Tue·Oct 1, 2019Tuesday·October 1, 2019

1. 01*

   Radiative quark $p_{\perp }$-broadening in a quark-gluon plasma at RHIC and LHC energies

   B.G. Zakharov🇷🇺

   We study the radiative correction to $p_{\perp }$-broadening of a fast quark in a quark-gluon plasma beyond the soft gluon approximation. We find that the radiative contribution to quark $⟨p_{\perp }^2⟩$ for RHIC and LHC conditions is negative.

   hep-phnucl-th0 citations
2. 02*

   Numerical approach to the semiclassical method of radiation emission for arbitrary electron spin and photon polarization

   T. N. Wistisen🇩🇪 · A. Di Piazza🇩🇪

   We show how the semiclassical formulas for radiation emission of Baier, Katkov and Strakhovenko for arbitrary initial and final spins of the electron and arbitrary polarization of the emitted photon can be rewritten in a form which numerically converges quickly. We directly compare the method in the case of a background plane wave with the result obtained by using the Volkov state solution of the Dirac equation, and confirm that we obtain the same result. We then investigate the interaction of a circularly polarized short laser pulse scattering with GeV electrons and see that the finite duration of the pulse leads to a lower transfer of circular polarization than that predicted by the known formulas in the monochromatic case. We also see how the transfer of circular polarization from the laser beam to the gamma ray beam is gradually deteriorated as the laser intensity increases, entering the nonlinear regime. However, this is shown to be recovered if the scattered photon beam is collimated to only allow for passage of photons emitted with angles smaller than $1/\gamma$ with respect to the initial electron direction, where $\gamma$ is the approximately constant Lorentz factor of the electron. The obtained formulas also allow us to answer questions regarding radiative polarization of the emitting particles. In this respect we briefly discuss an application of the present approach to the case of a bent crystal and high-energy positrons.

   hep-phphysics.plasm-phPRD(2019)·17 citations
3. 03*

   Hidden-charm and hidden-bottom molecular pentaquarks in chiral perturbation theory

   Bo Wang🇨🇳 · Lu Meng🇨🇳 · Shi-Lin Zhu🇨🇳

   The newly observed $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ at the LHCb experiment are very close to the ${\Sigma }_c\bar{D}$ and ${\Sigma }_c{\bar{D}}^{\ast }$ thresholds. In this work, we perform a systematic study and give a complete picture on the interactions between ${\Sigma }_c^{(\ast )}$ and ${\bar{D}}^{(\ast )}$ systems in the framework of heavy hadron chiral perturbation theory, where the short-range contact interaction, long-range one-pion-exchange contribution, and intermediate-range two-pion-exchange loop diagrams are all considered. We first investigate the three $P_c$ states without and with considering the ${\Lambda }_c$ contribution in the loop diagrams. It is difficult to simultaneously reproduce the three $P_c$s unless the effect of ${\Lambda }_c$ is included. The coupling between ${\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}$ and ${\Lambda }_c{\bar{D}}^{(\ast )}$ channels is crucial for the formation of these $P_c$s. Our calculation supports the $P_c(4312)$, $P_c(4440)$ and $P_c(4457)$ to be the $S$-wave hidden-charm $[{\Sigma }_c\bar{D}{]}_{J=1/2}^{I=1/2}$, $[{\Sigma }_c{\bar{D}}^{\ast }{]}_{J=1/2}^{I=1/2}$ and $[{\Sigma }_c{\bar{D}}^{\ast }{]}_{J=3/2}^{I=1/2}$ molecular pentaquarks, respectively. Our calculation disfavors the spin assignment $J^P={\frac{1}{2}}^{-}$ for $P_c(4457)$ and $J^P={\frac{3}{2}}^{-}$ for $P_c(4440)$, because the excessively enhanced spin-spin interaction is unreasonable in the present case. We obtain the complete mass spectra of the $[{\Sigma }_c^{(\ast )}{\bar{D}}^{(\ast )}{]}_J$ systems with the fixed low energy constants. Our result indicates the existence of $[{\Sigma }_c^{\ast }{\bar{D}}^{\ast }{]}_J(J=\frac{1}{2},\frac{3}{2},\frac{5}{2})$ hadronic molecules. The previously reported $P_c(4380)$ might be a deeper bound one. Additionally, we also study the hidden-bottom ${\Sigma }_b^{(\ast )}{B}^{(\ast )}$ systems, and predict seven bound molecular states, which could serve as a guidance for future experiments....

   hep-phhep-exhep-latJHEP(2019)·112 citations
4. 04*

   Novel method to reliably determine the photon helicity in $b\to s\gamma$

   Wei Wang🇨🇳 · Fu-Sheng Yu🇨🇳 · Zhen-Xing Zhao🇨🇳

   A sizable right-handed photon polarization in $b\to s\gamma$ is a clear signal for new physics. In this work we point out that the photon helicity in $b\to s\gamma$ can be unambiguously extracted by combining the measurements in $B\to K_1\gamma$ and the Cabibbo-favored $D\to K_1{e}^{+}\nu$ decay. We propose a ratio of up-down asymmetries in $D\to K_1{e}^{+}\nu$ to quantify the hadronic effects. { A method for measuring in experiment the involved partial decay widths in the ratio is discussed, and experimental facilities like BESIII, Belle-II and LHCb are likely to measure this ratio. We also give the angular distribution that is useful to extract the photon polarization in the presence of different kaon resonances. }

   hep-phhep-exPRL(2020)·16 citations
5. 05*

   Canonical interpretation of the $X(4140)$ state within the ${}^3{P}_0$ model

   Wei Hao🇨🇳 · Guan-Ying Wang🇨🇳 · En Wang🇨🇳 · Guan-Nan Li🇨🇳 · De-Min Li🇨🇳

   Recently, the LHCb Collaboration has confirmed the state $X(4140)$, with a mass $M=4146.5\pm 4.5_{-2.8}^{+4.6}$~MeV, and a much larger width $\Gamma =83\pm 21_{-14}^{+21}$~MeV than the previous experimental measurements, which has confused the understanding of its nature. We will investigate the possibility of the ${\chi }_{c1}(3P)$ interpretation for the $X(4140)$, considering the mass spectra predicted in the quark model, and the strong decay properties within the ${}^3{P}_0$ model. We also predict the strong decay properties of the charmonium states ${\chi }_{c0}(3P)$ and ${\chi }_{c2}(3P)$. Our results show that the $X(4140)$ state with the small width given in PDG can be explained as the charmonium state ${\chi }_{c1}(3P)$ in the ${}^3{P}_0$ model, and high precision measurement of the width of the $X(4140)$ is crucial to understand its nature.

   hep-phhep-exEPJC(2020)·27 citations
6. 06*

   Predictions for the Higgs boson mass measurement precision as a function of its transverse momentum up to 1 TeV for LHC and high luminosity LHC

   Philip Baringer🇺🇸 · Maxime Gouzevitch🇫🇷 · Anna Kropivnitskaya🇺🇸

   The question of naturalness of the Standard Model (SM) has been a hot topic since the discovery that the Higgs boson has a relatively light mass. It has been pointed out in the past that the mass of a scalar boson can be destabilized by loop corrections. Many theories have been proposed beyond the SM to address this problem. It is possible that such mechanisms contribute to the running of the Higgs mass with the energy scale. We present predictions for the precision of the Higgs mass measurement up to a Higgs boson transverse momentum of 1 TeV for the LHC in Run 3 with a luminosity of 300 fb-1, and the high luminosity LHC with a luminosity of 3000 fb-1. Predictions are generated with Madgraph5, Pythia8 and Delphes based on the CMS detector resolution.

   hep-phhep-ex0 citations
7. 07*

   Local $SU(2)\times U(1)$ Quark Flavor Symmetry in the RS Bulk

   George N. Wojcik🇺🇸 · Thomas G. Rizzo🇺🇸

   We propose a model of quark flavor based on an additional $SU(2)\times U(1)$ local symmetry in a warped extra dimensional bulk. In contrast to other works, we break the additional gauge symmetry in the bulk via two complex scalars which acquire bulk vevs, rather than relying on brane-localized symmetry breaking. A gauge-covariant Kaluza-Klein decomposition of a theory with a bulk spontaneously broken gauge symmetry is performed, and exact expressions for the bulk profiles of all physical particles in such systems are given. The SM quark masses and mixings are then recreated using gauge-covariant bulk quark mass terms and Yukawa-like couplings to the new bulk scalars. A numerical sampling of points in the model parameter space that recreate the quark masses and mixings is performed at a KK scale of $M_{KK}=5$ TeV. We then compute the $\Delta F=2$ 4-quark operators arising from our new flavor gauge bosons and scalars, and those arising from Kaluza-Klein modes of SM gauge bosons. By decoupling one of our bulk scalar fields to all quark fields except the right-handed up-like sector, we find that it is possible to greatly suppress tree-level contributions to the highly constrained Kaon mixing parameters. Instead, the dominant constraints on the model emerge from neutral $B_d$ and $D$ meson mixing. These constraints are explored with our numerical sampling of the model parameter space, and the specific contribution of the new flavor gauge bosons and scalars is discussed. We find that for a significant range of realistic flavor gauge couplings, the new gauge bosons compete with the normally dominant gluon flavor-changing currents, but flavor-changing operators emerging from the bulk scalar fields are highly suppressed. Finally, we briefly comment on flavor constraints that are independent of the flavor gauge sector arising from the $Z{\bar{b}}_L{b}_L$ coupling and rare top decays.

   hep-phJHEP(2020)·3 citations
8. 08*

   A new description of transverse momentum spectra of identified particles produced in proton-proton collisions at high energies

   Pei-Pin Yang🇨🇳 · Fu-Hu Liu🇨🇳 · Raghunath Sahoo🇮🇳

   The transverse momentum spectra of identified particles produced in high energy proton-proton ($p+p$) collisions are empirically described by a new method with the framework of participant quark model or the multisource model at the quark level, in which the source itself is exactly the participant quark. Each participant (constituent) quark contributes to the transverse momentum spectrum, which is described by the TP-like function, a revised Tsallis--Pareto-type function. The transverse momentum spectrum of the hadron is the convolution of two or more TP-like functions. For a lepton, the transverse momentum spectrum is the convolution of two TP-like functions due to two participant quarks, e.g. projectile and target quarks, taking part in the collisions. A discussed theoretical approach seems to describe the $p+p$ collisions data at center-of-mass energy $\sqrt{s}=200$ GeV, 2.76 TeV, and 13 TeV very well.

   hep-phhep-exnucl-exnucl-thAdv.High Energy Phys.(2020)·12 citations
9. 09*

   Gamma-ray signals from multicomponent scalar dark matter decays

   Avirup Ghosh🇮🇳 · Alejandro Ibarra🇩🇪 · Tanmoy Mondal🇰🇷 · Biswarup Mukhopadhyaya🇮🇳

   Within a multicomponent dark matter scenario, novel gamma-ray signals may arise from the decay of the heavier dark matter component into the lighter. For a scalar dark sector of this kind, the decay ${\varphi }_2\to {\varphi }_1\gamma$ is forbidden by the conservation of angular momentum, but the decay ${\varphi }_2\to {\varphi }_1\gamma \gamma$ can have a sizable or even dominant branching ratio. In this paper we present a detailed study of this decay channel. We determine the width and photon energy spectrum generated in the decay, employing an effective theory approach, and in UV complete models where the scalar dark matter components interact with heavy or light fermions. We also calculate limits on the inverse width from current data of the isotropic diffuse photon flux, both for a hierarchical and a degenerate dark matter spectrum. Finally, we briefly comment on the prospects of observing the diphoton signal from sneutrino decay in the minimal supersymmetric standard model extended with right-handed neutrino superfields ($\tilde{\nu }$MSSM).

   hep-phJCAP(2020)·11 citations
10. 10*

    Cosmological Dependence of Non-resonantly Produced Sterile Neutrinos

    Graciela B. Gelmini🇺🇸 · Philip Lu🇺🇸 · Volodymyr Takhistov🇺🇸

    We discuss how a laboratory detection of a sterile neutrino not only would constitute a fundamental discovery of a new particle, but could also provide an indication of the evolution of the Universe before Big-Bang Nucleosynthesis (BBN), a fundamental discovery in cosmology. These "visible" sterile neutrinos could be detected in experiments such as KATRIN/TRISTAN and HUNTER in the keV mass range and PTOLEMY, KATRIN and reactor neutrino experiments in the eV mass range. Standard assumptions are usually made to compute the relic abundance and momentum distribution of particles produced before the temperature of the Universe was 5 MeV, an epoch from which there are no observed remnants thus far. However, non-standard pre-BBN cosmologies based on other assumptions that are equally in agreement with all existing data can arise in some theoretical models. We revisit the production of 0.01 eV to 1 MeV sterile neutrinos via non-resonant active-sterile flavor oscillations in several pre-BBN cosmologies. We give general equations for models in which the expansion of the Universe is parametrized by its amplitude and temperature power and where entropy is conserved, which include kination and scalar tensor models as special cases.

    hep-phastro-ph.COhep-exJCAP(2019)·51 citations
11. 11*

    Schwinger pair production correction in thermal system

    Y. L. Wang🇨🇳 · H. B. Sang🇨🇳 · B. S. Xie🇨🇳

    In this paper, we give formal results of Schwinger pair production correction in thermal systems with external background field by using the evolution operator method of thermo field dynamics, where especially tree level correction of thermal photons is considered with linear response approaches by an effective mass shift. We consider initial systems in two types of vacuums as zero temperature and thermal vacuum, respectively, with correction of thermal photons is or not included. As an example we give results of these corrections to pair production for a constant external background electric field.

    hep-phquant-phPRD(2019)·3 citations
12. 12*

    Molecular ${\Xi }_{bc}$ states from meson-baryon interaction

    Qi-Xin Yu🇨🇳 · J. M. Dias🇨🇳 · Wei-Hong Liang🇨🇳 · E. Oset🇪🇸

    We have studied the meson-baryon interaction in coupled channels with the same quantum numbers of ${\Xi }_{bc}$. The interaction is attractive in some channels and of sufficient intensity to lead to bound states or resonances. We use a model describing the meson-baryon interaction based on an extrapolation of the local hidden gauge approach to the heavy sector, which has been successfully used in predicting ${\Omega }_c$ and hidden charm states. We obtain many states, some of them narrow or with zero width, as a consequence of the interaction, which qualify as molecular states in those channels. The success in related sectors of the picture used should encourage the experimental search for such states.

    hep-phEPJC(2019)·26 citations
13. 13*

    Glauber model for small system using anisotropic and inhomogeneous density profile of proton

    Suman Deb🇮🇳 · Golam Sarwar🇮🇳 · Dhananjaya Thakur🇮🇳 · Pavish S. · Raghunath Sahoo🇮🇳 · Jan-e Alam🇮🇳

    Recent studies reveal that at high energies, collisions of small system like $p+p$ gives signatures similar to that widely observed in heavy ion collisions hinting towards a possibility of forming a medium with collective behaviour. With this motivation, we have used the Glauber model, which is traditionally applied to heavy ion collisions, in small system using anisotropic and inhomogeneous density profile of proton and found that the proposed model reproduces the charged particle multiplicity distribution of $p+p$ collisions at LHC energies very well. Collision geometric properties like mean impact parameter, mean number of binary collisions ($⟨N_{coll}⟩$) and mean number of participants ($⟨N_{part}⟩$) at different multiplicities are determined. Having estimated $⟨N_{coll}⟩$, we have calculated nuclear modification-like factor ($R_{HL}$) in $p+p$ collisions. We also estimated eccentricity and elliptic flow as a function of charged particle multiplicity using the linear response to initial geometry.

    hep-phnucl-exnucl-thPRD(2020)·10 citations
14. 14*

    Measuring Entangled Neutrino States in a Toy Model QFT

    Emilio Ciuffoli🇨🇳 · Jarah Evslin🇨🇳 · Hosam Mohammed🇨🇳

    Localized wave packet treatments of neutrino oscillations by various groups lead to mutually inconsistent predictions. The neutrino wave packet description arises as an approximate substitute for the evolution of an entangled state which is not localized. The disagreements arise from qualitative differences in the framework which are not specific to electroweak interactions, and so have analogues in simpler models. Therefore in this note we introduce a toy model which allows one to explicitly test these predictions while consistently keeping track of the entanglement of the neutrinos and the source particles. Our study is robust as we use only the Schrodinger picture evolution equations on the entangled state, which are solved explicitly without recourse to the wave packet approximation.

    hep-phNPB(2020)·5 citations
15. 15*

    Low-energy axial-vector transitions from decuplet to octet baryons

    Måns Holmberg🇸🇪 · Stefan Leupold🇸🇪

    Axial-vector transitions of decuplet to octet baryons are parametrized at low energies guided by a complete and minimal chiral Lagrangian up to next-to-leading order. It is pointed out that beyond the well-known leading-order term, there is only one contribution at next-to-leading order. This contribution is flavor symmetric. Therefore the corresponding low-energy constant can be determined in any strangeness sector. As functions of this low-energy constant, we calculate the decay widths and Dalitz distributions for the decays of decuplet baryons to octet baryons, pions, and photons and for the weak decay of the Omega baryon to a cascade baryon, an electron, and an anti-neutrino.

    hep-phPRD(2019)·8 citations
16. 16*

    Study of Nonstandard Interactions in Rare Decays of Hyprons with Missing Energy

    Abrar Ahmed🇵🇰 · Shakeel Mahmood🇵🇰 · Farida Tahir🇵🇰 · Maimoona Razzaq🇵🇰

    We study rare decays of hyperons involving di-neutrinos in the final state in the standard model and compare them with other models. It is claimed that the branching ratio calculated in this article are 2 times the values of 331 model and exceptionally large than the previously calculated values. We explore the nonstandard neutrino interactions (NSI) and constrain NSIs free parameter with these decays. We obtain stringent bounds on of O(0.01). We show that branching ratios (Br) could be in the range of BES III if constraints are O(0.3).

    hep-phInt.J.Mod.Phys.A(2022)·2 citations
17. 17*

    Decay properties of $P$-wave heavy baryons accompanied by vector mesons within light-cone sum rules

    Hui-Min Yang🇨🇳 · Hua-Xing Chen🇨🇳 · Er-Liang Cui🇨🇳 · Atsushi Hosaka🇯🇵 · Qiang Mao🇨🇳

    We use the method of light-cone sum rules to study decay properties of $P$-wave bottom baryons belonging to the $SU(3)$ flavor $6_F$ representation. In Ref.~\cite{Cui:2019dzj} we have studied their mass spectrum and pionic decays, and found that the ${\Sigma }_b(6097)$ and ${\Xi }_b(6227)$ can be well interpreted as $P$-wave bottom baryons of $J^P=3/2^{-}$. In this paper we further study their decays into ground-state bottom baryons and vector mesons. We propose to search for a new state ${\Xi }_b({5/2}^{-})$, that is the $J^P=5/2^{-}$ partner state of the ${\Xi }_b(6227)$, in the ${\Xi }_b({5/2}^{-})\to {\Xi }_b^{\ast }\rho \to {\Xi }_b^{\ast }\pi \pi$ decay process. Its mass is $12\pm 5$~MeV larger than that of the ${\Xi }_b(6227)$.

    hep-phhep-exhep-latEPJC(2020)·38 citations
18. 18*

    On analytical solutions of the DIS structure functions in the framework of GLR-MQ-ZRS equation

    Madhurjya Lalung🇮🇳 · Pragyan Phukan🇮🇳 · Jayanta Kumar Sarma🇮🇳

    We computed the deep inelastic scattering (DIS) structure functions $F_2(x,Q^2)$ and $F_L(x,Q^2)$ in the framework of Gribov-Levin-Ryskin-Mueller-Qiu, Zhu-Ruan-Shen (GLR-MQ-ZRS) equation. Both $x$ and $Q^2$ evolutions of the structure functions are studied in the kinematic range of $10^{-6}\le x\le 10^{-2}$ and $5\le Q^2\le 100,Ge{V}^2$ respectively. we have suggested analytical solutions to the structure functions, our results are inspired by Regge like behaviour of gluons at small-x. The solutions of structure functions are obtained for two particular cases: (i) treating the strong coupling constant ${\alpha }_s$ as an arbitrary constant, and (ii) considering the $Q^2$ dependency of ${\alpha }_s$. Our predicted results are in good agreement with the latest available high precision HERA data.

    hep-ph1 citation
19. 19*

    Renormalon-based resummation for QCD observables

    Gorazd Cvetic🇨🇱

    A method of evaluation of spacelike QCD observables $\mathcal{D}(Q^2)$ is presented, motivated by the renormalon structure of these quantities.

    hep-phNucl.Part.Phys.Proc.(2020)·5 citations
20. 20*

    Constraining top-quark couplings combining top-quark and $\mathbf{B}$ decay observables

    Stefan Bißmann🇩🇪 · Johannes Erdmann🇩🇪 · Cornelius Grunwald🇩🇪 · Gudrun Hiller🇩🇪 · Kevin Kröninger🇩🇪

    We present a first, consistent combination of measurements from top-quark and $B$ physics to constrain top-quark properties within the Standard Model Effective Field Theory (SMEFT). We demonstrate the feasibility and benefits of this approach and detail the ingredients required for a proper combination of observables from different energy scales. Specifically, we employ measurements of the $t\bar{t}\gamma$ cross section together with measurements of the $\bar{B}\to X_s\gamma$ branching fraction to test the Standard Model and look for new physics contributions to the couplings of the top quark to the gauge bosons within SMEFT. We perform fits of three Wilson coefficients of dimension-six operators considering only the individual observables as well as their combination to demonstrate how the complementarity between top-quark and $B$ physics observables allows to resolve ambiguities and significantly improves the constraints on the Wilson coefficients. No significant deviation from the Standard Model is found with present data.

    hep-phEPJC(2020)·73 citations
21. 21*

    Fluctuating vector mesons in analytically continued FRG flow equations

    Christopher Jung🇩🇪 · Lorenz von Smekal🇩🇪

    In this work we study contributions due to vector and axial-vector meson fluctuations to their in-medium spectral functions in an effective low-energy theory inspired by the gauged linear sigma model. In particular, we show how to describe these fluctuations in the effective theory by massive (axial-)vector fields in agreement with the known structure of analogous single-particle or resonance contributions to the corresponding conserved currents. The vector and axial-vector meson spectral functions are then computed by numerically solving the analytically continued functional renormalization group (aFRG) flow equations for their retarded two-point functions at finite temperature and density in the effective theory. We identify the new contributions that arise due to the (axial-)vector meson fluctuations, and assess their influence on possible signatures of a QCD critical endpoint and the restoration of chiral symmetry in thermal dilepton spectra.

    hep-phPRD(2019)·28 citations
22. 22*

    Searching for Lorentz violation in high-energy colliders

    Zonghao Li🇺🇸

    Lorentz violation has been a popular field in recent years in the search for new physics beyond the Standard Model. We present a general method to build all Lorentz-violating terms in gauge field theories, including ones involving operators of arbitrary mass dimension. Applying these results to two types of experiments in high-energy colliders, light-by-light scattering and deep-inelastic scattering, we extract first bounds on certain coefficients for Lorentz violation.

    hep-ph0 citations
23. 23*

    Transition form factors and helicity amplitudes for electroexcitation of negative- and positive parity nucleon resonances in a light-front quark model

    Igor T. Obukhovsky🇷🇺 · Amand Faessler🇩🇪 · Dimitry K. Fedorov🇷🇺 · Thomas Gutsche🇩🇪 · Valery E. Lyubovitskij🇩🇪

    A workable basis of quark configurations $s^3$, $s^{2}p$ and $s{p}^2$ at light front has been constructed to describe the high-$Q^2$ behavior of transition form factors and helicity amplitudes in the electroproduction of the lightest nucleon resonances, $N_{1/2^{-}}(1535)$ and $N_{1/2^{+}}(1440)$. High-quality data of the CLAS Collaboration are described in the framework of a model which takes into account mixing of the quark configurations and the hadron-molecular states. The model allows for a rough estimate of the quark core weight in the wave function of the resonance in a comparison with high momentum transfer data on resonance electroproduction.

    hep-phPRD(2019)·22 citations
24. 24*

    Increasing the precision for $Z$ production at colliders: mixed QCD-QED effects

    German F. R. Sborlini🇪🇸

    In this talk, we describe the recent progress on the inclusion of mixed QCD-QED corrections for collider observables. In particular, we developed a formalism to extend $q_T$-resummation to deal with simultaneous emission of gluons and photons. We applied it to $Z$ production at colliders, and briefly discuss extensions to more complicated final states.

    hep-phhep-exPoS(2020)·0 citations
25. 25*

    Holographic Abelian Higgs model and the Linear confinement

    Eunseok Oh🇰🇷 · Sang-Jin Sin🇰🇷

    We consider the holographic abelian Higgs model and show that, in the absence of the scale symmetry breaking effect, chiral symmetry breaking gives linear confinement where the slope is given by the value of the chiral condensation. The model can be considered either as the theory of superconductivity or as the axial sector of QCD depending on the interpretation of the charge. We also provided a few models with linear confinement.

    hep-phhep-thPRD(2020)·5 citations
26. 26*

    Process-independent effective coupling and the pion structure function

    José Rodríguez-Quintero🇪🇸 · Lei Chang🇨🇳 · Khépani Raya🇨🇳 · Craig D. Roberts🇨🇳

    We sketch the calculation of the pion structure functions within the DSE framework, following two alternative albeit consistent approaches, and discuss then their QCD evolution, the running driven by an effective charge, from a hadronic scale up to any larger one accessible to experiment.

    hep-phnucl-exnucl-thJ.Phys.Conf.Ser.(2020)·9 citations
27. 27*

    Hide and Seek with Massive Fields in Modulus Mediation

    Ken-ichi Okumura🇯🇵

    We study the modulus mediation of supersymmetry breaking motivated by superstring theory. We show that the renormalization group running of the soft supersymmetry breaking parameters due to the interactions of massive fields is canceled by the threshold corrections at one-loop order, if their mass is given by nonperturbative dynamics controlled by the same modulus that mediates supersymmetry breaking and a sum rule of the modular weights holds for the Yukawa couplings. As an example, we discuss order reduction of lepton flavor violation in the supersymmetric seesaw mechanism, which revives the parameter space already excluded.

    hep-phhep-thPRL(2019)·1 citation
28. 28*

    Unified Description of Polarized and Unpolarized Quark Distributions in the Proton

    Tianbo Liu🇺🇸 · Raza Sabbir Sufian🇺🇸 · Guy F. de Téramond🇨🇷 · Hans Günter Dosch🇩🇪 · Stanley J. Brodsky🇺🇸 · Alexandre Deur🇺🇸

    We propose a unified new approach to describe polarized and unpolarized quark distributions in the proton based on the gauge-gravity correspondence, light-front holography, and the generalized Veneziano model. We find that the spin-dependent quark distributions are uniquely determined in terms of the unpolarized distributions by chirality separation without the introduction of additional free parameters. The predictions are consistent with existing experimental data and agree with perturbative QCD constraints at large longitudinal momentum $x$. In particular, we predict the sign reversal of the polarized down-quark distribution in the proton at $x=0.8\pm 0.03$, a key property of nucleon substructure which will be tested very soon in upcoming experiments.

    hep-phhep-exnucl-exnucl-thPRL(2020)·43 citations
29. 29*

    Transverse Parton Distribution and Fragmentation Functions at NNLO: the Gluon Case

    Ming-Xing Luo🇨🇳 · Tong-Zhi Yang🇨🇳 · Hua Xing Zhu🇨🇳 · Yu Jiao Zhu🇨🇳

    We calculate in this paper the perturbative gluon transverse momentum dependent parton distribution functions (TMDPDFs) and fragmentation functions (TMDFFs) using the exponential regulator for rapidity divergences. We obtain results for both unpolarized and linearly polarized distributions through next-to-next-to leading order in strong coupling constant, and through $\mathcal{O}({ϵ}^2)$ in dimensional regulator (finding discrepancy for the linearly polarized gluon TMDPDFs with a previous result in the literature). We find a nontrivial momentum conservation sum rule for the linearly polarized component for both TMDPDFs and TMDFFs in the $\mathcal{N}=1$ super-Yang-Mills theory. The TMDFFs are used to calculate the two-loop gluon jet function for the energy-energy correlator in Higgs gluonic decay in the back-to-back limit.

    hep-phJHEP(2020)·80 citations
30. 30*

    Quark model calculations of transition form factors at high photon virtualities

    G. Ramalho🇧🇷

    We present calculations of ${\gamma }^{\ast }N\to N^{\ast }$ transition form factors, where $N$ is the nucleon and $N^{\ast }$ is a nucleon resonance, based on a covariant quark model. Our main focus is at high photon virtualities (large $Q^2$) where the valence quark degrees of freedom dominate the contributions to the transition form factors and helicity amplitudes. In that regime, the quark model estimates can be compared with the available data, particularly with the Jefferson Lab data at intermediate and large momentum transfer ($Q^2>2$ GeV${}^2$). The main focus is on the $\Delta (1232)3/2^{+}$, $N(1440)1/2^{+}$, $N(1535)1/2^{-}$ and $N(1520)3/2^{-}$ resonances, but estimates for other higher mass resonances are also discussed.

    hep-phhep-exhep-latnucl-thEPJ Web Conf.(2020)·1 citation
31. 31*

    $k_t$-factorization vs collinear factorization in $W^{+}{W}^{-}$ pair production at the LHC

    N. Darvishi🇬🇧 · M.R. Masouminia🇬🇧 · K. Ostrolenk🇬🇧

    In this paper, we calculate the inclusive rate of $W^{+}{W}^{-}$ pair production through leptonic decay channels $W^{+}{W}^{-}\to l^{+}{\nu }_l+l^{\prime -}{\nu }_{l^{\prime }}$ in the $k_t$-factorization framework. We also consider the exclusive $W^{+}{W}^{-}$ pair production through the one-loop induced $gg\to H\to W^{+}{W}^{-}$ channel that is important for the study of new physics beyond the Standard Model. The results are compared with predictions from the Herwig 7 event generator in the collinear factorization framework and with the experimental data from the ATLAS and the CMS collaborations. It will be shown that our predictions for the $W^{+}{W}^{-}$ boson pair production signals are in agreement with the experimental data as well as the collinear results.

    hep-phPRD(2020)·7 citations
32. 32*

    Higgs boson potential at colliders: status and perspectives

    B. Di Micco🇮🇹 · M. Gouzevitch🇫🇷 · J. Mazzitelli🇨🇭 · C. Vernieri (editors)🇺🇸 · J. Alison🇺🇸 · K. Androsov🇮🇹 · J. Baglio🇩🇪 · E. Bagnaschi🇨🇭 · S. Banerjee🇬🇧 · P. Basler🇩🇪 · A. Bethani🇬🇧 · A. Betti🇺🇸 and 95 other authors

    This document summarises the current theoretical and experimental status of the di-Higgs boson production searches, and of the direct and indirect constraints on the Higgs boson self-coupling, with the wish to serve as a useful guide for the next years. The document discusses the theoretical status, including state-of-the-art predictions for di-Higgs cross sections, developments on the effective field theory approach, and studies on specific new physics scenarios that can show up in the di-Higgs final state. The status of di-Higgs searches and the direct and indirect constraints on the Higgs self-coupling at the LHC are presented, with an overview of the relevant experimental techniques, and covering all the variety of relevant signatures. Finally, the capabilities of future colliders in determining the Higgs self-coupling are addressed, comparing the projected precision that can be obtained in such facilities. The work has started as the proceedings of the Di-Higgs workshop at Colliders, held at Fermilab from the 4th to the 9th of September 2018, but it went beyond the topics discussed at that workshop and included further developments.

    hep-phhep-exRev.Phys.(2020)·295 citations
33. 33*

    $Z^{\prime }$ models with less-minimal flavour violation

    Lorenzo Calibbi🇨🇳 · Andreas Crivellin🇨🇭 · Fiona Kirk🇨🇭 · Claudio Andrea Manzari🇨🇭 · Leonardo Vernazza🇳🇱

    We study the phenomenology of simplified $Z^{\prime }$ models with a global $U(2{)}^3$ flavour symmetry in the quark sector, broken solely by the Standard Model Yukawa couplings. This flavour symmetry, known as less-minimal flavour violation, protects $\Delta F=2$ processes from dangerously large new physics (NP) effects, and at the same time provides a free complex phase in $b\to s$ transitions, allowing for an explanation of the hints for additional direct CP violation in kaon decays (${ϵ}^{\prime }/ϵ$) and in hadronic $B$-decays ($B\to K\pi$ puzzle). Furthermore, once the couplings of the $Z^{\prime }$ boson to the leptons are included, it is possible to address the intriguing hints for NP (above the 5$\sigma$ level) in $b\to s{\ell }^{+}{\ell }^{-}$ transitions. Taking into account all flavour observables in a global fit, we find that ${ϵ}^{\prime }/ϵ$, the $B\to K\pi$ puzzle and $b\to s{\ell }^{+}{\ell }^{-}$ data can be explained simultaneously. Sizeable CP violation in $b\to s{\ell }^{+}{\ell }^{-}$ observables, in particular $A_8$, is predicted, which can be tested in the near future, and an explanation of the $B\to K\pi$ and ${ϵ}^{\prime }/ϵ$ puzzles leads to effects in di-jet tails at the LHC, that are not far below the current limits. Once $b\to s{\ell }^{+}{\ell }^{-}$ is included, cancellations in di-muon tails, possibly by a second $Z^{\prime }$, are required by LHC data.

    hep-phhep-exhep-latPRD(2020)·60 citations
34. 34*

    Model-independent test of the parity symmetry of gravity with gravitational waves

    Wen Zhao🇨🇳 · Tan Liu🇨🇳 · Linqing Wen🇦🇺 · Tao Zhu🇨🇳 · Anzhong Wang🇺🇸 · Qian Hu🇨🇳 · Cong Zhou🇨🇳

    Gravitational wave (GW) data can be used to test the parity symmetry of gravity by investigating the difference between left-hand and right-hand circular polarization modes. In this article, we develop a method to decompose the circular polarizations of GWs produced during the inspiralling stage of compact binaries, with the help of stationary phase approximation. The foremost advantage is that this method is simple, clean, independent of GW waveform, and is applicable to the existing detector network. Applying it to the mock data, we test the parity symmetry of gravity by constraining the velocity birefringence of GWs. If a nearly edge-on binary neutron-stars with observed electromagnetic counterparts at 40 Mpc is detected by the second-generation detector network, one could derive the model-independent test on the parity symmetry in gravity: the lower limit of the energy scale of parity violation can be constrained within $\mathcal{O}(10^4\mathrm{eV})$.

    ↳ gr-qcastro-ph.COhep-phhep-thEPJC(2020)·43 citations
35. 35*

    Meson-Nucleon Scattering Amplitudes from Lattice QCD

    John Bulava🇩🇰

    Lattice QCD calculations of resonant meson-meson scattering amplitudes have improved significantly due to algorithmic and computational advances. However, progress in meson-nucleon scattering has been slower due to difficulties in computing the necessary correlation functions, the exponential signal-to-noise problem, and the finite-volume treatment of scattering with fermions. Nonetheless, first benchmark calculations have now been performed. The status of lattice QCD calculations of meson-nucleon scattering amplitudes is reviewed together with comments on future prospects.

    ↳ hep-lathep-phAIP Conf.Proc.(2020)·9 citations
36. 36*

    Effective $J$-factors for Milky Way dwarf spheroidal galaxies with velocity-dependent annihilation

    Kimberly K. Boddy🇺🇸 · Jason Kumar🇺🇸 · Andrew B. Pace🇺🇸 · Jack Runburg🇺🇸 · Louis E. Strigari🇺🇸

    We calculate the effective $J$-factors, which determine the strength of indirect detection signals from dark matter annihilation, for 25 dwarf spheroidal galaxies (dSphs). We consider several well-motivated assumptions for the relative velocity dependence of the dark matter annihilation cross section: ${\sigma }_{A}v$: $s$-wave (velocity independent), $p$-wave (${\sigma }_{A}v\propto v^2$), $d$-wave (${\sigma }_{A}v\propto v^4$), and Sommerfeld-enhancement in the Coulomb limit (${\sigma }_{A}v\propto 1/v$). As a result we provide the largest and most updated sample of J-factors for velocity-dependent annihilation models. For each scenario, we use Fermi-LAT gamma-ray data to constrain the annihilation cross section. Due to the assumptions made in our gamma-ray data analysis, our bounds are comparable to previous bounds on both the $p$-wave and Sommerfeld-enhanced cross sections using dSphs. Our bounds on the $d$-wave cross section are the first such bounds using indirect detection data.

    ↳ astro-ph.COastro-ph.GAhep-phPRD(2020)·56 citations
37. 37*

    Stationary scalar hairy configurations supported by Neumann compact stars

    Yan Peng🇨🇳

    We study stationary scalar field hairy configurations supported by asymptotically flat horizonless compact stars. At the star surface, we impose Neumann boundary conditions for the scalar field. With analytical methods, we obtain bounds on the frequency of scalar fields. For certain discrete frequency satisfying the bounds, we numerically get solutions of scalar hairy stars. We also disclose effects of model parameters on the discrete frequency of scalar fields.

    ↳ gr-qchep-phhep-thNPB(2020)·5 citations
38. 38*

    Long-distance Contributions to Neutrinoless Double Beta Decay ${\pi }^{-}\to {\pi }^{+}ee$

    Xin-Yu Tuo🇨🇳 · Xu Feng🇨🇳 · Lu-Chang Jin🇺🇸

    Neutrinoless double beta decay, if detected, would prove that neutrinos are Majorana fermions and provide the direct evidence for lepton number violation. If such decay would exist in nature, then ${\pi }^{-}{\pi }^{-}\to ee$ and ${\pi }^{-}\to {\pi }^{+}ee$ (or equivalently ${\pi }^{-}{e}^{+}\to {\pi }^{+}{e}^{-}$) are the two simplest processes accessible via first-principle lattice QCD calculations. In this work, we calculate the long-distance contributions to the ${\pi }^{-}\to {\pi }^{+}ee$ transition amplitude using four ensembles at the physical pion mass with various volumes and lattice spacings. We adopt the infinite-volume reconstruction method to control the finite-volume effects arising from the (almost) massless neutrino. Providing the lattice QCD inputs for chiral perturbation theory, we obtain the low energy constant $g_{\nu }^{\pi \pi }(m_{\rho })=-10.89(28{)}_{\text{stat}}(74{)}_{\text{sys}}$, which is close to $g_{\nu }^{\pi \pi }(m_{\rho })=-11.96(31{)}_{\text{stat}}$ determined from the crossed-channel ${\pi }^{-}{\pi }^{-}\to ee$ decay.

    ↳ hep-lathep-phnucl-exnucl-thPRD(2019)·56 citations
39. 39*

    Spin Orbit Correlations and the Structure of the Nucleon

    Harut Avakian🇺🇸 · Bakur Parsamyan🇨🇭 · Alexey Prokudin🇺🇸

    Extensive experimental measurements of spin and azimuthal asymmetries in various processes have stimulated theoretical interest and progress in studies of the nucleon structure. Interpretation of experimental data in terms of parton distribution functions, generalized to describe transverse momentum and spatial parton distributions, is one of the main remaining challenges of modern nuclear physics. These new parton distribution and fragmentation functions encode the motion and the position of partons and are often referred to as three-dimensional distributions describing the three-dimensional (3D) structure of the nucleon. Understanding of the production mechanism and performing phenomenological studies compatible with factorization theorems using minimal model assumptions are goals of analysis of the experimental data. HERMES and COMPASS Collaborations and experiments at Jefferson Lab have collected a wealth of polarized and unpolarized Semi-Inclusive Deep Inelastic Scattering (SIDIS) data. These data play a crucial role in current understanding of nucleon spin-phenomena as they cover a broad kinematical range. The Jefferson Lab 12 GeV upgrade data on polarized and unpolarized SIDIS will have remarkably higher precision at large parton fractional momentum $x$ compared to the existing data. We argue that both experimental and phenomenological communities will benefit from development of a comprehensive extraction framework that will facilitate extraction of 3D nucleon structure, help understand various assumptions in extraction and data analysis, help to insure the model independence of the experimental data and validate the extracted functions. In this review we present the latest developments in the field of the spin asymmetries and discuss different components involved in precision extraction of 3D partonic distribution and fragmentation functions.

    ↳ hep-exhep-phRiv.Nuovo Cim.(2019)·27 citations
40. 40*

    Long-range azimuthal correlations for partially coherent pion emission in proton-proton collisions

    Peng Ru🇨🇳 · Wei-Ning Zhang🇨🇳

    In this paper, we investigate the influence of coherent pion emission on long-range azimuthal correlations in relativistic proton-proton collisions. We study the pion momentum distribution for a coherent source with both transverse and Bjorken longitudinal expansions, and calculate the two-particle correlation function $C(\Delta \eta ,\Delta \varphi )$. A "ridge" structure is observed in the correlation function $C(\Delta \eta ,\Delta \varphi )$ of the coherent pion emission, whether the coherent source is expanding or static. The onset of this long-range azimuthal correlation can be traced back to the asymmetric initial transverse profile of the coherent source, owing to the interference in coherent emission. We further construct a partially coherent pion-emitting source by incorporating a chaotic emission component. From the experimental data of the two-pion Hanbury-Brown-Twiss correlations in pp collisions at $\sqrt{s}=7$TeV, we extract a coherent fraction of pion emission, which increases with increasing charged-particle multiplicity, as an input of the partially coherent source model. The ridge structure is observed in the correlation function $C(\Delta \eta ,\Delta \varphi )$ for the partially coherent source. The correlation becomes stronger at higher multiplicities because of the larger degrees of coherence. The results in this work are meaningful for fully understanding the collectivity in the small system of pp collisions.

    ↳ nucl-thhep-phPLB(2020)·1 citation
41. 41*

    Form factors for the Nucleon-to-Roper electromagnetic transition at large-$Q^2$

    José Rodríguez-Quintero🇪🇸 · Daniele Binosi🇮🇹 · Chen Chen🇩🇪 · Ya Lu🇨🇳 · Craig D. Roberts🇨🇳 · Jorge Segovia🇪🇸

    We report on a recent calculation of all Roper-related electromagnetic transtions form factors, covering the range of energies that next-to-come planned experiments are expected to map. Direct reliable calculations were performed, within a Poincaré covariant approach of the three-body bound-state problem, up to $Q^2/m_N^2$=6; approximated then by applying the Schlessinger point method and the results eventually extended up to $Q^2/m_N^2\simeq$12 via analytic continuation.

    ↳ nucl-thhep-phnucl-exEPJ Web Conf.(2020)·8 citations
42. 42*

    Thermodynamics of AdS${}_5$ black holes: holographic QCD and Stückelberg model

    Eugenio Megias🇪🇸

    We explore the thermodynamics of AdS${}_5$ black holes in two models: i) an improved holographic QCD model with a simple dilaton potential, and ii) the Stückelberg model in 5D. In the former case, by applying techniques of singular perturbation theory, we obtain a resummation of the naive expansion at high temperatures, providing a good fit to the lattice data for the trace anomaly. In the latter, we find a solution of the equations of motion by considering an expansion in the conformal dimension of the current associated to the gauge field.

    ↳ hep-thgr-qchep-phJ.Phys.Conf.Ser.(2019)·3 citations
43. 43*

    Direct Detection of Dark Matter Substructure in Strong Lens Images with Convolutional Neural Networks

    Ana Diaz Rivero🇺🇸 · Cora Dvorkin🇺🇸

    Strong gravitational lensing is a promising way of uncovering the nature of dark matter, by finding perturbations to images that cannot be well accounted for by modeling the lens galaxy without additional structure, be it subhalos (smaller halos within the smooth lens) or line-of-sight (LOS) halos. We present results attempting to infer the presence of substructure from images without requiring an intermediate step in which a smooth model has to be subtracted, using a simple convolutional neural network (CNN). We find that the network is only able to infer the presence of subhalos with $>75\%$ accuracy when they have masses of $\ge 5\times 10^9$M${}_{\odot }$ if they lie within the main lens galaxy. Since less massive foreground LOS halos can have the same effect as higher mass subhalos, the CNN can probe lower masses in the halo mass function. The accuracy does not improve significantly if we add a population of less massive subhalos. With the expectation of experiments such as HST and Euclid yielding thousands of high-quality strong lensing images in the next years, having a way of analyzing images quickly to identify candidates that merit further analysis to determine individual subhalo properties while preventing extensive resources being used for images that would yield null detections could be very useful. By understanding the sensitivity as a function of substructure mass, non-detections could be combined with the information from images with substructure to constrain the cold dark matter scenario, in particular if the sensitivity can be pushed to lower masses.

    ↳ astro-ph.COastro-ph.HEastro-ph.IMhep-ph+1PRD(2020)·47 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.