \gamma$ production at the LHC

   Seyed Mohsen Etesami🇮🇷 · Esmat Darvish Roknabadi🇮🇷

   In this paper, we investigate the anomalous chromoelectric and chromomagnetic dipole moments of the top quark through top pair production in association with two photons at the LHC. We first present the strategy to reconstruct this process assuming a different source for background processes. Then, we focus on the existing constraints from inclusive top-pair production from the Tevatron and LHC, adding the new LHC measurement. Afterwards, we introduce the new cross section ratio $R_{2\gamma /\gamma }={\sigma }_{t\bar{t}\gamma \gamma }/{\sigma }_{t\bar{t}\gamma }$ and show the usefulness of this ratio in canceling most of the systematic uncertainties and its special functionality to constrain dipole moments. Finally, we use the scalar sum of the transverse momentum of jets, $H_T$, in order to define a signal-dominated region and obtain limits on these anomalous top couplings using different amounts of expected data from the LHC.

   hep-phPRD(2019)·9 citations
10. 10*

    Semi-classical limitations for photon emission in strong external fields

    E. Raicher🇩🇪 · S. Eliezer🇮🇱 · C.H. Keitel🇩🇪 · K.Z. Hatsagortsyan🇩🇪

    The semi-classical heuristic emission formula of Baier-Katkov [Sov. Phys. JETP \textbf{26}, 854 (1968)] is well-known to describe radiation of an ultrarelativistic electron in strong external fields employing the electron's classical trajectory. To find the limitations of the Baier-Katkov approach, we investigate electron radiation in a strong rotating electric field quantum mechanically using the Wentzel-Kramers-Brillouin approximation. Except for an ultrarelativistic velocity, it is shown that an additional condition is required in order to recover the widely used semi-classical result. A violation of this condition leads to two consequences. First, it gives rise to qualitative discrepancy in harmonic spectra between the two approaches. Second, the quantum harmonic spectra are determined not only by the classical trajectory but also by the dispersion relation of the effective photons of the external field.

    hep-phPRA(2019)·12 citations
11. 11*

    Kinetic Mixing and Portal Matter Phenomenology

    Thomas G. Rizzo🇺🇸

    Dark photons (DP) are interesting as potential mediators between the dark matter (DM) sector and the fields of the Standard Model (SM). The interaction of the DP, described by a broken $U(1{)}_D$ gauge symmetry, with the SM is usually generated at the one-loop level via kinetic mixing through the existence of portal matter (PM), here assumed to be fermionic, which carries both a dark charge as well as a SM $U(1{)}_Y$ hypercharge. For theoretical consistency, as well as for many phenomenological reasons, this PM must be vector-like with respect to the SM and dark gauge groups and, in particular, is shown to be allowed only to transform as vector-like copies of the usual SM fields. The dark Higgs that is responsible for the breaking of $U(1{)}_D$ can then generate a mixing between the PM and SM fields with the same electric charge thus altering the DP interactions with (at least some of) the SM fields and also providing a path for the PM fields to decay. In this paper we briefly explore the phenomenology of some specific simple models of this PM including, for the case where the PM is leptonic in nature, their potential impact on experiments probing low energy parity-violation and the g-2 of the muon. In the case of color-triplet, bottom quark-like PM, their direct pair- and single-production at the LHC is shown to be observable in final states that include missing $E_T$ and/or very highly boosted lepton-jets together with pairs of high $p_T$ b-jets that can be used to trigger on such events. These signatures are quite distinct from those usually employed in the search for vector-like quarks at the LHC and, furthermore, we demonstrate that the conventional signal channels for vector-like quarks involving the SM Higgs and gauge fields are essentially closed in the case of PM.

    hep-phPRD(2019)·53 citations
12. 12*

    $S=-1$ meson-baryon interaction and the role of isospin filtering processes

    Albert Feijoo🇨🇿 · Volodymyr Magas🇪🇸 · Angels Ramos🇪🇸

    A study of the meson-baryon interaction in the $S=-1$ sector is performed, employing a chiral SU(3) lagrangian up to next-to-leading order (NLO) and implementing unitarization in coupled channels. The model is constrained by a large set of experimental data, paying a especial attention to processes that are sensitive to the NLO contributions, such as the $K^{-}p\to K^{+}{\Xi }^{-},K^0{\Xi }^0$ reactions. The consideration of additional cross sections in single isospin channels, $K^{-}p\to \eta \Lambda ,\eta \Sigma$, has been found to provide more homogeneous and reliable values of the low-energy constants, the stability of which has also been tested by the inclusion of explicit resonant terms. Predictions for new isospin filtering processes, like the $I=1$ $K_L^{0}p\to K^{+}{\Xi }^0$ reaction that could be measured at the proposed secondary $K_L^0$ beam at Jlab, or the weak decay of the ${\Lambda }_b$ into a $J/\Psi$ and different meson-baryon pairs in $I=0$, available at LHCb, are presented. The measurement of such reactions would put valuable constraints on the chiral models describing the $S=-1$ meson-baryon interaction.

    hep-phPRC(2019)·73 citations
13. 13*

    Non-congruent phase transitions in strongly interacting matter within the Quantum van der Waals model

    Roman Poberezhnyuk🇺🇦 · Volodymyr Vovchenko🇩🇪 · Mark I. Gorenstein🇺🇦 · Horst Stoecker🇩🇪

    The non-congruent liquid-gas phase transition (LGPT) in asymmetric nuclear matter is studied using the recently developed Quantum van der Waals model in the grand canonical ensemble. Different values of the electric-to-baryon charge ratio, $Q/B$, are considered. This non-congruent LGPT exhibits several features which are not present in the congruent LGPT of symmetric nuclear matter. These include a continuous phase transformation, a change in the location of the critical point, and the separation of the critical point and the endpoints. The effects which are associated with the non-congruent LGPT become negligible for the following cases: when $Q/B$ approaches its limiting values, $0.5$ or $0$, or if quantum statistical effects can be neglected. The latter situation is realized when the particle degeneracy attains large values, $g\gtrsim 10$.

    hep-phnucl-thPRC(2019)·23 citations
14. 14*

    Semi-analytical calculation of gluon fragmentation into ${}^1{S}_0^{[1,8]}$ quarkonia at next-to-leading order

    Peng Zhang🇨🇳 · Chen-Yu Wang🇨🇳 · Xiao Liu🇨🇳 · Yan-Qing Ma🇨🇳 · Ce Meng🇨🇳 · Kuang-Ta Chao🇨🇳

    We calculate the NLO corrections for the gluon fragmentation functions to a heavy quark-antiquark pair in ${}^1{S}_0^{[1]}$ or ${}^1{S}_0^{[8]}$ state within NRQCD factorization. We use integration-by-parts reduction to reduce the original expression to simpler master integrals (MIs), and then set up differential equations for these MIs. After calculating the boundary conditions, MIs can be obtained by solving the differential equations numerically. Our results are expressed in terms of asymptotic expansions at singular points of $z$ (light-cone momentum fraction carried by the quark-antiquark pair), which can not only give FFs results with very high precision at any value of $z$, but also provide fully analytical structure at these singularities. We find that the NLO corrections are significant, with K-factors larger than 2 in most regions. The NLO corrections may have important impact on heavy quarkonia (e.g. ${\eta }_c$ and $J/\psi$) production at the LHC.

    hep-phJHEP(2019)·42 citations
15. 15*

    Measuring Relic Abundance of Minimal Dark Matter at Hadron Colliders

    Qing-Hong Cao🇨🇳 · Ti Gong🇨🇳 · Ke-Pan Xie🇰🇷 · Zhen Zhang🇨🇳

    We consider the special case that the dark matter (DM) candidate is not detected in direct-detection programs when the experimental sensitivity reaches the neutrino flux background. In such circumstance the DM searches at the colliders impose constraints on the DM relic abundance if the DM candidate is a WIMPs type. Specifically, we consider the triplet (quintet and septet) DMs in the framework of minimal DM model and explore the potential of discovering the DM candidate in the mono-jet, mono-photon and vector boson fusion channels at the Large Hadron Collider and future 100~TeV hadron collider. If the DM candidate in such a scenario is discovered at the LHC, then additional DM candidates are needed to explain the observed relic abundance. On the other hand, null results in those DM searching programs at the colliders give rise to lower limits of DM relic abundance.

    hep-phhep-exSCPMA(2019)·8 citations
16. 16*

    Searching for weak singlet charged scalar at lepton colliders

    Qing-Hong Cao🇨🇳 · Gang Li🇹🇼 · Ke-Pan Xie🇰🇷 · Jue Zhang🇨🇳

    A weak singlet charged scalar exists in many new physics models beyond the Standard Model. The discovery potential of the singlet charged scalar is explored at future lepton colliders, e.g. the CEPC, ILC-350 and ILC-500. We demonstrate that one can discover the singlet charged scalar up to 118 GeV at the CEPC with an integrated luminosity of $5{\mathrm{ab}}^{-1}$. At the ILC-350 and the ILC-500 with an integrated luminosity of $1{\mathrm{ab}}^{-1}$ such a discovery limit can be further improved to 136 GeV and 160 GeV, respectively.

    hep-phhep-exPRD(2019)·7 citations
17. 17*

    Signature of Pseudo Nambu-Goldstone Higgs boson in its Decay

    Qing-Hong Cao🇨🇳 · Ling-Xiao Xu🇨🇳 · Bin Yan🇺🇸 · Shou-hua Zhu🇨🇳

    If the Higgs boson is a pseudo Nambu-Goldstone boson (PNGB), the $hZ\gamma$ contact interaction induced by the $\mathcal{O}(p^4)$ invariants of the non-linear sigma model is free from its nonlinearity effects. The process $h\to Z\gamma$ can be used to eliminate the universal effects of heavy particles, which can fake the nonlinearity effects of the PNGB Higgs boson in the process $h\to V^{\ast }V$ ($V=W^{\pm }$,\ $Z$). We demonstrate that the ratio of the signal strength of $h\to Z\gamma$ and $h\to V^{\ast }V$ is good to distinguish the signature of the PNGB Higgs boson from Higgs coupling deviations.

    hep-phhep-exPLB(2019)·32 citations
18. 18*

    Vacuum Stability of Asymptotically Safe Two Higgs Doublet Models

    Peter Schuh🇩🇪

    We study different types of Two Higgs Doublet Models (2HDMs) under the assumption that all quartic couplings' beta functions vanish simultaneously at the Planck scale. The Standard Model seems to display this property almost accidentally, because the Higgs boson mass is close to 125 GeV. This also ties closely into the question of whether the theory is stable or metastable. We investigate if such "fixed points" can exist in various ${\mathbb{Z}}_2$-symmetric 2HDM subclasses, and if the theories that meet these conditions are phenomenologically viable, as well as vacuum stable. We find that the fixed point condition drastically reduces the parameter space of 2HDM theories, but can be met. Fixed points can only exist in type II and type Y models, in regions of large tan$\beta$, and they are only compatible with all existing experimental bounds if the ${\mathbb{Z}}_2$-symmetry is at least softly broken, with a soft breaking parameter of at least $M_{12}$ $>$ 70 GeV (380 GeV) for type Y (type II) models. The allowed region falls into the alignment limit, with the mixing angle combination $|\alpha -\beta |\approx \frac{\pi }{2}$. While there are both vacuum-stable and vacuum-unstable solutions, only the vacuum-unstable ones really agree with Standard-Model-like CP-even Higgs boson mass values of 125 GeV. The vacuum-stable solutions favour slightly higher values. While scenarios of asymptotically safe 2HDM exist, they cannot improve over the Standard Model regarding the question of vacuum stability.

    hep-phEPJC(2019)·9 citations
19. 19*

    Bound state of heavy quarks using a general polynomial potential

    Hesham Mansour🇪🇬 · Ahmed Gamal🇪🇬

    In the present work, the mass spectra of the bound states of heavy quarks b and c quarks and the Bc meson are studied within the frame work of non relativistic Schrodinger equation. First, we solve Schrödinger's equation with a general polynomial potential by Nikiforov-Uvarov (NU) method. The energy eigenvalues for any L- value is presented for a special case of the potential. The results obtained are in good agreement with the experimental data and are better than previous theoretical studies.

    hep-phAdv.High Energy Phys.(2018)·17 citations
20. 20*

    A Global Likelihood for Precision Constraints and Flavour Anomalies

    Jason Aebischer🇩🇪 · Jacky Kumar🇨🇦 · Peter Stangl🇫🇷 · David M. Straub🇩🇪

    We present a global likelihood function in the space of dimension-six Wilson coefficients in the Standard Model Effective Field Theory (SMEFT). The likelihood includes contributions from flavour-changing neutral current B decays, lepton flavour universality tests in charged- and neutral-current B and K decays, meson-antimeson mixing observables in the K, B, and D systems, direct CP violation in K -> {\pi}{\pi}, charged lepton flavour violating B, tau, and muon decays, electroweak precision tests on the Z and W poles, the anomalous magnetic moments of the electron, muon, and tau, and several other precision observables, 265 in total. The Wilson coefficients can be specified at any scale, with the one-loop running above and below the electroweak scale automatically taken care of. The implementation of the likelihood function is based on the open source tools flavio and wilson as well as the open Wilson coefficient exchange format (WCxf) and can be installed as a Python package. It can serve as a basis either for model-independent fits or for testing dynamical models, in particular models built to address the anomalies in B physics. We discuss a number of example applications, reproducing results from the EFT and model building literature.

    hep-phEPJC(2019)·205 citations
21. 21*

    Emergence of Maximal Symmetry

    Csaba Csáki🇺🇸 · Teng Ma🇨🇳 · Jing Shu🇨🇳 · Jiang-Hao Yu🇨🇳

    An emergent global symmetry of the composite sector (called maximal symmetry) can soften the ultraviolet behavior of the Higgs potential and also significantly modify its structure. We explain the conditions for the emergence of maximal symmetry as well as its main consequences. We present two simple implementations and generalize both to N-site as well as full warped extra dimensional models. The gauge symmetry of these models enforces the emergence of maximal symmetry. The corresponding Higgs potentials have unique properties: one case minimizes the tuning while the other allows heavy top partners evading direct LHC bounds.

    hep-phhep-thPRL(2020)·22 citations
22. 22*

    Reverse Direct Detection: Cosmic Ray Scattering With Light Dark Matter

    Christopher V. Cappiello🇺🇸 · Kenny C. Y. Ng🇮🇱 · John F. Beacom🇺🇸

    Sub-GeV dark matter candidates are of increasing interest, because long-favored candidates such as GeV-scale WIMPs have not been detected. For low-mass dark matter, model-independent constraints are weak or nonexistent. We show that for such candidates, because the number density is high, cosmic ray propagation can be affected by elastic scattering with dark matter. We call this type of search `reverse direct detection,' because dark matter is the target and Standard Model particles are the beam. Using a simple propagation model for galactic cosmic rays, we calculate how dark matter affects cosmic ray spectra at Earth, and set new limits on the dark matter-proton and dark matter-electron cross sections. For protons, our limit is competitive with cosmological constraints, but is independent. For electrons, our limit covers masses not yet probed, and improves on cosmological constraints by one to two orders of magnitude. We comment on how future work can significantly improve the sensitivity of cosmic-ray probes of dark matter interactions.

    hep-phastro-ph.HEPRD(2019)·150 citations
23. 23*

    Decays of the f0(1370) scalar glueball candidate

    Ugo Gastaldi🇮🇹

    For a long time doubts have existed on the existence of the f0(1370) meson as an individual object distinct and separated from the sigma meson. Decays into two charged pions of the f0(1370) are the main source of an isolated structure localized between 1.2 and 1.5 GeV in the two charged pions mass spectrum measured in pp Central Exclusive Production (CEP) at 200 GeV at very low four momentum transfer squared ltl. These data confirm in the two charged pions decay channel the existence of the f0(1370) as an isolated well identified structure that was previously observed in K+K-, KsKs, 4 neutral pions, two neutral pions-two charged pions and 4 charged pions decays measured in pbar annihilations at rest. The decay branching ratios of f0(1370) into sigma-sigma, rho-rho, pion-pion, KKbar, eta-eta relative to pion-pion decays obtained in analysis of data of pbar annihilations at rest which treat separately f0(1370) and sigma are respectively 5.6, 3, 1, 1, 0.02. The decay and production properties of f0(1370) point to a large gg content. CEP interactions at very high energies favour production of 0++ and 2++ mesons. Selection of events with low ltl at both proton vertices suppresses 2++ structures. LHC runs dedicated to pp CEP measurements at low ltl could then provide a unique clean source of all the low energy scalars, cross check the pbar annihilation results and make it clear if and where scalar gluonium is resident and the nature (composition in terms of qqbar, qqqbarqbar, qqbar-qqbar and gg) of f0(500), f0(980), f0(1370), f0(1500) and f0(1710).

    hep-phNucl.Part.Phys.Proc.(2018)·0 citations
24. 24*

    Deeply virtual meson production on neutrons

    William Brooks🇨🇱 · Ivan Schmidt🇨🇱 · Marat Siddikov🇨🇱

    In this paper we analyze in detail how the measurements of exclusive electroproduction of mesons on neutrons would complement the studies of generalized parton distributions (GPDs) of the proton, providing independent experimental observables. Some of these processes on neutrons have very distinctive features, and thus we expect that measurements on liquid deuterium would allow to clearly distinguish them from similar processes on protons, giving a very clean probe of the GPD. In the case of charged meson production, all produced hadrons are charged, and for this reason we expect that the kinematics of this process could be easily reconstructed. We estimate the cross-sections in the kinematics of the Jefferson Laboratory experiments using current phenomenological GPD models.

    hep-phhep-exPRD(2018)·3 citations
25. 25*

    New Standard Model constraints on the scales and dimension of spacetime

    Andrea Addazi🇨🇳 · Gianluca Calcagni🇪🇸 · Antonino Marciano🇨🇳

    Using known estimates for the kaon--antikaon transitions, the mean lifetime of the muon and the mean lifetime of the tau, we place new and stronger constraints on the scales of the multi-fractional theories with weighted and $q$-derivatives. These scenarios reproduce a quantum-gravity regime where fields live on a continuous spacetime with a scale-dependent Hausdorff dimension. In the case with weighted derivatives, constraints from the muon lifetime are various orders of magnitude stronger than those from the tau lifetime and the kaon--antikaon transitions. The characteristic energy scale of the theory cannot be greater than $E_{\ast }>3\times 10^2\mathrm{TeV}$, and is tightened to $E_{\ast }>9\times 10^8\mathrm{TeV}$ for the typical value $\alpha =1/2$ of the fractional exponents in the spacetime measure. We also find an upper bound $d_{\mathrm{H}}<2.9$ on the spacetime Hausdorff dimension in the ultraviolet. In the case with $q$-derivatives, the strongest bound comes from the tau lifetime, but it is about 10 orders of magnitude weaker than for the theory with weighted derivatives.

    hep-phhep-thJHEP(2018)·8 citations
26. 26*

    On pion and kaon decay constants and chiral SU(3) extrapolations

    Xiao-Yu Guo🇩🇪 · Matthias F.M. Lutz🇩🇪

    We consider the dependence of the pion and kaon decay constants on the up, down and strange quark masses in QCD with strict isospin symmetry. The role of dynamical vector meson degrees of freedom is scrutinized in terms of an effective chiral Lagrangian for vector mesons. Applying a set of low-energy parameters as determined previously from QCD lattice data on the masses of the light vector mesons from PACS-CS, QCDSF-UKQCD and HSC we compute its implications on the pion and kaon decay constants for QCD lattice ensembles of HPQCD, CLS and ETMC. It is shown that with Gasser-Leutwyler L_4 and L_5 parameters fixed to the empirical decay constants an accurate reproduction of their values at unphysical quark masses as computed by HPQCD, CLS and ETMC is achieved. Results for the masses of the light vector meson, the \omega -\phi mixing angles and the quark mass ratios for the ensembles used by HPQCD, CLS and ETMC are discussed.

    ↳ hep-lathep-phNPA(2019)·4 citations
27. 27*

    The Science and Legacy of Richard Phillips Feynman

    Avinash Dhar🇮🇳 · Apoorva D. Patel🇮🇳 · Spenta R. Wadia🇮🇳

    This year is the 100th birth anniversary of Richard Philips Feynman. This article commemorates his scientific contributions and lasting legacy.

    ↳ physics.hist-phcond-mat.stat-mechgr-qchep-ph+1Physics News Vol 48, No 4, 2018, publishe…·1 citation
28. 28*

    Three-loop effective potential of general scalar theory via differential equations

    Bernd A. Kniehl🇩🇪 · Andrey F. Pikelner🇩🇪 · Oleg L. Veretin🇩🇪

    We consider the scalar sector of a general renormalizable theory and evaluate the effective potential through three loops analytically. We encounter three-loop vacuum bubble diagrams with up to two masses and six lines, which we solve using differential equations transformed into the favorable $ϵ$ form of dimensional regularization. The master integrals of the canonical basis thus obtained are expressed in terms of cyclotomic polylogarithms up to weight four. We also introduce an algorithm for the numerical evaluation of cyclotomic polylogarithms with multiple-precision arithmetic, which is implemented in the Mathematica package cyclogpl.m supplied here.

    ↳ hep-thhep-phNPB(2018)·2 citations
29. 29*

    The pressure distribution and shear forces inside the proton

    P. E. Shanahan🇺🇸 · W. Detmold🇺🇸

    The distributions of pressure and shear forces inside the proton are investigated using lattice Quantum Chromodynamics (LQCD) calculations of the energy momentum tensor, allowing the first model-independent determination of these fundamental aspects of proton structure. This is achieved by combining recent LQCD results for the gluon contributions to the energy momentum tensor with earlier calculations of the quark contributions. The utility of LQCD calculations in exploring, and supplementing, the assumptions in a recent extraction of the pressure distribution in the proton from deeply virtual Compton scattering experiments is also discussed. Based on this study, the target kinematics for experiments aiming to determine the pressure and shear distributions with greater precision at Thomas Jefferson National Accelerator Facility and a future Electron Ion Collider are investigated.

    ↳ nucl-thhep-lathep-phPRL(2019)·154 citations
30. 30*

    Possible detection of nonclassical primordial gravitational waves with Hanbury Brown - Twiss interferometry

    Sugumi Kanno🇯🇵 · Jiro Soda🇯🇵

    We consider possible detection of nonclassicality of primordial gravitational waves (PGWs) by applying Hanbury Brown - Twiss (HBT) interferometry to cosmology. We characterize the nonclassicality of PGWs in terms of sub-Poissonian statistics that can be measured by the HBT interferometry. We show that the presence of classical sources during inflation makes us possible to detect nonclassical PGWs with the HBT interferometry. We present two examples that realize the classical sources during inflation. It turns out that PGWs with frequencies higher than 10 kHz enable us to detect their nonclassicality.

    ↳ hep-thastro-ph.COgr-qchep-ph+1PRD(2019)·55 citations
31. 31*

    An asymptotically safe guide to quantum gravity and matter

    Astrid Eichhorn🇩🇪

    Asymptotic safety generalizes asymptotic freedom and could contribute to understanding physics beyond the Standard Model. It is a candidate scenario to provide an ultraviolet extension for the effective quantum field theory of gravity through an interacting fixed point of the Renormalization Group. Recently, asymptotic safety has been established in specific gauge-Yukawa models in four dimensions in perturbation theory, providing a starting point for asymptotically safe model building. Moreover, an asymptotically safe fixed point might even be induced in the Standard Model under the impact of quantum fluctuations of gravity in the vicinity of the Planck scale. This review contains an overview of the key concepts of asymptotic safety, its application to matter and gravity models, exploring potential phenomenological implications and highlighting open questions.

    ↳ hep-thgr-qchep-phFront.Astron.Space Sci.(2019)·303 citations
32. 32*

    Persistent homology analysis of deconfinement transition in effective Polyakov-line model

    Takehiro Hirakida🇯🇵 · Kouji Kashiwa🇯🇵 · Junpei Sugano🇯🇵 · Junichi Takahashi🇧🇷 · Hiroaki Kouno🇯🇵 · Masanobu Yahiro🇯🇵

    The persistent homology analysis is applied to the effective Polyakov-line model on a rectangular lattice to investigate the confinement-deconfinement nature. The lattice data are mapped onto the complex Polyakov-line plane without taking the spatial average and then the plane is divided into three domains. This study is based on previous studies for the clusters and the percolation properties in lattice QCD, but the mathematical method of the analyses are different. The spatial distribution of the data in the individual domain is analyzed by using the persistent homology to obtain information of the multiscale structure of center clusters. In the confined phase, the data in the three domains show the same topological tendency characterized by the birth and death times of the holes which are estimated via the filtration of the alpha complexes in the data space, but do not in the deconfined phase. By considering the configuration averaged ratio of the birth and death times of holes, we can construct the nonlocal order-parameter of the confinement-deconfinement transition from the multiscale topological properties of center clusters.

    ↳ hep-lathep-phInt.J.Mod.Phys.A(2020)·16 citations
33. 33*

    Second order splitting functions and infrared safe cross sections in $\mathcal{N}=4$ SYM theory

    Pulak Banerjee🇮🇳 · Amlan Chakraborty🇮🇳 · Prasanna K. Dhani🇮🇳 · V. Ravindran🇮🇳 · Satyajit Seth🇬🇧

    We report our findings on the perturbative structure of $\mathcal{N}=4$ supersymmetric Yang-Mills (SYM) theory in the infrared sector by computing inclusive scattering cross sections of on-shell particles. We use half-BPS, energy-momentum tensor and Konishi operators to produce singlet states in the scattering processes to probe the soft and the collinear properties of the cross sections. By appropriately defining the infrared safe observables, we obtain collinear splitting functions up to second order in the perturbation theory. The splitting functions and the infrared finite cross sections demonstrate several interesting connections with those in the perturbative QCD. We also determine the process independent soft distribution function up to third order in the perturbation theory and show that it is universal {\it i.e.} independent of the operators as well as the external states. Interestingly, the soft distribution function in $\mathcal{N}=4$ SYM theory matches exactly with the leading transcendental part of the corresponding one in the QCD. This enables us to predict the third order soft plus virtual cross section for the production of the on-shell singlet states.

    ↳ hep-thhep-phJHEP(2019)·6 citations
34. 34*

    Gravitational wave forms, polarizations, response functions and energy losses of triple systems in Einstein-Aether theory

    Kai Lin🇨🇳 · Xiang Zhao🇺🇸 · Chao Zhang🇺🇸 · Tan Liu🇨🇳 · Bin Wang🇨🇳 · Shaojun Zhang🇨🇳 · Xing Zhang🇨🇳 · Wen Zhao🇨🇳 · Tao Zhu🇨🇳 · Anzhong Wang🇺🇸

    Gravitationally bound hierarchies containing three or more components are very common in our Universe. In this paper we study {\em periodic} gravitational wave (GW) form, their polarizations, response function, its Fourier transform, and energy loss rate of a triple system through three different channels of radiation, the scalar, vector and tensor modes, in Einstein-aether theory of gravity. In the weak-field approximations and with the recently obtained constraints of the theory, we first analyze the energy loss rate of a binary system, and find that the dipole contributions from the scalar and vector modes could be of the order of $\mathcal{O}\left(c_{14}\right)\mathcal{O}{\left(G_{N}m/d\right)}^2$, where $c_{14}(\equiv c_1+c_4)$ is constrained to $c_{14}\lesssim \mathcal{O}\left(10^{-5}\right)$ by current observations, where $c_i$'s are the four coupling constants of the theory. On the other hand, the "strong-field" effects for a binary system of neutron stars are about six orders lower than that of GR. So, in this paper we ignore these "strong-field" effects and first develop the general formulas to the lowest post-Newtonian order, by taking the coupling of the aether field with matter into account. Within this approximation, we find that the scalar breather mode and the scalar longitudinal mode are all suppressed by a factor of $\mathcal{O}\left(c_{14}\right)$ with respect to the transverse-traceless modes ($h_{+}$ and $h_{\times }$), while the vectorial modes $(h_X$ and $h_Y$) are suppressed by a factor of $c_{13}\lesssim \mathcal{O}\left(10^{-15}\right)$. Applying the general formulas to a triple system with periodic orbits, we find that the corresponding GW form, response function, and its Fourier transform depend sensitively on both the configuration of the triple system and their orientations with respect to the detectors.

    ↳ astro-ph.GAastro-ph.COgr-qchep-ph+1PRD(2019)·40 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.