Fri·Nov 23, 2018Friday·November 23, 2018

1. 01*

   Nonperturbative structure of the ghost-gluon kernel

   A. C. Aguilar🇧🇷 · M. N. Ferreira🇧🇷 · C. T. Figueiredo🇧🇷 · J. Papavassiliou🇪🇸

   The ghost-gluon scattering kernel is a special correlation function that is intimately connected with two fundamental vertices of the gauge sector of QCD: the ghost-gluon vertex, which may be obtained from it through suitable contraction, and the three-gluon vertex, whose Slavnov-Taylor identity contains that kernel as one of its main ingredients. In this work we present a detailed nonperturbative study of the five form factors comprising it, using as starting point the `one-loop dressed' approximation of the dynamical equations governing their evolution. The analysis is carried out for arbitrary Euclidean momenta, and makes extensive use of the gluon propagator and the ghost dressing function, whose infrared behavior has been firmly established from a multitude of continuum studies and large-volume lattice simulations. In addition, special Ansätze are employed for the vertices entering in the relevant equations, and their impact on the results is scrutinized in detail. Quite interestingly, the veracity of the approximations employed may be quantitatively tested by appealing to an exact relation, which fixes the value of a special combination of the form factors under construction. The results obtained furnish the two form factors of the ghost-gluon vertex for arbitrary momenta, and, more importantly, pave the way towards the nonperturbative generalization of the Ball-Chiu construction for the longitudinal part of the three-gluon vertex.

   hep-phhep-lathep-thPRD(2019)·48 citations
2. 02*

   Speed of sound, breaking of conformal limit and instabilities in quark-gluon plasma at finite baryon density

   Z.V Khaidukov🇷🇺 · Yu.A.Simonov🇷🇺

   The properties of the quark-gluon plasma(QGP) in the presence of baryon chemical potential are studied using the Field Correlator Method(FCM). At low densities the QGP thermodynamics with the colormagnetic confinement and the Polyakov line interaction is in good agreement with lattice data,and the speed of sound satisfies $C_s^2\le \frac{1}{3}$,but in the intermediate range of densities the speed of sound displays a singular behaviour and one needs density modifications of the Polyakov line interaction to avoid instabilities. In particular for ${\mu }_q>0.5$ GeV there exists a region in the $(\mu ,T)$ plane where $C_s^2$ violates the conformal limit. This behaviour is strongly connected to the properties of the Polyakov loop and its density dependence.

   hep-ph7 citations
3. 03*

   Three body open flavor decays of higher charmonium and bottomonium

   Xin-Zhen Weng🇨🇳 · Li-Ye Xiao🇨🇳 · Wei-Zhen Deng🇨🇳 · Xiao-Lin Chen🇨🇳 · Shi-Lin Zhu🇨🇳

   In the present work, we study the OZI-allowed three body open flavor decay properties of higher vector charmonium and bottomonium states with an extended quark pair creation model. For the bottomonium system, we get that (i) the $BB\pi$ and $B^{\ast }{B}^{\ast }\pi$ partial decay widths of the ${\rm Y}(5S)$ state are consistent with the experiment, and the $B{B}^{\ast }\pi$ partial decay width of the ${\rm Y}(5S)$ state is smaller but very close to the Belle's experiment. Meanwhile, (ii) the $B{B}^{\ast }\pi$ and $B^{\ast }{B}^{\ast }\pi$ decay widths of ${\rm Y}(11020)$ can reachs $2\sim 3$ MeV. In addition, (iii) for the most of higher vector charmonium states, the partial decay widths of the $D{D}^{\ast }\pi$ and $D^{\ast }{D}^{\ast }\pi$ modes can reach up to several MeV, which may be observed in future experiments.

   hep-phhep-exhep-latPRD(2019)·9 citations
4. 04*

   Precision calculations in the MSSM Higgs-boson sector with FeynHiggs 2.14

   Henning Bahl🇩🇪 · Thomas Hahn🇩🇪 · Sven Heinemeyer🇪🇸 · Wolfgang Hollik🇩🇪 · Sebastian Paßehr🇫🇷 · Heidi Rzehak🇩🇰 · Georg Weiglein🇩🇪

   We present an overview of the status and recent developments of FeynHiggs (current version: 2.14.3) since version 2.12.2. The main purpose of FeynHiggs is the calculation of the Higgs-boson masses and other physical observables in the MSSM. For a precise prediction of the Higgs-boson masses for low and high SUSY scales, state-of-the-art fixed-order and effective-field-theory calculations are combined. We first discuss improvements of the fixed-order calculation, namely an optional $\overline{\text{DR}}$ renormalization of the stop sector and a renormalization of the Higgs sector ensuring the chosen input mass to be equivalent with the corresponding physical mass. Second, we describe improvements of the EFT calculation, i.e. an implementation of non-degenerate threshold corrections as well as an interpolation for complex parameters. Lastly, we highlight some improvements of the code structure easing future extensions of FeynHiggs to models beyond the MSSM.

   hep-phComput.Phys.Commun.(2020)·153 citations
5. 05*

   Probing Trans-electroweak First Order Phase Transitions from Gravitational Waves

   Andrea Addazi🇨🇳 · Antonino Marciano🇨🇳 · Roman Pasechnik🇸🇪

   We propose direct tests of very high energy first-order phase transitions, which are elusive to collider physics, deploying the gravitational waves measurements. We show that first-order phase transitions lying into a large window of critical temperatures, which is considerably larger than the electroweak energy scale, can be tested from aLIGO and Einstein Telescope. This provides the possibility to probe several inflationary mechanisms ending with the inflaton in a false minimum, and high-energy first order phase transitions that are due to new scalar bosons, beyond the Standard Model of particle physics. As an important example, we consider the axion monodromy inflationary scenario, and analyze the potential for its experimental verification, deploying the gravitational wave interferometers.

   hep-phgr-qcMDPI Physics(2019)·25 citations
6. 06*

   Exclusive $\rho$ and $J/\Psi$ photoproduction in ultraperipheral $pA$ collisions: Predictions of the gluon saturation models for the momentum transfer distributions

   V. P. Goncalves🇧🇷 · F. S. Navarra🇧🇷 · D. Spiering🇧🇷

   In this letter we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the $t$ - spectrum measured in exclusive $\rho$ and $J/\Psi$ photoproduction in $pA$ collisions at the LHC. We compute the differential cross sections considering two phenomenological models for the gluon saturation effects and present predictions for $pPb$ and $pCa$ collisions. Moreover, we compare our predictions with the recent preliminary CMS data for the exclusive $\rho$ photoproduction. We demonstrate that the gluon saturation models are able to describe the CMS data at small - $t$. On the other hand, the models underestimate the few data point at large -- $t$. Our results indicate that future measurements of the large -- $t$ region can be useful to probe the presence or absence of a dip in the $t$ -- spectrum and discriminate between the different approaches to the gluon saturation effects.

   hep-phhep-exnucl-thPLB(2019)·32 citations
7. 07*

   Properties of the decay $H\to \gamma \gamma$ using the approximate ${\alpha }_s^4$-corrections and the principle of maximum conformality

   Qing Yu🇨🇳 · Xing-Gang Wu🇨🇳 · Sheng-Quan Wang🇨🇳 · Xu-Dong Huang🇨🇳 · Jian-Ming Shen🇨🇳 · Jun Zeng🇨🇳

   The Higgs boson decay channel, $H\to \gamma \gamma$, is one of the most important channels for probing the properties of the Higgs boson. In the paper, we reanalyze its decay width by using the QCD corrections up to ${\alpha }_s^4$-order level. The principle of maximum conformality has been adopted to achieve a precise pQCD prediction without conventional renormalization scheme-and-scale ambiguities. By taking the Higgs mass as the one given by the ATLAS and CMS collaborations, i.e. $M_H=125.09\pm 0.21\pm 0.11$ GeV, we obtain $\Gamma (H\to \gamma \gamma ){|}_{\mathrm{LHC}}=9.364_{-0.075}^{+0.076}$ KeV.

   hep-phCPC(2019)·13 citations
8. 08*

   Scope of strongly self-interacting thermal WIMPs in a minimal $U(1{)}_D$ extension and its future prospects

   Rahool Kumar Barman🇮🇳 · Biplob Bhattacherjee🇮🇳 · Arindam Chatterjee🇮🇳 · Arghya Choudhury🇮🇳 · Aritra Gupta🇮🇳

   In this work we have considered a minimal extension of Standard Model by a local $U(1)$ gauge group in order to accommodate a stable (fermionic) Dark Matter (DM) candidate. We have focussed on parameter regions where DM possesses adequate self interaction, owing to the presence of a light scalar mediator (the dark Higgs), alleviating some of the tensions in the small-scale structures. We have studied the scenario in the light of a variety of data, mostly from dark matter direct searches, collider searches and flavour physics experiments, with an attempt to constrain the interactions of the standard model (SM) particles with the ones in the Dark Sector (DS). Assuming a small gauge kinetic mixing parameter, we find that for rather heavy DM %$\gtrsim \mathcal{O}(1-10)\mathrm{GeV}$%, the most stringent bound on the mixing angle of the Dark Higgs with the SM Higgs boson comes from dark matter direct detection experiments, while for lighter DM, LHC constraints become more relevant. Note that, due to the presence of very light mediators the usual realisation of direct detection constraints in terms of momentum independent cross sections had to be reevaluated for our scenario. In addition, we find that the smallness of the relevant portal couplings, as dictated by data, critically suppress the viability of DM production by the standard "freeze-out" mechanism in such simplified scenarios. In particular, the viable DM masses are $\lesssim \mathcal{O}(2)$ GeV $i.e.$ in the regions where direct detection limits tend to become weak. For heavier DM with large self-interactions, we hence conclude that non-thermal production mechanisms are favoured. Lastly, future collider reach of such a simplified scenario has also been studied in detail.

   hep-phJHEP(2020)·10 citations
9. 09*

   Prediction for the Cosmological Constant and Constraints on SUSY GUTS: Status Report for Resummed Quantum Gravity

   B.F.L. Ward (Baylor University, Waco, TX, USA)🇺🇸

   We give a status report on the theory of resummed quantum gravity. We recapitulate the use of our resummed quantum gravity approach to Einstein's general theory of relativity to estimate the value of the cosmological constant as ${\rho }_{\Lambda }=(0.0024\mathrm{eV}{)}^4$. The estimate is made in the context of the Planck scale cosmology formulation of Bonanno and Reuter. We discuss the constraints on susy GUT models that follow from the closeness of the estimate to experiment. Various consistency checks on the calculation are addressed and we use the Heisenberg uncertainty principle to remove a large part of the remaining uncertainty in our estimate of ${\rho }_{\Lambda }$.

   hep-phPoS(2019)·1 citation
10. 10*

    Lepton and Quark Masses and Mixing in a SUSY Model with Delta(384) and CP

    Claudia Hagedorn🇩🇰 · Johannes König🇩🇰

    We construct a supersymmetric model for leptons and quarks with the flavor symmetry Delta(384) and CP. The peculiar features of lepton and quark mixing are accomplished by the stepwise breaking of the flavor and CP symmetry. The correct description of lepton mixing angles requires two steps of symmetry breaking, where tri-bimaximal mixing arises after the first step. In the quark sector the Cabibbo angle theta_C equals sin pi/16 = 0.195 after the first step of symmetry breaking and it is brought into full agreement with experimental data after the second step. The two remaining quark mixing angles are generated after the third step of symmetry breaking. All three leptonic CP phases are predicted, sin delta^l = -0.936, |sin alpha|=|sin beta|=1/sqrt{2}. The amount of CP violation in the quark sector turns out to be maximal at the lowest order and is correctly accounted for, when higher order effects are included. Charged fermion masses are reproduced with the help of operators with different numbers of flavor (and CP) symmetry breaking fields. Light neutrino masses, arising from the type-I seesaw mechanism, can accommodate both mass orderings, normal and inverted. The vacuum alignment of the flavor (and CP) symmetry breaking fields is discussed at leading and at higher order.

    hep-phNPB(2020)·11 citations
11. 11*

    Color-allowed Bottom Baryon to Charmed Baryon non-leptonic Decays

    Chun-Khiang Chua🇹🇼

    We study color allowed ${\Lambda }_b\to {\Lambda }_c^{(\ast ,\ast \ast )}{M}^{-}$, ${\Xi }_b\to {\Xi }_c^{(\ast \ast )}{M}^{-}$ and ${\Omega }_b\to {\Omega }_c^{(\ast )}{M}^{-}$ decays with $M=\pi ,K,\rho ,K^{\ast },D,D_s,D^{\ast },D_s^{\ast },a_1$, ${\Lambda }_c^{(\ast ,\ast \ast )}={\Lambda }_c$, ${\Lambda }_c(2595)$, ${\Lambda }_c(2765)$, ${\Lambda }_c(2940)$, ${\Xi }_c^{(\ast \ast )}={\Xi }_c,{\Xi }_c(2790)$ and ${\Omega }_c^{(\ast )}={\Omega }_c,{\Omega }_c(3090)$, in this work. There are three types of transitions, namely ${\mathcal{B}}_b({\bar{3}}_{\mathbf{f}},1/2^{+})$ to ${\mathcal{B}}_c({\bar{3}}_{\mathbf{f}},1/2^{+})$, ${\mathcal{B}}_b(6_{\mathbf{f}},1/2^{+})$ to ${\mathcal{B}}_c(6_{\mathbf{f}},1/2^{+})$ and ${\mathcal{B}}_b({\bar{3}}_{\mathbf{f}},1/2^{+})$ to ${\mathcal{B}}_c({\bar{3}}_{\mathbf{f}},1/2^{-})$ transitions. The bottom baryon to charmed baryon form factors are calculated using the light-front quark model. Decay rates and up-down asymmetries are predicted using naïve factorization and can be checked experimentally. We find that in ${\mathcal{B}}_b\to {\mathcal{B}}_{c}P$ decays, rates in type~(ii) transition are smaller than those in type (i) transition, but similar to those in type (iii) transition, while in ${\mathcal{B}}_b\to {\mathcal{B}}_{c}V,{\mathcal{B}}_{c}A$ decays, rates in type~(ii) transition are much smaller than those in type (i) transition and are also smaller than those in type (iii) transition. For the up-down asymmetries, the signs are mostly negative, except for those in the type (ii) transition. All of these asymmetries are large in sizes. The study on these decay modes may shed light on the quantum numbers of some of the charmed baryons as the decays depend on the bottom baryon to charmed baryon form factors, which are sensitive to the configurations of the final state charmed baryons.

    hep-phhep-exPRD(2019)·42 citations
12. 12*

    Distinguishing Axion Models with IAXO

    Joerg Jaeckel🇩🇪 · Lennert J. Thormaehlen🇩🇪

    Helioscopes, such as the proposed International Axion Observatory (IAXO), have significant discovery potential for axions and axion-like particles. In this note, we argue that beyond discovery they can resolve details of the model. In particular, in the region suggested by stellar cooling anomalies, there is a good chance to measure the mass of the particle and separately its couplings to electrons and photons. This can give crucial information on the nature of the underlying model. To achieve this, energy resolved detectors and a setup with low energy threshold are needed.

    hep-phastro-ph.COJCAP(2019)·37 citations
13. 13*

    E-by-e jet suppression, anisotropy, medium response and hard-soft tomography

    Yayun He (CCNU)🇨🇳 · Shanshan Cao (WSU)🇺🇸 · Wei Chen (CCNU)🇨🇳 · Tan Luo (CCNU)🇨🇳 · Long-Gang Pang (UCB & LBNL)🇺🇸 · Xin-Nian Wang (CCNU & LBNL)🇨🇳

    The Linear Boltzmann Transport (LBT) model for jet propagation and interaction in quark-gluon plasma (QGP) has been used to study jet quenching in high-energy heavy-lion collisions. The suppression of single inclusive jet production, medium modification of $\gamma$-jet correlation, jet profiles and fragmentation functions as observed in experiments at Large Hadron Collider (LHC) can be described well by LBT in which jet-induced medium response is shown to play an essential role. In event-by-event simulations of jet quenching within LBT, jet azimuthal anisotropies are found to correlate linearly with the anisotropic flows of bulk hadrons from the underlying hydrodynamic events.

    ↳ nucl-thhep-phNPA(2019)·3 citations
14. 14*

    Nucleon Parton Distribution Amplitude: A scalar diquark picture

    Cédric Mezrag🇮🇹 · Jorge Segovia🇪🇸 · Minghui Ding🇮🇹 · Lei Chang🇨🇳 · Craig D. Roberts🇺🇸

    We report progress on the development of Perturbative Integral Representation Ansätze to compute the nucleon Faddeev Wave function, using an explicit quark-diquark picture. Our formalism is able to handle non-pointlike diquark and to mimic the strong, dynamical correlations observed when solving the Faddeev Equation. We then project the wave function in order to compute the leading-twist Parton Distribution Amplitude.

    ↳ nucl-thhep-phSpringer Proc.Phys.(2020)·2 citations
15. 15*

    Imprints of Primordial Non-Gaussianity on Gravitational Wave Spectrum

    Caner Unal🇨🇿

    Although Cosmic Microwave Background and Large Scale Structure probe the largest scales of our universe with ever increasing precision, our knowledge about the smaller scales is still very limited other than the bounds on Primordial Black Holes. We show that the statistical properties of the small scale quantum fluctuations can be probed via the stochastic gravitational wave background, which is induced as the scalar modes re-enter the horizon. We found that even if scalar curvature fluctuations have a subdominant non-Gaussian component, these non-Gaussian perturbations can source a dominant portion of the induced GWs. Moreover, the GWs sourced by non-Gaussian scalar fluctuations peaks at a higher frequency and this can result in distinctive observational signatures. We found that the sensitive next-generation-interferometers, which will/could reach ${\Omega }_{GW}{h}^2\sim 10^{-15}$ (such as PTA-SKA, LISA, DECIGO, BBO, CE, ET), can probe $f_{NL}\sim 0.5$ which is even better than the predictions of the next generation CMB experiments. If the induced GW background is detected, but not the signatures arising from the non-Gaussian component, $\zeta ={\zeta }_G+f_{\mathrm{NL}}{\zeta }_G^2$, this translates into bounds on $f_{\mathrm{NL}}$ depending on the amplitude and the width of the GW signal. If the induced GW background is not detected at all, this translates into bounds on scalar fluctuations. The results are independent from the fact that whether PBH are DM or completely negligible part of the current energy density.

    ↳ astro-ph.COgr-qchep-phhep-thPRD(2019)·222 citations
16. 16*

    A Fresh Look at the Calculation of Tunneling Actions in Multi-Field Potentials

    José Ramón Espinosa🇪🇸 · Thomas Konstandin🇩🇪

    The quantum decay of a metastable vacuum is exponentially suppressed by a tunneling action that can be calculated in the semi-classical approximation as the Euclidean action of a bounce that interpolates between the false and true phases. For multi-field potentials, finding the bounce is non-trivial due to its peculiar boundary conditions and the fact that the action at the bounce is not a minimum but merely a saddle point. Recently, an alternative tunneling action has been proposed that does not rely on Euclidean bounces and reproduces the standard result at its minimum. Here we generalize this new approach for several scalar fields and demonstrate how its use can significantly improve the numerical calculation of tunneling actions for multi-field potentials.

    ↳ hep-thgr-qchep-phJCAP(2019)·59 citations
17. 17*

    Beyond the Standard models of particle physics and cosmology

    Maxim Yu. Khlopov🇷🇺

    The modern Standard cosmological model of inflationary Unvierse and baryosynthesis deeply involves particle theory beyond the Standard model (BSM). Inevitably, models of BSM physics lead to cosmological scenarios beyond the Standard cosmological paradigm. Scenarios of dark atom cosmology in the context of puzzles of direct and indirect dark matter searches, of clusters of massive primordial black holes as the source of gravitational wave signals and of antimatter globular cluster as the source of cosmic antihelium are discussed.

    ↳ astro-ph.COastro-ph.HEhep-phBled Workshops Phys.(2018)·4 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.