Mon·May 25, 2020Monday·May 25, 2020

1. 01*

   Heavy Hybrid Decays in a Constituent Gluon Model

   Christian Farina🇺🇸 · Hugo Garcia Tecocoatzi🇮🇹 · Alessandro Giachino🇮🇹 · Elena Santopinto🇮🇹 · Eric S. Swanson🇺🇸

   A constituent gluon model that is informed by recent lattice field theory is developed. The model is then used to compute hybrid strong decay widths, that can be useful for the GlueX collaboration at Jefferson Lab and the PANDA collaboration at FAIR. Commensurately, forthcoming data from GlueX and PANDA will test the model. Widths tend to be large except for those of the lightest hybrid $S$-wave multiplet. Selection rules, extensions, limitations, and applications are discussed.

   hep-phPRD(2020)·28 citations
2. 02*

   One-loop matching for the twist-3 parton distribution $g_T(x)$

   Shohini Bhattacharya🇺🇸 · Krzysztof Cichy🇵🇱 · Martha Constantinou🇺🇸 · Andreas Metz🇺🇸 · Aurora Scapellato🇵🇱 · Fernanda Steffens🇩🇪

   Perturbative matching relates the parton quasi-distributions, defined by Euclidean correlators at finite hadron momenta, to the light-cone distributions which are accessible in experiments. Previous matching calculations have exclusively focused on twist-2 distributions. In this work, we address, for the first time, the one-loop matching for the twist-3 parton distribution function $g_T(x)$. The results have been obtained using three different infrared regulators, while dimensional regularization has been adopted to deal with the ultraviolet divergences. We present the renormalized expressions of the matching coefficient for $g_T(x)$ in the $\overline{\mathrm{MS}}$ and modified $\overline{\mathrm{MS}}$ schemes. We also discuss the role played by a zero-mode contribution. Our results have already been used for the extraction of $g_T(x)$ from lattice QCD calculations.

   hep-phhep-latPRD(2020)·55 citations
3. 03*

   QCD Corrections to $e^{+}{e}^{-}\to H^{\pm }{W}^{\mp }$ in Type-I THDM at Electron Positron Colliders

   Qiang Yang🇨🇳 · Ren-You Zhang🇨🇳 · Ming-Ming Long🇨🇳 · Shao-Ming Wang🇨🇳 · Wen-Gan Ma🇨🇳 · Jian-Wen Zhu🇨🇳 · Yi Jiang🇨🇳

   We investigate in detail the charged Higgs production associated with a $W$ boson at electron-positron colliders within the framework of the Type-I two-Higgs-doublet model (THDM). We calculate the integrated cross section at the LO and analyze the dependence of the cross section on the THDM parameters and the colliding energy in a benchmark scenario of the input parameters of Higgs sector. The numerical results show that the integrated cross section is sensitive to the charged Higgs mass, especially in the vicinity of $m_{H^{\pm }}\simeq 184\mathrm{GeV}$ at a $500\mathrm{GeV}$ $e^{+}{e}^{-}$ collider, and decreases consistently as the increment of $\tan \beta$ in the low $\tan \beta$ region. The peak in the colliding energy distribution of the cross section arises from the resonance of loop integrals and its position moves towards low colliding energy as the increment of $m_{H^{\pm }}$. We also study the two-loop NLO QCD corrections to both the integrated cross section and the angular distribution of the charged Higgs boson, and find that the QCD relative correction is also sensitive to the charged Higgs mass and strongly depends on the final-state phase space. For $\tan \beta =2$, the QCD relative correction at a $500\mathrm{GeV}$ $e^{+}{e}^{-}$ collider varies in the range of $[-10\%,11\%]$ as $m_{H^{\pm }}$ increases from $150$ to $400\mathrm{GeV}$.

   hep-phCPC(2020)·7 citations
4. 04*

   Gauge invariance and amplitudes of two-photon processes

   P.A. Krachkov🇷🇺 · A.I. Milstein🇷🇺 · A.G. Shamov🇷🇺

   A method to derive the convenient representations for many two-photon amplitudes is suggested. It is based on the use of the gauge in which the photon propagator has only space components. The amplitudes obtained have no any strong numerical cancellations and, therefore, are very convenient for numerical evaluations. Our approach is illustrated by the consideration of the processes $e^{+}{e}^{-}\to e^{+}{e}^{-}{e}^{+}{e}^{-}$, $e^{+}{e}^{-}\to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$, and $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}{\pi }^{+}{\pi }^{-}$. The method is extended on the case of polarized particles. The amplitudes obtained in this approach have been employed for extension of the event generator developed by F.A. Berends, P.H. Daverveldt, and R. Kleiss.

   hep-phComput.Phys.Commun.(2020)·0 citations
5. 05*

   Evolution of pomeron and odderon at all angular momemnta

   M.A.Braun🇷🇺

   In the QCD the small~$x$ evolution of the interacting pomerons and odderons is studied with all angular momenta $l$ taken into account. The resulting system of coupled nonlinear evolution equations is formulated in the momentum space and solved numerically. Excellent convergence in $l$ is observed. Also it is found that states with $l>1$ play an important role and substantially reduce the basic pomeron state at large rapidities

   hep-phPLB(2020)·4 citations
6. 06*

   Probing triple Higgs coupling with machine learning at the LHC

   Murat Abdughani🇨🇳 · Daohan Wang🇨🇳 · Lei Wu🇨🇳 · Jin Min Yang🇨🇳 · Jun Zhao🇨🇳

   Measuring the triple Higgs coupling is a crucial task in the LHC and future collider experiments. We apply the Message Passing Neural Network (MPNN) to the study of the non-resonant Higgs pair production process $pp\to hh$ in the final state with $2b+2\ell +E_{\mathrm{T}}^{\mathrm{miss}}$ at the LHC. Although the MPNN can improve the signal significance, it is still challenging to observe such a process at the LHC. We find that a $2\sigma$ upper bound (including a 10\% systematic uncertainty) on the production cross section of the Higgs pair is 3.7 times the predicted SM cross section at the LHC with the luminosity of 3000 fb${}^{-1}$, which will limit the triple Higgs coupling to the range of $[-3,11.5]$.

   hep-phhep-exPRD(2021)·40 citations
7. 07*

   The $\rho$ parameter and $H^0\to {\ell }_i{\ell }_j$ in models with TeV sterile neutrinos

   G. Hernández-Tomé🇪🇸 · J. I. Illana🇪🇸 · M. Masip🇪🇸

   The presence of massive sterile neutrinos $N$ mixed with the active ones induces flavor violating processes in the charged lepton sector at the loop level. In particular, the amplitude of $H^0\to {\bar{\ell }}_i{\ell }_j$ is expected to be proportional to the product of heavy-light Yukawa couplings $y_i{y}_j=2s_{{\nu }_i}{s}_{{\nu }_j}{m}_N^2/v^2$, where $s_{{\nu }_{i,j}}$ express the heavy-light neutrino mixings. Here we revisit these Higgs decays in the most generic extension of the neutrino sector, focusing on large values of $y_i$. We show that decoupling effects and a cancellation between the two dominant contributions to these processes makes the amplitude about one hundred times smaller than anticipated. We find that perturbative values of $y_i$ giving an acceptable contribution to the $\rho$ parameter imply $\mathcal{B}(H^0\to {\bar{\ell }}_i{\ell }_j)<10^{-8}$ for any lepton flavors, a rate that is not accessible at current colliders.

   hep-phPRD(2020)·22 citations
8. 08*

   Amplitudes separation and strong-electromagnetic relative phase in the $\psi (2S)$ decays into baryons

   Rinaldo Baldini Ferroli🇮🇹 · Alessio Mangoni🇮🇹 · Simone Pacetti🇮🇹 · Kai Zhu🇨🇳

   The strong, electromagnetic and mixed strong-electromagnetic amplitudes of the $\psi (2S)$ decays into baryon-anti-baryon pairs have been obtained by exploiting all available data sets in the framework of an effective Lagrangian model. We observed that at the $\psi (2S)$ mass the QCD regime is not completely perturbative, as can be inferred by the relative strength of the strong and the mixed strong-electromagnetic amplitudes. Recently a similar conclusion has been reached also for the $J/\psi$ decays. The relative phase between the strong and the electromagnetic amplitudes is $\phi =(58\pm 8{)}^{\circ }$, to be compared with $\phi =(73\pm 8{)}^{\circ }$ obtained for the $J/\psi$. On the other hand, in the case of the $\psi (2S)$ meson, different values of the ratio between strong and mixed strong-electromagnetic amplitudes are phenomenologically required, while for the $J/\psi$ meson only one ratio was enough to describe the data. Finally, we also observed a peculiar behavior of the mixed strong-electromagnetic amplitudes of the decays $\psi (2S)\to {\Sigma }^{+}\overline{\Sigma }{}^{-}$ and $\psi (2S)\to {\Sigma }^{-}\overline{\Sigma }{}^{+}$.

   hep-phPRD(2021)·11 citations
9. 09*

   Model comparison for initial density fluctuations in high energy heavy ion collisions

   Stefan Floerchinger🇩🇪 · Eduardo Grossi🇺🇸 · Kianusch Vahid Yousefnia🇩🇪

   Four models for the initial conditions of a fluid dynamic description of high energy heavy ion collisions are analysed and compared. We study expectation values and event-by-event fluctuations in the initial transverse energy density profiles from Pb-Pb collisions. Specifically, introducing a Fourier-Bessel mode expansion for fluctuations, we determine expectation values and two-mode correlation functions of the expansion coefficients. The analytically solveable independent point-sources model is compared to an initial state model based on Glauber theory and two models based on the Color Glass Condensate framework. We find that the large wavelength modes of all investigated models show universal properties for central collisions and also discuss to which extent general properties of initial conditions can be understood analytically.

   hep-phnucl-thPRC(2020)·7 citations
10. 10*

    On the connection between quark propagation and hadronization

    Alberto Accardi🇺🇸 · Andrea Signori🇺🇸

    We investigate the properties and structure of the recently discussed "fully inclusive jet correlator", namely, the gauge-invariant field correlator characterizing the final state hadrons produced by a free quark as this propagates in the vacuum. Working at the operator level, we connect this object to the single-hadron fragmentation correlator of a quark, and exploit a novel gauge invariant spectral decomposition technique to derive a complete set of momentum sum rules for quark fragmentation functions up to twist-3 level; known results are recovered, and new sum rules proposed. We then show how one can explicitly connect quark hadronization and dynamical quark mass generation by studying the inclusive jet's gauge-invariant mass term. This mass is, on the one hand, theoretically related to the integrated chiral-odd spectral function of the quark, and, on the other hand, is experimentally accessible through the $E$ and $\tilde{E}$ twist-3 fragmentation function sum rules. Thus, measurements of these fragmentation functions in deep inelastic processes provide one with an experimental gateway into the dynamical generation of mass in Quantum Chromodynamics.

    hep-phhep-exnucl-thEPJC(2020)·23 citations
11. 11*

    Decay of the pseudoscalar glueball into vector, axial-vector, scalar and pseudoscalar mesons

    Walaa I. Eshraim🇦🇪

    We resume the investigation of the ground-state pseudoscalar glueball, $J^{PC}=0^{-+}$, by computing its two- and three-body decays into vector and axial-vector quark-antiquark meson fields additional to scalar and pseudoscalar mesons through the construction of an interaction chiral Lagrangian that produces these decays. We evaluate the branching ratio, via a parameter-free calculation, by setting the mass of the pseudoscalar glueball to $2.6$ GeV as predicted by lattice QCD simulations. We duplicate the computation for the branching ratios for a pseudoscalar glueball mass $2.37$ GeV which matches to the measured mass of the resonance $X(2370)$ in the BESIII experiment. The present channels and states are potentially reached and are interesting for the running BESIII and Belle-II experiments and the planned PANDA experiment at FAIR/GSI which will be able to detect the pseudoscalar glueball within the accessible energy range.

    hep-phnucl-thEPJC(2023)·10 citations
12. 12*

    Phenomenology of NNLO jet production at the LHC and its impact on parton distributions

    Rabah Abdul Khalek🇳🇱 · Stefano Forte🇮🇹 · Thomas Gehrmann🇨🇭 · Aude Gehrmann-De Ridder🇨🇭 · Tommaso Giani🇬🇧 · Nigel Glover🇬🇧 · Alexander Huss🇨🇭 · Emanuele R. Nocera🇳🇱 · Joao Pires🇵🇹 · Juan Rojo🇳🇱 · Giovanni Stagnitto🇫🇷

    We present a systematic investigation of jet production at hadron colliders from a phenomenological point of view, with the dual aim of providing a validation of theoretical calculations and guidance to future determinations of parton distributions (PDFs). We account for all available inclusive jet and dijet production measurements from ATLAS and CMS at 7 and 8 TeV by including them in a global PDF determination, and comparing to theoretical predictions at NNLO QCD supplemented by electroweak (EW) corrections. We assess the compatibility of the PDFs, specifically the gluon, obtained before and after inclusion of the jet data. We compare the single-inclusive jet and dijet observables in terms of perturbative behaviour upon inclusion of QCD and EW corrections, impact on the PDFs, and global fit quality. In the single-inclusive case, we also investigate the role played by different scale choices and the stability of the results upon changes in modelling of the correlated experimental systematics.

    hep-phhep-exEPJC(2020)·65 citations
13. 13*

    Cosmic Inflation in Minimal $U(1{)}_{B-L}$ Model: Implications for (Non) Thermal Dark Matter and Leptogenesis

    Debasish Borah🇮🇳 · Suruj Jyoti Das🇮🇳 · Abhijit Kumar Saha🇮🇳

    We study the possibility of realising cosmic inflation, dark matter (DM), baryon asymmetry of the universe (BAU) and light neutrino masses in non-supersymmetric minimal gauged $B-L$ extension of the standard model with three right handed neutrinos. The singlet scalar field responsible for spontaneous breaking of $B-L$ gauge symmetry also plays the role of inflaton by virtue of its non-minimal coupling to gravity. While the lightest right handed neutrino is the DM candidate, being stabilised by an additional $Z_2$ symmetry, we show by performing a detailed renormalisation group evolution (RGE) improved study of inflationary dynamics that thermal DM is generally overproduced due to insufficient annihilations through gauge and scalar portals. This happens due to strict upper limits obtained on gauge and other dimensionless couplings responsible for DM annihilation while assuming the non-minimal coupling to gravity to be at most of order unity. The non-thermal DM scenario is viable, with or without $Z_2$ symmetry, although in such a case the $B-L$ gauge sector remains decoupled from the inflationary dynamics due to tiny couplings. We also show that the reheat temperature predicted by the model prefers non-thermal leptogenesis with hierarchical right handed neutrinos while being consistent with other requirements.

    hep-phastro-ph.COEPJC(2021)·26 citations
14. 14*

    Thermodynamics of a two-step electroweak phase transition

    Lauri Niemi🇫🇮 · Michael J. Ramsey-Musolf🇺🇸 · Tuomas V.I. Tenkanen🇨🇭 · David J. Weir🇫🇮

    New field content beyond that of the Standard Model of particle physics can alter the thermal history of electroweak symmetry breaking in the early universe. In particular, the symmetry breaking may have occurred through a sequence of successive phase transitions. We study the thermodynamics of such scenario in a real triplet extension of the Standard Model, using nonperturbative lattice simulations. Two-step electroweak phase transition is found to occur in a narrow region of allowed parameter space with the second transition always being first order. The first transition into the phase of non-vanishing triplet vacuum expectation value is first order in a non-negligible portion of the two-step parameter space. A comparison with 2-loop perturbative calculation is provided and significant discrepancies with the nonperturbative results are identified.

    hep-phhep-latPRL(2021)·114 citations
15. 15*

    On the impact of non-factorisable corrections in VBF single and double Higgs production

    Frédéric A. Dreyer🇬🇧 · Alexander Karlberg🇬🇧 · Lorenzo Tancredi🇬🇧

    We study the factorisable and non-factorisable QCD corrections to Vector-Boson Fusion single and double Higgs production and show the combined corrections for both processes at $\mathcal{O}({\alpha }_s^2)$. We investigate the validity of the eikonal approximation with and without selection cuts, and carry out an in-depth study of the relative size of the non-factorisable next-to-next-to-leading order corrections compared to the factorisable ones. In the case of single Higgs production, after selection cuts are applied, the non-factorisable corrections are found to be mostly contained within the factorisable scale uncertainty bands. When no cuts are applied, instead, the non-factorisable corrections are slightly outside the scale uncertainty band. Interestingly, for double Higgs production, we find that both before and after applying cuts, non-factorisable corrections are enhanced compared to the single Higgs case. We trace this enhancement to the existence of delicate cancellations between the various leading-order Feynman diagrams, which are partly spoiled by radiative corrections. All the studied contributions have been implemented in proVBFH v1.2.0 and proVBFHH v1.1.0.

    hep-phhep-exJHEP(2020)·39 citations
16. 16*

    Field-theoretic derivation of bubble-wall force

    Marc Barroso Mancha🇩🇪 · Tomislav Prokopec🇳🇱 · Bogumila Swiezewska🇳🇱

    We derive a general quantum field theoretic formula for the force acting on expanding bubbles of a first order phase transition in the early Universe setting. In the thermodynamic limit the force is proportional to the entropy increase across the bubble of active species that exert a force on the bubble interface. When local thermal equilibrium is attained, we find a strong friction force which grows as the Lorentz factor squared, such that the bubbles quickly reach stationary state and cannot run away. We also study an opposite case when scatterings are negligible across the wall (ballistic limit), finding that the force saturates for moderate Lorentz factors thus allowing for a runaway behavior. We apply our formalism to a massive real scalar field, the standard model and its simple portal extension. For completeness, we also present a derivation of the renormalized, one-loop, thermal energy-momentum tensor for the standard model and demonstrate its gauge independence.

    ↳ hep-thastro-ph.COhep-phJHEP(2021)·108 citations
17. 17*

    Reactor neutrino applications and coherent elastic neutrino nucleus scattering

    Maitland Bowen🇺🇸 · Patrick Huber🇺🇸

    Potential applications of neutrino detection to nuclear security have been discussed since the 1970s. Recent years have seen great progress in detector technologies based on inverse beta decay, with the demonstration of ton-scale surface-level detectors capable of high quality neutrino spectrum measurements. At the same time coherent elastic neutrino nucleus scattering has been experimentally confirmed in 2017 with neutrinos from stopped pion decay and there is a number of experiments aimed at seeing this reaction with reactor neutrinos. The large cross section and threshold-less nature of this reaction make it plausible to consider it for applications to nuclear security and here, we present a first direct comparison of the two reaction modes.

    ↳ physics.ins-dethep-exhep-phnucl-ex+1PRD(2020)·32 citations
18. 18*

    Cosmic Rays and Spectral Distortions from Collapsing Textures

    Robert Brandenberger🇨🇦 · Bryce Cyr🇨🇦 · Hao Jiao (McGill University and USTC)🇨🇳

    We compute the energy spectrum of photons and neutrinos produced by the unwinding of a scaling distribution of cosmic textures, and discuss the implications for the spectrum of high energy cosmic rays, and for CMB spectral distortions. Textures lead to a contribution to the photon flux which scales as $E^{3}F(E)\sim E^{3/2}$. Hence, the tightest constraints on the texture model come from the highest energies from which primordial photons can reach us without being scattered by the CMB and other foregrounds. Textures lead to both $\mu$ type and $y$ type distortions. While the constraints on the texture model coming from the current COBE bounds are weaker than the bounds from the angular power spectrum of the CMB, future surveys such as PIXIE can lead to stronger bounds. The high energy neutrino flux is constrained by data from the Pierre Auger experiment and yields a bound on the energy scale of textures which is competitive with CMB bounds.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2020)·2 citations
19. 19*

    A $b$-baryon sonata

    Yasmine Sara Amhis🇫🇷

    LHCb is one of the four experiments at the Large Hadron Collider (CERN), dedicated to the study of b-hadrons. Throughout my research, I studied in particular b-baryons which are abundantly produced at the LHCb. My habilitation summarises the studies of fundamental properties of these particles within the Standard Model. In particular, I discuss both lifetime and mass measurements. This work is followed by a search of New Physics using a Lepton universality test. Finally, I discuss my contribution to the upgrade detectors of the LHCb experiment in particular those related to the calorimeter and the scintillator fibre tracker.

    ↳ hep-exhep-ph0 citations
20. 20*

    Heavy flavor dynamics across system size at the LHC

    Roland Katz🇫🇷 · Caio A. G. Prado🇨🇳 · Jacquelyn Noronha-Hostler🇺🇸 · Alexandre A. P. Suaide🇧🇷

    One of the fundamental signatures of the Quark Gluon Plasma has been the suppression of heavy flavor (specifically D mesons), which has been measured via the nuclear modification factor, $R_{AA}$ and azimuthal anisotropies, $v_n$, in large systems. However, multiple competing models can reproduce the same data for $R_{AA}$ to $v_n$. In this talk we break down the competing effects that conspire together to successfully reproduce $R_{AA}$ and $v_n$ in experimental data using Trento+v-USPhydro+DAB-MOD. Then using our best fit model we make predictions for $R_{AA}$ and $v_n$ across system size for ${}^{208}PbPb$, ${}^{129}XeXe$, ${}^{40}ArAr$, and ${}^{16}OO$ collisions. We find that 0--10\% centrality has a non-trivial interplay between the system size and eccentricities such that system size effects are masked in $v_2$ whereas in 30--50\% centrality the eccentricities are approximately constant across system size and, therefore, is a better centrality class to study D meson dynamics across system size.

    ↳ nucl-thhep-phnucl-exJ.Phys.Conf.Ser.(2020)·0 citations
21. 21*

    Analytic SU(N) Skyrmions at finite Baryon density

    Pedro D. Alvarez🇨🇱 · Sergio L. Cacciatori🇮🇹 · Fabrizio Canfora🇨🇱 · Bianca L. Cerchiai🇮🇹

    We construct analytic (3+1)-dimensional Skyrmions living at finite Baryon density in the SU(N) Skyrme model that are not trivial embeddings of SU(2) into SU(N). We used Euler angles decomposition for arbitrary N and the generalized hedgehog Ansatz at finite Baryon density. The Skyrmions of high topological charge that we find represent smooth Baryonic layers whose properties can be computed explicitly. In particular, we determine the energy to Baryon charge ratio for any N showing the smoothness of the large N limit. The closeness to the BPS bound of these configurations can also be analyzed. The energy density profiles of these finite density Skyrmions have \textit{lasagna-like} shape in agreement with recent experimental findings. The shear modulus can be precisely estimated as well and our analytical result is close to recent numerical studies in the literature.

    ↳ hep-thhep-phnucl-thPRD(2020)·29 citations
22. 22*

    Thermalization of large energy release in the early Universe

    Jens Chluba🇬🇧 · Andrea Ravenni🇬🇧 · Sandeep Kumar Acharya🇬🇧

    Spectral distortions of the cosmic microwave background (CMB) provide a unique tool for learning about the early phases of cosmic history, reaching deep into the primordial Universe. At redshifts $z<10^6$, thermalization processes become inefficient and existing limits from COBE/FIRAS imply that no more than $\Delta \rho /\rho <6\times 10^{-5}$ (95% c.l.) of energy could have been injected into the CMB. However, at higher redshifts, when thermalization is efficient, the constraint weakens and $\Delta \rho /\rho \simeq 0.01-0.1$ could in principle have occurred. Existing computations for the evolution of distortions commonly assume $\Delta \rho /\rho \ll 1$ and thus become inaccurate in this case. Similarly, relativistic temperature corrections become relevant for large energy release, but have previously not been modeled as carefully. Here we study the evolution of distortions and the thermalization process after single large energy release at $z>10^5$. We show that for large distortions the thermalization efficiency is significantly reduced and that the distortion visibility is sizeable to much earlier times. This tightens spectral distortions constraints on low-mass primordial black holes with masses $M_{\mathrm{PBH}}<6\times 10^{11}$ g. Similarly, distortion limits on the amplitude of the small-scale curvature power spectrum at wavenumbers $k>10^4{\mathrm{Mpc}}^{-1}$ and short-lived decaying particles with lifetimes $t_X<10^7$ s are tightened, however, these still require a more detailed time-dependent treatment. We also briefly discuss the constraints from measurements of the effective number of relativistic degrees of freedom and light element abundances and how these complement spectral distortion limits.

    ↳ astro-ph.COgr-qchep-phhep-thMNRAS(2020)·65 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.