Tue·Oct 10, 2017Tuesday·October 10, 2017

1. 01*

   Spectroscopy and decays of the fully-heavy tetraquarks

   Muhammad Naeem Anwar🇨🇳 · Jacopo Ferretti🇨🇳 · Feng-Kun Guo🇨🇳 · Elena Santopinto🇮🇹 · Bing-Song Zou🇨🇳

   We discuss the possible existence of the fully-heavy tetraquarks. We calculate the ground-state energy of the $bb\bar{b}\bar{b}$ bound state, where $b$ stands for the bottom quark, in a nonrelativistic effective field theory framework with one-gluon-exchange (OGE) color Coulomb interaction, and in a relativized diquark model characterized by OGE plus a confining potential. Our analysis advocates the existence of uni-flavor heavy four-quark bound states. The ground state $bb\bar{b}\bar{b}$ tetraquark mass is predicted to be $(18.72\pm 0.02)$~GeV. Mass inequality relations among the lowest $QQ\bar{Q}\bar{Q}$ state, where $Q\in \{c,b\}$, and the corresponding heavy quarkonia are presented, which give the upper limit on the mass of ground state $QQ\bar{Q}\bar{Q}$. The possible decays of the lowest $bb\bar{b}\bar{b}$ are highlighted, which might provide useful references in the search for them in ongoing LHC experiments, and its width is estimated to be a few tens of MeV.

   hep-phhep-exnucl-thEPJC(2018)·175 citations
2. 02*

   Effective field theory for resonant wino dark matter

   Evan Johnson🇺🇸 · Hong Zhang🇺🇸 · Eric Braaten🇺🇸

   Enhancements in WIMP annihilation rates have been identified with a nonperturbative "Sommerfeld enhancement" arising from the exchange of light mediators. At certain critical values of the WIMP mass, the enhancement is increased dramatically due to a zero-energy resonance at the WIMP-pair threshold. For masses near these critical values, WIMP scattering processes are accurately described by an effective field theory where WIMPs have nonperturbative zero-range contact interactions. The effective field theory is controlled by a renormalization-group fixed point at which the WIMPs are degenerate in mass and their scattering length is infinite. If the WIMPs can exchange massless mediators, the resulting long-range interaction must also be treated nonperturbatively. We develop an effective field theory for SU(2)-triplet dark matter, which have short-range weak and long-range electromagnetic interactions. We refer to these dark matter particles as winos. The long-range Coulomb interaction between charged winos is resummed to all orders. The parameters of the effective field theory can be determined by matching wino-wino scattering amplitudes calculated by solving the Schrödinger equation with a potential describing exchange of electroweak gauge bosons. With Coulomb resummation, the effective field theory at leading order gives a good description of the low-energy two-body observables for winos.

   hep-ph0 citations
3. 03*

   Bernstein Polynomials based Probabilistic Interpretation of Quark Hadron Duality

   Evan Askanazi🇺🇸 · Simonetta Liuti🇺🇸

   It is now widely recognized that large Bjorken $x$ data play an important role in global analyses of Parton Distribution Functions (PDFs) even at collider energies, through perturbative QCD evolution. For values of the scale of the reaction, $Q^2$, in the multi-GeV region the structure functions at large $x$ present resonance structure. Notwithstanding, these data can be incorporated in the analyses by using quark-hadron duality or approximate scaling of the structure function data averaged over their resonance structure. Several averaging methods have been proposed using either the PDFs Mellin moments, or their truncated moments. We propose an alternative method using Bernstein polynomials integrals, or Bernstein moments. Bernstein moments render a smooth form of the structure function in the resonance region. Furthermore, being based on a different averaging criterion than the methods adopted so far, they provide a new framework for understanding the possible mechanisms giving origin to the phenomenon of quark-hadron duality.

   hep-ph0 citations
4. 04*

   Slepton Non-Universality in the Flavor-Effective MSSM

   M. Luisa López-Ibáñez🇪🇸 · Aurora Melis🇪🇸 · M. Jay Pérez🇪🇸 · Oscar Vives🇪🇸

   Supersymmetric theories supplemented by an underlying flavor-symmetry ${\mathcal{G}}_f$ provide a rich playground for model building aimed at explaining the flavor structure of the Standard Model. In the case where supersymmetry breaking is mediated by gravity, the soft-breaking Lagrangian typically exhibits large tree-level flavor violating effects, even if it stems from an ultraviolet flavor-conserving origin. Building on previous work, we continue our phenomenological analysis of these models with a particular emphasis on leptonic flavor observables. We consider three representative models which aim to explain the flavor structure of the lepton sector, with symmetry groups ${\mathcal{G}}_f=\Delta (27)$, $A_4,$ and $S_3$.

   hep-phJHEP(2017)·8 citations
5. 05*

   Predictions for production and decay of the pseudoscalar glueball from the Witten-Sakai-Sugimoto model

   Frederic Brünner🇦🇹 · Anton Rebhan🇦🇹

   The Witten-Sakai-Sugimoto model, a top-down gauge/gravity model of large-$N_c$ low-energy QCD based on type-IIA string theory and $N_c$ D4 branes with chiral quarks added by probe D8 branes, involves only one dimensionless parameter, the 't Hooft coupling at its cutoff (Kaluza-Klein) scale. Although this cutoff scale is around 1 GeV, the model has turned out to be surprisingly predictive also quantitatively, reproducing masses of vector and axial vector mesons, their decay rates, as well as the anomalous mass of the \eta' meson, all within 10-30% errors. Using it as a guide for glueball signatures, we have argued that it indicates that the meson $f_0(1710)$ may be a nearly pure glueball, with rather specific predictions for the still-to-be-measured 4\pi and \eta\eta' decays. Here we present our new predictions for the decay pattern of the (very narrow) pseudoscalar glueball, which is closely related to the U(1)${}_A$ problem that the model is in fact handling correctly.

   hep-phPoS(2017)·0 citations
6. 06*

   S-matrix analysis of the baryon electric charge correlation

   Pok Man Lo🇵🇱 · Bengt Friman🇩🇪 · Krzysztof Redlich🇵🇱 · Chihiro Sasaki🇵🇱

   We compute the correlation of the net baryon number with the electric charge (${\chi }_{BQ}$) for an interacting hadron gas using the S-matrix formulation of statistical mechanics. The observable ${\chi }_{BQ}$ is particularly sensitive to the details of the pion-nucleon interaction, which are consistently incorporated in the current scheme via the empirical scattering phase shifts. Comparing to the recent lattice QCD studies in the $(2+1)$-flavor system, we find that the natural implementation of interactions and the proper treatment of resonances in the S-matrix approach lead to an improved description of the lattice data over that obtained in the hadron resonance gas model.

   hep-phnucl-thPLB(2018)·59 citations
7. 07*

   Rare FCNC radiative leptonic decays $B\to \gamma {\ell }^{+}{\ell }^{-}$

   Dmitri Melikhov🇦🇹 · Anastasiia Kozachuk🇷🇺 · Nikolai Nikitin🇷🇺

   We present our recent results for long-distance QCD effects in the FCNC radiative leptonic decays $B\to \gamma {\ell }^{+}{\ell }^{-}$, $\ell =\{e,\mu \}$. One encounters here two distinct types of long-distance effects: those encoded in the $B\to \gamma$ transition form factors induced by the $b\to q$ quark currents, and those related to the charm-loop effects. We calculate the $B\to \gamma$ form factors in a broad range of the momentum transfers making use of the relativisitc dispersion approach based on the constituent quark picture which has proven to provide reliable predictions for many weak-transition form factors. Concerning the description of the charm-loop contributions, we point out two observations: First, the precise description of the charmonium resonances, in particular, the relative phases between $\psi$ and ${\psi }^{\prime }$, has impact on the differential distributions and on the forward-backward asymmetry, $A_{\mathrm{FB}}$, in a broad range of $q^2\ge 5$ GeV${}^2$. Second, the shape of $A_{\mathrm{FB}}$ in $B\to \gamma {\ell }^{+}{\ell }^{-}$ and in $B\to V{\ell }^{+}{\ell }^{-}$ ($V$ the vector meson) {\it in the $q^2$-region between $\psi$ and ${\psi }^{\prime }$} provides an unambiguous probe of the relative phases between $\psi$ and ${\psi }^{\prime }$. Fixing the latter will lead to a strong reduction of the theoretical uncertainties in $A_{\mathrm{FB}}$ at $q^2=5-9$ GeV${}^2$ where it has the sensitivity to physics beyond the SM.

   hep-phPoS(2017)·4 citations
8. 08*

   Average CsI neutron density distribution from COHERENT data

   M. Cadeddu🇮🇹 · C. Giunti🇮🇹 · Y.F. Li🇨🇳 · Y.Y. Zhang🇨🇳

   Using the coherent elastic neutrino-nucleus scattering data of the COHERENT experiment, we determine for the first time the average neutron rms radius of ${}^{133}\text{Cs}$ and ${}^{127}\text{I}$. We obtain the practically model-independent value $R_n=5.5{}_{-1.1}^{+0.9}\text{fm}$ using the symmetrized Fermi and Helm form factors. We also point out that the COHERENT data show a $2.3\sigma$ evidence of the nuclear structure suppression of the full coherence.

   hep-phhep-exnucl-exnucl-thPRL(2018)·160 citations
9. 09*

   Golden Probe of the di$-{\rm Y}$ Threshold

   Yi Chen · Roberto Vega-Morales

   Recent studies indicate that the ground state of a QCD four bottom quark system may form a resonance in the range $\sim 18-19$ GeV, near the di-${\rm Y}$ threshold, which may be observable at the LHC in the four lepton final state. These studies also predict a variety of possible resonances associated with the various excited states and allow for a number of possible spin and $CP$ quantum numbers. Of course, even if a resonance is observed in four leptons in the predicted mass range, it will be prudent to experimentally confirm its four bottom quark QCD nature or whether it is perhaps something more exotic. We initiate an investigation in this direction by exploring the ability of the \emph{normalized} fully differential decay width for decays to four leptons to probe the underlying nature of a putative resonance including $CP$ and tensor properties. We assume the first observed state is a spin-0 boson decaying to at least one on-shell ${\rm Y}$, but allow for decays to four leptons through ${\rm Y}{\rm Y},{\rm Y}\gamma$, and ${\rm Y}Z$ vector boson pairs. We consider a range of resonance masses around the di-${\rm Y}$ threshold and find excellent prospects at the LHC for establishing its $CP$ and tensor properties, perhaps not long after a discovery depending on (unknown) production cross sections and the exact resonance mass.

   hep-phhep-ex18 citations
10. 10*

    X(3872): propagating in a dense medium

    K. Azizi🇹🇷 · N. Er🇹🇷

    In cold nuclear matter, the shifts in the mass and current-meson coupling as well the vector self energy of the exotic $X(3872)$ are calculated using the diquark-antidiquark current within the framework of the in-medium two-point QCD sum rule. At the rest frame of the medium, the three momentum of the considered particle is fixed to remove the contributions of the particles with negative energy. In the calculations, we include the in-medium condensates of quark-quark, gluon-gluon and quark-gluon. It is observed that, the shift due to the nuclear matter is negative and is about $25\%$ when the saturation density is used. Such shift is considerably large and comparable with the nucleon' mass shift due to the nuclear medium. The negative shift in the current-meson coupling due to nuclear matter is approximately $10\%$. At the saturation density, the vector self energy of the exotic $X(3872)$ state is found to be ${\Sigma }_{\upsilon }=1.31$ GeV. It is shown that the mass, current-meson coupling and vector self energy of $X(3872)$ strongly depend on the density of cold nuclear matter.

    hep-phhep-exhep-latnucl-thNPB(2018)·29 citations
11. 11*

    Analysis of the scalar, axialvector, vector, tensor doubly charmed tetraquark states with QCD sum rules

    Zhi-Gang Wang🇨🇳 · Ze-Hui Yan🇨🇳

    In this article, we construct the axialvector-diquark-axialvector-antidiquark type currents to interpolate the scalar, axialvector, vector, tensor doubly charmed tetraquark states, and study them with QCD sum rules systematically by carrying out the operator product expansion up to the vacuum condensates of dimension 10 in a consistent way, the predicted masses can be confronted to the experimental data in the future. We can search for those doubly charmed tetraquark states in the Okubo-Zweig-Iizuka super-allowed strong decays to the charmed meson pairs.

    hep-phEPJC(2018)·66 citations
12. 12*

    Fine structures of azimuthal correlations of two gluons in the glasma

    Hengying Zhang🇨🇳 · Donghai Zhang🇨🇳 · Yeyin Zhao🇨🇳 · Mingmei Xu🇨🇳 · Xue Pan🇨🇳 · Yuanfang Wu🇨🇳

    We investigate the azimuthal correlations of the glasma in p-p collisions at $\sqrt{s_{\mathrm{NN}}}=7$ TeV by using the CGC formalism. As expected, the azimuthal correlations show two peaks at $\Delta \varphi =0$ and $\pi$ which represent collimation production in CGC. Beyond that, azimuthal correlations show fine structures, i.e. bumps or shoulders between the two peaks, when at least one gluon has small $x$. The structures are demonstrated to be associated with saturation momentum, and likely appear at transverse momentum around $2Q_{\mathrm{sp}}=1.8$ GeV$/$c.

    hep-phPRD(2018)·2 citations
13. 13*

    Derivation of Brown-Rho scaling from scale-chiral perturbation theory

    Yan-Ling Li🇨🇳 · Yong-Liang Ma🇨🇳

    The medium modified hadron properties are studied by using the scale-chiral perturbation theory $\chi$PT${}_{\sigma }$ in which the lightest scalar meson $f_0(500)$ is included as an explicit degree of freedom by regarding it as the Nambu-Goldstone boson of scale symmetry both spontaneously broken and explicitly broken by the QCD trace anomaly. We derive Brown-Rho scaling at the leading order of scale symmetry from $\chi$PT${}_{\sigma }$ and formulate how to make higher-order scale-chiral corrections going beyond the leading order of scale symmetry. By taking into account the intrinsic density dependence given by the dilaton condensate in the "bare" parameters of the Lagrangian, the medium modified hadron properties are investigated. Relying on available experimental information and certain reasonable assumptions, we arrive at the leading order scale symmetric effective theory that can be confronted with nature .

    hep-phnucl-th8 citations
14. 14*

    Gauged $L_{\mu }$-$L_{\tau }$ Model with an Inverse Seesaw Mechanism for Neutrino Masses

    Abhish Dev🇺🇸

    In this paper, we propose a $G_{L-R}\times U(1{)}_{L_{\mu }-L_{\tau }}$ gauge-symmetric model where $G_{L-R}$ is the left-right gauge symmetry and $L_i$ is the $i-$flavor lepton number. We use the spontaneous breaking (SSB) of $U(1{)}_{L_{\mu }-L_{\tau }}$ to explain two discrepancies in the standard model: muon anomalous magnetic moment and light neutrinos and its oscillations. The massive neutral gauge boson, $Z_{\mu \tau }$, arising from the SSB can provide additional contributions to the muon anomalous magnetic moment. In order to explain neutrino masses, we employ the low-energy inverse seesaw mechanism by adding three $G_{L-R}$ singlet fermions, $S_{e,\mu ,\tau }$. The light neutrino mass matrix from the inverse seesaw formula has a specific two-zero texture pattern referred in the literature as the Type-C two-zero texture due to the $U(1{)}_{L_{\mu }-L_{\tau }}$ symmetry. This allows us to predict the values of the CP-violating Dirac phase, Majorana phases, and the absolute value of light neutrino masses in terms of the precisely measured mixing angles and mass squared differences. The model accommodates a quasi-degenerate spectrum of neutrino masses with inverted ordering. The calculated best-fit value of ${\delta }_{CP}$ surprisingly matches with the current experimentally measured best-fit value of ${\delta }_{CP}$. At $1\sigma$, the measured value of ${\delta }_{CP}$ favors a ${\theta }_{23}>\pi /4$. At $1\sigma$, most of the parameter space is within the cosmological bound on the sum of neutrino mass and the bound on the effective Majorana mass from neutrinoless beta decay.

    hep-ph22 citations
15. 15*

    Rotating Dirac fermions in a magnetic field in 1+2,3 dimensions

    Yizhuang Liu🇺🇸 · Ismail Zahed🇺🇸

    We consider the effects of an external magnetic field on rotating fermions in 1+2,3 dimensions. The dual effect of a rotation parallel to the magnetic field causes a net increase in the fermionic density by centrifugation, which follows from the sinking of the particle lowest Landau level in the Dirac sea for free Dirac fermions. In 1+d = 2n dimensions, this effect is related to the chiral magnetic effect in 2n-2 dimensions. This phenomenon is discussed specifically for both weak and strong inter-fermion interactions in 1+2 dimensions. For QCD in 1+3 dimensions with Dirac quarks, we show that in the strongly coupled phase with spontaneously broken chiral symmetry, this mechanism reveals itself in the form of an induced pion condensation by centrifugation. We use this observation to show that this effect causes a shift in the chiral condensate in leading order, and to discuss the possibility for the formation of a novel pion super-fluid phase in present heavy ion collisions at collider energies.

    hep-phhep-thnucl-thPRD(2018)·25 citations
16. 16*

    Comments on "Vacuum Birefringence in a Rotating Magnetic Field" [S. L. Adler, J. Phys. A40 (2007) F143-F152] and "The Rotation of magnetic field does not impact vacuum birefringence" [S. Biswas and K. Melnikov, Phys. Rev. D75 (2007) 053003]

    P. Castelo Ferreira🇧🇷

    Compilation of 2 comments on S. L. Adler, "Vacuum Birefringence in a Rotating Magnetic Field", J.Phys. A40 (2007) F143-F152, hep-ph/0611267 and S. Biswas and K. Melnikov, "The Rotation of magnetic field does not impact vacuum birefringence", Phys. Rev. D75 (2007) 053003, hep-ph/0611345, hope it has some usefulness.

    hep-ph0 citations
17. 17*

    Differential Higgs production at N3LO beyond threshold

    Falko Dulat🇺🇸 · Bernhard Mistlberger🇨🇭 · Andrea Pelloni🇨🇭

    We present several key steps towards the computation of differential Higgs boson cross sections at N${}^3$LO in perturbative QCD. Specifically, we work in the framework of Higgs-differential cross sections that allows to compute precise predictions for realistic LHC observables. We demonstrate how to perform an expansion of the analytic N${}^3$LO coefficient functions around the production threshold of the Higgs boson. Our framework allows us to compute to arbitrarily high order in the threshold expansion and we explicitly obtain the first two expansion coefficients in analytic form. Furthermore, we assess the phenomenological viability of threshold expansions for differential distributions. In addition, we report on an interesting obstacle for the computation of N${}^3$LO corrections with LHAPDF parton distribution functions and our solution. We provide files containing the analytic expressions for the partonic cross sections together with the arXiv submission.

    hep-phJHEP(2018)·75 citations
18. 18*

    Sound waves in hadronic matter

    Grzegorz Wilk🇵🇱 · Zbigniew Wlodarczyk🇵🇱

    We argue that recent high energy CERN LHC experiments on transverse momenta distributions of produced particles provide us new, so far unnoticed and not fully appreciated, information on the underlying production processes. To this end we concentrate on the small (but persistent) log-periodic oscillations decorating the observed $p_T$ spectra and visible in the measured ratios $R={\sigma }_{data}\left(p_T\right)/{\sigma }_{fit}\left(p_T\right)$. Because such spectra are described by quasi-power-like formulas characterised by two parameters: the power index $n$ and scale parameter $T$ (usually identified with temperature $T$), the observed log-periodic behaviour of the ratios $R$ can originate either from suitable modifications of $n$ or $T$ (or both, but such a possibility is not discussed). In the first case $n$ becomes a complex number and this can be related to scale invariance in the system, in the second the scale parameter $T$ exhibits itself log-periodic oscillations which can be interpreted as the presence of some kind of sound waves forming in the collision system during the collision process, the wave number of which has a so-called self similar solution of the second kind. Because the first case was already widely discussed we concentrate on the second one and on its possible experimental consequences.

    hep-phEPJ Web Conf.(2018)·1 citation
19. 19*

    Exotic polyquark states and their properties in QCD

    Dmitri Melikhov🇦🇹

    We formulate rigorous criteria for selecting diagrams to be taken into account in the analysis of potential polyquark (tetra or penta) poles in QCD. The central point of these criteria is the requirement that the Feynman diagrams for the relevant Green functions contain four-quark (or, respectively, five-quark in the pentaquark case) intermediate states and the corresponding cuts. It is shown that some diagrams which "visually" seem to contain the four-quark cuts, turn out to be free of these singularities and therefore should not be taken into account when calculating the tetraquark properties. We then consider large-$N_c$ QCD which in many cases provide qualitatively correct picture of hadron properties and discuss in detail the tetraquark states. For the "direct" and the "recombination" four-point Green functions, which may potentially contain the tetraquark poles, we formulate large-$N_c$ consistency conditions which strongly restrict the behaviour of the tetraquark-to-ordinary meson transition amplitudes. In the end, these conditions allow us to obtain constraints on width of the potential tetraquark states at large $N_c$. We report that both flavor-exotic and cryptoexotic (i.e., flavor-nonexotic) tetraquarks, if the corresponding poles exist, have a width of order $O(1/N_c^2)$, i.e. they should be parametrically narrower compared to the ordinary $\bar{q}q$ mesons with a width of order $O(1/N_c)$. Moreover, for flavor-exotic states, the large-$N_c$ consistency conditions require two narrow flavor-exotic states, each of these states coupling dominantly to one specific meson-meson channel.

    hep-phEPJ Web Conf.(2017)·1 citation
20. 20*

    Broadening of the chiral critical region in a hydrodynamically expanding medium

    Christoph Herold🇹🇭 · Marcus Bleicher🇩🇪 · Marlene Nahrgang🇫🇷 · Jan Steinheimer🇩🇪 · Ayut Limphirat🇹🇭 · Chinorat Kobdaj🇹🇭 · Yupeng Yan🇹🇭

    We investigate higher cumulants of the sigma field as the chiral order parameter at the QCD phase transition. We derive a thermodynamic expression for the skewness and kurtosis from susceptibilities and use these to determine $S\sigma$ and $\kappa {\sigma }^2$ for the sigma field in equilibrium. In a next step, we study the behavior of these cumulants in both an equilibrated static medium and an expanding medium resembling the hydrodynamic stage of a heavy-ion collision. For the latter one, we find a significant broadening of the critical region.

    hep-phEPJA(2018)·15 citations
21. 21*

    Re-examining the $X(4630)$ resonance in the reaction $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$

    Ling-Yun Dai🇩🇪 · Johann Haidenbauer🇩🇪 · Ulf-G. Meißner🇩🇪

    The reaction $e^{+}{e}^{-}\to {\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ is investigated at energies close to the threshold with emphasis on the role played by the $X(4630)$ resonance. The interaction in the final ${\Lambda }_c^{+}{\bar{\Lambda }}_c^{-}$ system, constructed within chiral effective field theory and supplemented by a pole diagram that represents a bare $X(4630)$ resonance, is taken into account rigorously. The pole parameters of the $X(4630)$ are extracted and found to be compatible with the ones of the $X(4660)$ resonance that have been established in the reaction $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}\psi (2S)$. The actual result for the $X(4630)$ is $M=(4652.5\pm 3.4)$ MeV and $\Gamma =(62.6\pm 5.6)$ MeV. Predictions for the ${\Lambda }_c^{+}$ electromagnetic form factors in the timelike region are presented.

    hep-phnucl-thPRD(2017)·48 citations
22. 22*

    N-Jettiness Subtractions for $gg\to H$ at Subleading Power

    Ian Moult🇺🇸 · Lorena Rothen🇩🇪 · Iain W. Stewart🇺🇸 · Frank J. Tackmann🇩🇪 · Hua Xing Zhu🇨🇳

    $N$-jettiness subtractions provide a general approach for performing fully-differential next-to-next-to-leading order (NNLO) calculations. Since they are based on the physical resolution variable $N$-jettiness, ${\mathcal{T}}_N$, subleading power corrections in $\tau ={\mathcal{T}}_N/Q$, with $Q$ a hard interaction scale, can also be systematically computed. We study the structure of power corrections for $0$-jettiness, ${\mathcal{T}}_0$, for the $gg\to H$ process. Using the soft-collinear effective theory we analytically compute the leading power corrections ${\alpha }_s\tau \ln \tau$ and ${\alpha }_s^2\tau {\ln }^3\tau$ (finding partial agreement with a previous result in the literature), and perform a detailed numerical study of the power corrections in the $gg$, $gq$, and $q\bar{q}$ channels. This includes a numerical extraction of the ${\alpha }_s\tau$ and ${\alpha }_s^2\tau {\ln }^2\tau$ corrections, and a study of the dependence on the ${\mathcal{T}}_0$ definition. Including such power suppressed logarithms significantly reduces the size of missing power corrections, and hence improves the numerical efficiency of the subtraction method. Having a more detailed understanding of the power corrections for both $q\bar{q}$ and $gg$ initiated processes also provides insight into their universality, and hence their behavior in more complicated processes where they have not yet been analytically calculated.

    hep-phnucl-thPRD(2018)·97 citations
23. 23*

    $\mathbf{SO}(10)\times {\mathbf{S}}_4$ Grand Unified Theory of Flavour and Leptogenesis

    Francisco J. de Anda🇲🇽 · Stephen F. King🇬🇧 · Elena Perdomo🇬🇧

    We propose a Grand Unified Theory of Flavour, based on $SO(10)$ together with a non-Abelian discrete group $S_4$, under which the unified three quark and lepton 16-plets are unified into a single triplet $3^{\prime }$. The model involves a further discrete group ${\mathbb{Z}}_4^R\times {\mathbb{Z}}_4^3$ which controls the Higgs and flavon symmetry breaking sectors. The CSD2 flavon vacuum alignment is discussed, along with the GUT breaking potential and the doublet-triplet splitting, and proton decay is shown to be under control. The Yukawa matrices are derived in detail, from renormalisable diagrams, and neutrino masses emerge from the type I seesaw mechanism. A full numerical fit is performed with 15 input parameters generating 19 presently constrained observables, taking into account supersymmetry threshold corrections. The model predicts a normal neutrino mass ordering with a CP oscillation phase of $260^{\circ }$, an atmospheric angle in the first octant and neutrinoless double beta decay with $m_{\beta \beta }=11$ meV. We discuss $N_2$ leptogenesis, which fixes the second right-handed neutrino mass to be $M_2\simeq 2\times 10^{11}$ GeV, in the natural range predicted by the model.

    hep-phJHEP(2017)·30 citations
24. 24*

    Beyond Amplitudes' Positivity and the Fate of Massive Gravity

    Brando Bellazzini🇫🇷 · Francesco Riva🇨🇭 · Javi Serra🇨🇭 · Francesco Sgarlata🇮🇹

    We constrain effective field theories by going beyond the familiar positivity bounds that follow from unitarity, analyticity, and crossing symmetry of the scattering amplitudes. As interesting examples, we discuss the implications of the bounds for the Galileon and ghost-free massive gravity. The combination of our theoretical bounds with the experimental constraints on the graviton mass implies that the latter is either ruled out or unable to describe gravitational phenomena, let alone to consistently implement the Vainshtein mechanism, down to the relevant scales of fifth-force experiments, where general relativity has been successfully tested. We also show that the Galileon theory must contain symmetry-breaking terms that are at most one-loop suppressed compared to the symmetry-preserving ones. We comment as well on other interesting applications of our bounds.

    ↳ hep-thastro-ph.COgr-qchep-phPRL(2018)·161 citations
25. 25*

    Roper resonance -- solution to the fifty year puzzle

    Volker D. Burkert🇺🇸 · Craig D. Roberts🇺🇸

    For half a century, the Roper resonance has defied understanding. Discovered in 1963, it appears to be an exact copy of the proton except that its mass is 50% greater. The mass is the first problem: it is difficult to explain with any theoretical tool that can validly be used to study quantum chromodynamics [QCD]. In the last decade, a new challenge has appeared, viz. precise information on the proton-to-Roper electroproduction transition form factors, reaching $Q^2\approx 4.5$GeV${}^2$. This scale probes the domain within which hard valence-quark degrees-of-freedom could be expected to determine form factor behavior. Hence, with this new data the Roper resonance becomes a problem for strong-QCD [sQCD]. An explanation of how and where the Roper resonance fits into the emerging spectrum of hadrons cannot rest on a description of its mass alone. Instead, it must combine this with a detailed understanding of the Roper's structure and how that is revealed in the transition form factors. Furthermore, it must unify all this with a similarly complete picture of the proton. This is a prodigious task, but a ten-year international effort, drawing together experimentalists and theorists, has presented a solution to the puzzle. Namely, the Roper is at heart the proton's first radial excitation, consisting of a dressed-quark core augmented by a meson cloud that reduces the core mass by approximately 20% and materially alters its electroproduction form factors on $Q^2<2m_N^2$, where $m_N$ is the proton's mass. We describe the experimental motivations and developments which enabled electroproduction data to be procured within a domain that is unambiguously the purview of sQCD, thereby providing a real challenge and opportunity for modern theory; and survey the developments in reaction models and QCD theory that have enabled this conclusion to be drawn about the nature of the Roper resonance.

    ↳ nucl-exhep-lathep-phnucl-thRMP(2019)·162 citations
26. 26*

    Reducing the $H_0$ and ${\sigma }_8$ tensions with Dark Matter-neutrino interactions

    Eleonora Di Valentino🇬🇧 · Céline Bøehm🇬🇧 · Eric Hivon🇫🇷 · François R. Bouchet🇫🇷

    The introduction of Dark Matter-neutrino interactions modifies the Cosmic Microwave Background (CMB) angular power spectrum at all scales, thus affecting the reconstruction of the cosmological parameters. Such interactions can lead to a slight increase of the value of $H_0$ and a slight decrease of ${\sigma }_8$, which can help reduce somewhat the tension between the CMB and lensing or Cepheids datasets. Here we show that it is impossible to solve both tensions simultaneously. While the 2015 Planck temperature and low multipole polarisation data combined with the Cepheids datasets prefer large values of the Hubble rate (up to $H_0=72.1_{-1.7}^{+1.5}km/s/Mpc$, when $N_{\mathrm{eff}}$ is free to vary), the ${\sigma }_8$ parameter remains too large to reduce the ${\sigma }_8$ tension. Adding high multipole Planck polarization data does not help since this data shows a strong preference for low values of $H_0$, thus worsening current tensions, even though they also prefer smaller value of ${\sigma }_8$.

    ↳ astro-ph.COhep-phPRD(2018)·227 citations
27. 27*

    Constraints on inflation with LSS surveys: features in the primordial power spectrum

    Gonzalo A. Palma🇨🇱 · Domenico Sapone🇨🇱 · Spyros Sypsas🇨🇱

    We analyse the efficiency of future large scale structure surveys to unveil the presence of scale dependent features in the primordial spectrum --resulting from cosmic inflation-- imprinted in the distribution of galaxies. Features may appear as a consequence of non-trivial dynamics during cosmic inflation, in which one or more background quantities experienced small but rapid deviations from their characteristic slow-roll evolution. We consider two families of features: localized features and oscillatory extended features. To characterise them we employ various possible templates parametrising their scale dependence and provide forecasts on the constraints on these parametrisations for LSST like surveys. We perform a Fisher matrix analysis for three observables: cosmic microwave background (CMB), galaxy clustering and weak lensing. We find that the combined data set of these observables will be able to limit the presence of features down to levels that are more restrictive than current constraints coming from CMB observations only. In particular, we address the possibility of gaining information on currently known deviations from scale invariance inferred from CMB data, such as the feature appearing at the $\ell \sim 20$ multipole (which is the main contribution to the low-$\ell$ deficit) and a potential feature appearing at $\ell \sim 800$.

    ↳ astro-ph.COhep-phhep-thJCAP(2018)·43 citations
28. 28*

    Resurrecting Quadratic Inflation with a non-minimal coupling to gravity

    Tommi Tenkanen🇬🇧

    We study Quadratic Inflation with the inflaton field $\varphi$ coupled non-minimally to the curvature scalar $R$, so that the potential during inflation is of the form $V\propto m^2{\varphi }^2+\xi R{\varphi }^2$. We show that with a suitable choice of the non-minimal coupling strength, $\xi =\mathcal{O}(10^{-3})$, one can resurrect the success of the scenario when compared against the Planck and BICEP2/Keck Array data, and that in the region of the parameter space which is still allowed the model predicts values of the tensor-to-scalar ratio in the range $0.01\le r<0.12$, making it possible to either confirm the scenario or rule it out already by the current or near-future experiments, such as BICEP3 or LiteBIRD. However, we show that in this case the near-future observations are unlikely to be able to distinguish between the metric and Palatini formulations of gravity.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2017)·108 citations
29. 29*

    LHC results on tree-level beauty decays

    Mika Vesterinen (on behalf of the LHCb Collaboration)🇬🇧

    Tree-level $b$ decays play a critical role in characterising the quark flavour sector, and exposing possible effects of physics beyond the Standard Model. These proceedings cover recent results from the LHCb experiment on semileptonic $b$ baryon decays, $\mathcal{R}(D^{\ast -})$ using three-prong hadronic $\tau$ decays, $CP$ observables in $B^{-}\to D^{(\ast )}{h}^{-}$ decays, and an updated combination on the CKM angle $\gamma$.

    ↳ hep-exhep-phPoS(2017)·1 citation
30. 30*

    Nuclear Axial Currents from Scale-Chiral Effective Field Theory

    Yan-Ling Li🇨🇳 · Yong-Liang Ma🇨🇳 · Mannque Rho🇫🇷

    By incorporating hidden scale symmetry and hidden local symmetry in nuclear effective field theory, combined with double soft-pion theorem, we predict that the Gamow-Teller operator coming from the space component of the axial current should remain unaffected by the QCD vacuum change caused by baryonic density whereas the first forbidden beta transition operator coming from the time component should be strongly enhanced. While the latter has been confirmed since some time, the former is given a support by a powerful recent {\it ab initio} quantum Monte Carlo calculation in light nuclei, also confirming the old "chiral filter hypothesis." Formulated in terms of Fermi-liquid fixed point structure of strong-coupled nuclear interactions, we offer an extremely simple resolution to the long-standing puzzle of "quenched $g_A$", $g_A^{\mathrm{eff}}\approx 1$~\cite{quenched}, in nuclear Gamow-Teller beta transitions, giant Gamow-Teller resonances and double beta decays.

    ↳ nucl-thhep-phCPC(2018)·13 citations
31. 31*

    Radiative and EW Penguin $B$ Decays at Belle

    Akimasa Ishikawa🇯🇵

    We report on new results on $B\to K^{\ast }\gamma$ and recent studies on $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ and $B\to h\nu \bar{\nu }$ at Belle at KEKB accelerator. All the analyses used full data sample of 711~fb${}^{-1}$ taken on ${\rm Y}(4S)$ resonance.

    ↳ hep-exhep-phPoS(2017)·0 citations
32. 32*

    Probing Primordial Gravitational Waves: Ali CMB Polarization Telescope

    Hong Li🇨🇳 · Si-Yu Li🇨🇳 · Yang Liu🇨🇳 · Yong-Ping Li🇨🇳 · Yifu Cai🇨🇳 · Mingzhe Li🇨🇳 · Gong-Bo Zhao🇬🇧 · Cong-Zhan Liu🇨🇳 · Zheng-Wei Li🇨🇳 · He Xu🇨🇳 · Di Wu🇨🇳 · Yong-Jie Zhang🇨🇳 and 5 other authors

    In this paper, we will give a general introduction to the project of Ali CMB Polarization Telescope (AliCPT), which is a Sino-US joint project led by the Institute of High Energy Physics (IHEP) and has involved many different institutes in China. It is the first ground-based Cosmic Microwave Background (CMB) polarization experiment in China and an integral part of China's Gravitational Waves Program. The main scientific goal of AliCPT project is to probe the primordial gravitational waves (PGWs) originated from the very early Universe. The AliCPT project includes two stages. The first stage referred to as AliCPT-1, is to build a telescope in the Ali region of Tibet with an altitude of 5,250 meters. Once completed, it will be the worldwide highest ground-based CMB observatory and open a new window for probing PGWs in northern hemisphere. AliCPT-1 telescope is designed to have about 7,000 TES detectors at 90GHz and 150GHz. The second stage is to have a more sensitive telescope (AliCPT-2) with the number of detectors more than 20,000. Our simulations show that AliCPT will improve the current constraint on the tensor-to-scalar ratio $r$ by one order of magnitude with 3 years' observation. Besides the PGWs, the AliCPT will also enable a precise measurement on the CMB rotation angle and provide a precise test on the CPT symmetry. We show 3 years' observation will improve the current limit by two order of magnitude.

    ↳ astro-ph.COastro-ph.IMgr-qchep-ex+1Natl.Sci.Rev.(2019)·146 citations
33. 33*

    Effects of initial-state dynamics on collective flow within a coupled transport and viscous hydrodynamic approach

    Chandrodoy Chattopadhyay🇮🇳 · Rajeev S. Bhalerao🇮🇳 · Jean-Yves Ollitrault🇫🇷 · Subrata Pal🇮🇳

    We evaluate the effects of preequilibrium dynamics on observables in ultrarelativistic heavy-ion collisions. We simulate the initial nonequilibrium phase within A MultiPhase Transport (AMPT) model, while the subsequent near-equilibrium evolution is modeled using (2+1)-dimensional relativistic viscous hydrodynamics. We match the two stages of evolution carefully by calculating the full energy-momentum tensor from AMPT and using it as input for the hydrodynamic evolution. We find that when the preequilibrium evolution is taken into account, final-state observables are insensitive to the switching time from AMPT to hydrodynamics. Unlike some earlier treatments of preequilibrium dynamics, we do not find the initial shear viscous tensor to be large. With a shear viscosity to entropy density ratio of $0.12$, our model describes quantitatively a large set of experimental data on Pb+Pb collisions at the Large Hadron Collider(LHC) over a wide range of centrality: differential anisotropic flow $v_n(p_T)(n=2-6)$, event-plane correlations, correlation between $v_2$ and $v_3$, and cumulant ratio $v_2\{4\}/v_2\{2\}$.

    ↳ nucl-thhep-phnucl-exPRC(2018)·21 citations
34. 34*

    Probing the sign-changeable interaction between dark energy and dark matter with current observations

    Juan-Juan Guo🇨🇳 · Jing-Fei Zhang🇨🇳 · Yun-He Li🇨🇳 · Dong-Ze He🇨🇳 · Xin Zhang🇨🇳

    We consider the models of vacuum energy interacting with cold dark matter in this study, in which the coupling can change sigh during the cosmological evolution. We parameterize the running coupling $b$ by the form $b(a)=b_{0}a+b_e(1-a)$, where at the early-time the coupling is given by a constant $b_e$ and today the coupling is described by another constant $b_0$. We explore six specific models with (i) $Q(a)=b(a)H_0{\rho }_0$, (ii) $Q(a)=b(a)H_0{\rho }_{\mathrm{de}}$, (iii) $Q(a)=b(a)H_0{\rho }_{\mathrm{c}}$, (iv) $Q(a)=b(a)H{\rho }_0$, (v) $Q(a)=b(a)H{\rho }_{\mathrm{de}}$, and (vi) $Q(a)=b(a)H{\rho }_{\mathrm{c}}$. The current observational data sets we use to constrain the models include the JLA compilation of type Ia supernova data, the Planck 2015 distance priors data of cosmic microwave background observation, the baryon acoustic oscillations measurements, and the Hubble constant direct measurement. We find that, for all the models, we have $b_0<0$ and $b_e>0$ at around the 1$\sigma$ level, and $b_0$ and $b_e$ are in extremely strong anti-correlation. Our results show that the coupling changes sign during the evolution at about the 1$\sigma$ level, i.e., the energy transfer is from dark matter to dark energy when dark matter dominates the universe and the energy transfer is from dark energy to dark matter when dark energy dominates the universe.

    ↳ astro-ph.COgr-qchep-phSCPMA(2018)·51 citations
35. 35*

    A Method for Discriminating Between Dark Matter Models and MOND Modified Inertia via Galactic Rotation Curves

    Jonas Petersen🇩🇰 · Mads T. Frandsen🇩🇰

    Dark Matter (DM) and Modified Newtonian Dynamics (MOND) models of rotationally supported galaxies lead to curves with different geometries in $(g_N,g_{tot})$-space ($g2$-space). Here $g_{tot}$ is the total acceleration and $g_N$ is the acceleration as obtained from the baryonic matter via Newtonian dynamics. In MOND modified inertia (MI) models the curves in $g2$-space are closed with zero area and so curve segments at radii $r\ge r_N$ (large radii) and $r<r_N$ (small radii) coincide, where $r_N$ is the radius where $g_N$ is greatest. In DM models with cored density profiles where $g_{tot}$ is also zero at the galactic centre, the curves are again closed, but the area of the closed curves are in general non-zero because the curve segments at radii $r\ge r_N$ and $r<r_N$ do not coincide. Finally in DM models with cuspy density profiles such as the NFW profile where $g_{tot}$ is formally non-zero at the galactic origin the curves are open, and again the curve segments at radii $r\ge r_N$ and $r<r_N$ do not coincide. We develop a test of whether data at small and large radii coincide and investigate rotation curves from the SPARC database in order to discriminate between the above geometries. Due to loosely quantified systematic uncertainties we do not underline the result of the test, but instead conclude that the test illustrates the relevance of this type of analysis and demonstrate the ability to discriminate between the considered DM and MI models in this way.

    ↳ astro-ph.GAhep-phMNRAS(2020)·9 citations
36. 36*

    Measurement of Optical Orbital and Spin Angular Momentum: Implications for Photon Angular Momentum

    Elliot Leader🇬🇧

    The expression for the total angular momentum carried by a laser optical vortex beam, splits, in the paraxial approximation, into two terms which seem to represent orbital and spin angular momentum respectively. There are, however, two very different competing versions of the formula for the spin angular momentum, one based on the use of the Poynting vector, as in classical electrodynamics, the other related to the canonical expression for the angular momentum which occurs in Quantum Electrodynamic. I analyze the possibility that a sufficiently sensitive optical measurement could decide which of these corresponds to the actual physical angular momentum carried by the beam.

    ↳ physics.opticshep-phhep-thPLB(2018)·11 citations
37. 37*

    CMB spectral distortions as a novel way to probe the small-scale structure problems

    James Diacoumis🇦🇺 · Yvonne Wong🇦🇺

    In this work we consider CMB spectral distortions as a probe of dark matter microphysics in the early universe. We demonstrate that future experiments such as PRISM have the potential to distinguish between scenarios which offer solutions to the small-scale problems of CDM cosmology.

    ↳ astro-ph.COhep-ph2 citations
38. 38*

    Tests of Gravity with Future Space-Based Experiments

    Jeremy Sakstein🇺🇸

    Future space-based tests of relativistic gravitation-laser ranging to Phobos, accelerometers in orbit, and optical networks surrounding Earth-will constrain the theory of gravity with unprecedented precision by testing the inverse-square law, the strong and weak equivalence principles, and the deflection and time-delay of light by massive bodies. In this paper, we estimate the bounds that could be obtained on alternative gravity theories that use screening mechanisms to suppress deviations from general relativity in the solar system: chameleon, symmetron, and galileon models. We find that space-based tests of the parameterized post-Newtonian parameter $\gamma$ will constrain chameleon and symmetron theories to new levels in the solar system, and that tests of the inverse-square law using laser ranging to Phobos will provide the most stringent constraints on galileon theories to date. We end by discussing the potential for constraining these theories using upcoming tests of the weak equivalence principle, and conclude that further theoretical modeling is required in order to fully utilize the data.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2018)·69 citations
39. 39*

    What the Milky Way's Dwarfs tell us about the Galactic Center extended excess

    Ryan E. Keeley🇰🇷 · Kevork N. Abazajian🇺🇸 · Anna Kwa🇺🇸 · Nicholas L. Rodd🇺🇸 · Benjamin R. Safdi🇺🇸

    The Milky Way's Galactic Center harbors a gamma-ray excess that is a candidate signal of annihilating dark matter. Dwarf galaxies remain predominantly dark in their expected commensurate emission. In this work we quantify the degree of consistency between these two observations through a joint likelihood analysis. In doing so we incorporate Milky Way dark matter halo profile uncertainties, as well as an accounting of diffuse gamma-ray emission uncertainties in dark matter annihilation models for the Galactic Center Extended gamma-ray excess (GCE) detected by the Fermi Gamma-Ray Space Telescope. The preferred range of annihilation rates and masses expands when including these unknowns. Even so, using two recent determinations of the Milky Way halo's local density leave the GCE preferred region of single-channel dark matter annihilation models to be in strong tension with annihilation searches in combined dwarf galaxy analyses. A third, higher Milky Way density determination, alleviates this tension. Our joint likelihood analysis allows us to quantify this inconsistency. We provide a set of tools for testing dark matter annihilation models' consistency within this combined dataset. As an example, we test a representative inverse Compton sourced self-interacting dark matter model, which is consistent with both the GCE and dwarfs.

    ↳ astro-ph.HEastro-ph.COhep-phPRD(2018)·17 citations
40. 40*

    The Search for Beauty-fully Bound Tetraquarks Using Lattice Non-Relativistic QCD

    Ciaran Hughes🇺🇸 · Estia Eichten🇺🇸 · Christine T. H. Davies🇬🇧

    Motivated by multiple phenomenological considerations, we perform the first search for the existence of a $\bar{b}\bar{b}bb$ tetraquark bound state with a mass below the lowest non-interacting bottomonium-pair threshold using the first-principles lattice non-relativistic QCD methodology. We use a full $S$-wave colour/spin basis for the $\bar{b}\bar{b}bb$ operators in the three $0^{++}$, $1^{+-}$ and $2^{++}$ channels. We employ four gluon field ensembles at multiple lattice spacing values ranging from $a=0.06-0.12$ fm, all of which include $u$, $d$, $s$ and $c$ quarks in the sea, and one ensemble which has physical light-quark masses. Additionally, we perform novel exploratory work with the objective of highlighting any signal of a near threshold tetraquark, if it existed, by adding an auxiliary potential into the QCD interactions. With our results we find no evidence of a QCD bound tetraquark below the lowest non-interacting thresholds in the channels studied.

    ↳ hep-lathep-exhep-phPRD(2018)·127 citations
41. 41*

    Evolution of the Mean Jet Shape and Dijet Asymmetry Distribution of an Ensemble of Holographic Jets in Strongly Coupled Plasma

    Jasmine Brewer🇺🇸 · Krishna Rajagopal🇺🇸 · Andrey Sadofyev🇺🇸 · Wilke van der Schee🇺🇸

    Some of the most important probes of the quark-gluon plasma (QGP) produced in heavy ion collisions come from the analysis of how the shape and energy of jets are modified by passage through QGP. We model an ensemble of back-to-back dijets to gain a qualitative understanding of how the shapes of the individual jets and the asymmetry in the energy of the pairs of jets are modified by passage through an expanding droplet of strongly coupled plasma, as modeled in a holographic gauge theory. We do so by constructing an ensemble of strings in the gravitational description of the gauge theory. We model QCD jets in vacuum using strings whose endpoints move "downward" into the gravitational bulk spacetime with some fixed small angle that represents the opening angle (ratio of jet mass to jet energy) that the QCD jet would have in vacuum. Such strings must be moving through the gravitational bulk at (close to) the speed of light; they must be (close to) null. This condition does not specify the energy distribution along the string, meaning that it does not specify the shape of the jet being modeled. We study the dynamics of strings that are initially not null and show that strings with a wide range of initial conditions rapidly accelerate and become null and, as they do, develop a similar distribution of their energy density. We use this distribution of the energy density along the string, choose an ensemble of strings whose opening angles and energies are distributed as in perturbative QCD, and show that we can then fix one model parameter such that the mean jet shape in our ensemble matches that measured in p-p collisions reasonably well. We send our strings through the plasma, choosing the second model parameter to get a reasonable suppression in the number of jets, and study how the mean jet shape and the dijet asymmetry are modified, comparing both to data from LHC heavy ion collisions.

    ↳ nucl-thhep-phhep-thJHEP(2018)·51 citations
42. 42*

    Coulomb Artifacts and Breakdown of Perturbative Matching in Lattice NRQCD

    A. A. Penin🇨🇦 · A. Rayyan🇨🇦

    By studying an explicit analytical solution of the Coulomb problem on the lattice we demonstrate a breakdown of perturbative matching for the description of the Coulomb artifacts in lattice NRQCD, which leads to a large systematic error in the predictions for the heavy quarkonium spectrum. The breakdown is a result of a fine interplay between the short and long distance effects specific to the lattice regularization of NRQCD. We show how the problem can be solved within the Schrodinger matching procedure.

    ↳ hep-lathep-phJHEP(2017)·0 citations
43. 43*

    Simultaneous Production of Lepton Pairs at Ultra-peripheral Relativistic Heavy Ion Collisions

    Erkan Kurban🇹🇷 · Mehmet Cem Guclu🇹🇷

    We calculate the total cross sections and probabilities of electromagnetic productions of electron, muon and tauon pair productions simultaneously. At the Large Hadron Collider (LHC), the available electromagnetic energy is sufficient to produce all kind of leptons coherently. The masses of muon and tauon are large, so their Compton wavelengths are small enough to interact with the colliding nuclei. Therefore, the realistic nuclear form factors are included in the calculations of electromagnetic pair productions. The cross section calculations show that, at the LHC energies, the probabilities of simultaneous productions of all kind of leptons are increased significantly compare to the RHIC energies. Experimentally, observing this simultaneous production can give us important informations about the strong QED.

    ↳ nucl-thhep-phPRC(2017)·2 citations
44. 44*

    A unified model of supernova driven by magnetic monopoles

    Qiu-He Peng🇨🇳 · Jing-Jing Liu🇨🇳 · Chih-Kang Chou🇨🇳

    In this paper, we first discuss a series of important but puzzling physical mechanisms concerning the energy source, various kinds of core collapsed supernovae explosion mechanisms during central gravitational collapse in astrophysics. We also discuss the puzzle of possible association of $\gamma$-ray burst with gravitational wave perturbation, the heat source for the molten interior of the core of the earth and finally the puzzling problem of the cooling of white dwarfs. We then make use of the estimations for the space flux of magnetic monopoles (hereafter MMs) and nucleon decay induced by MMs (called the Rubakov-Callen(RC) effect) to obtain the luminosity due to the RC effect. In terms of the formula for this RC luminosity, we present a unified treatment for the heat source of the Earth's core, the energy source for the white dwarf interior, various kinds of core collapsed supernovae (Type II Supernova (SNII), Type Ib Supernova (SNIb), Type Ic Supernova (SNIc), Super luminous supernova (SLSN)), and the production mechanism for $\gamma$-ray burst. This unified model can also be used to reasonably explain the possible association of the short $\gamma$-ray burst detected by the Fermi $\gamma$-ray Burst Monitoring Satellite (GBM) with the LIGO gravitational wave event GW150914 in September 2015.

    ↳ astro-ph.HEhep-phAstrophys.Space Sci.(2017)·3 citations
45. 45*

    Viscous Warm Inflation: Hamilton-Jacobi formalism

    L. Akhtari🇮🇷 · A. Mohammadi🇮🇷 · K. Sayar🇮🇷 · Kh. Saaidi🇮🇷

    Using Hamilton-Jacobi formalism, The scenario of warm inflation with viscous pressure is considered. The formalism gives a way of computing the slow-rolling parameters without extra approximation, and it is well-known as a powerful method in cold inflation. The model is studied in detail for three different cases of dissipation and bulk viscous pressure coefficients. In the first case where both coefficients are taken as a constant, it is shown that the case could not portray warm inflationary scenario compatible with observational data even it is possible to restrict the model parameters. For other cases, the results shows that the model could properly predicts the perturbation parameters in which they stay in perfect agreement with Planck data. As a further argument, $r-n_s$ and ${\alpha }_s-n_s$ are drown that show the required result could stand in acceptable area expressing a compatibility with observational data.

    ↳ astro-ph.COgr-qchep-phAstropart.Phys.(2017)·27 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.