Mon·Mar 2, 2020Monday·March 2, 2020

1. 01*

   Influence of hadronic resonances on the chemical freeze-out in heavy-ion collisions

   P. Alba🇩🇪 · V. Mantovani Sarti🇩🇪 · J. Noronha-Hostler🇺🇸 · P. Parotto🇺🇸 · I. Portillo-Vazquez🇺🇸 · C. Ratti🇺🇸 · J. M. Stafford🇺🇸

   Detailed knowledge of the hadronic spectrum is still an open question, which has phenomenological consequences on the study of heavy-ion collisions. A previous lattice QCD study concluded that additional strange resonances are missing in the currently tabulated lists provided by the Particle Data Group (PDG). That study identified the list labeled PDG2016+ as the ideal spectrum to be used as an input in thermal-model-based analyses. In this work, we determine the effect of additional resonances on the freeze-out parameters of systems created in heavy-ion collisions. These parameters are obtained from thermal fits of particle yields and net-particle fluctuations. For a complete picture, we compare several hadron lists including both experimentally discovered and theoretically predicted states. We find that the inclusion of additional resonances mildly influences the extracted parameters -- with a general trend of progressively lowering the temperature -- but is not sufficient to close the gap in temperature between light and strange hadrons previously observed in the literature.

   hep-phnucl-thPRC(2020)·52 citations
2. 02*

   Renormalons in integrated spectral function moments and ${\alpha }_s$ extractions

   D. Boito🇧🇷 · F. Oliani🇧🇷

   Precise extractions of ${\alpha }_s$ from $\tau \to (\mathrm{hadrons})+{\nu }_{\tau }$ and from $e^{+}{e}^{-}\to (\mathrm{hadrons})$ below the charm threshold rely on finite energy sum rules (FESRs) where the experimental side is given by integrated spectral function moments. Here we study the renormalons that appear in the Borel transform of polynomial moments in the large-${\beta }_0$ limit and in full QCD. In large-${\beta }_0$, we establish a direct connection between the renormalons and the perturbative behaviour of moments often employed in the literature. The leading IR singularity is particularly prominent and is behind the fate of moments whose perturbative series are unstable, while those with good perturbative behaviour benefit from partial cancellations of renormalon singularities. The conclusions can be extended to QCD through a convenient scheme transformation to the $C$-scheme together with the use of a modified Borel transform which make the results particularly simple; the leading IR singularity becomes a simple pole, as in large-${\beta }_0$. Finally, for the moments that display good perturbative behaviour, we discuss an optimized truncation based on renormalisation scheme (or scale) variation. Our results allow for a deeper understanding of the perturbative behaviour of integrated spectral function moments and provide theoretical support for low-$Q^2$ ${\alpha }_s$ determinations.

   hep-phPRD(2020)·20 citations
3. 03*

   The dijet mass distribution in heavy ion collisions

   Jared Reiten🇺🇸

   In these proceedings, we review the production of both light and heavy flavor dijets in heavy ion collisions and highlight a promising observable to expose their distinct signatures. We propose the modification of dijet invariant mass distributions in heavy ion collisions as a novel observable that exhibits striking sensitivity to the quark-gluon plasma transport properties and heavy quark mass effects on in-medium parton showers. This observable has the advantage of amplifying the effects of jet quenching in contrast to conventional observables, such as the dijet momentum imbalance shift, which involve cancellations of such effects and, hence, result in less pronounced signals. Predictions are presented for Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV to guide the future sPHENIX program at the Relativistic Heavy Ion Collider.

   hep-phhep-exnucl-exnucl-thEPJ Web Conf.(2020)·0 citations
4. 04*

   Behavior of Cross Sections for Large Numbers of Particles

   Michael Dine🇺🇸 · Hiren H. Patel🇺🇸 · Jaryd F. Ulbricht🇺🇸

   It has been suggested that scattering cross sections at very high energies for producing large numbers of Higgs particles may exhibit factorial growth, and that curing this growth might be relevant to other questions in the Standard Model. We point out, first, that the question is inherently non-perturbative; low orders in the formal perturbative expansion do not give a good approximation to the scattering amplitude for sufficiently large N for any fixed, small value of the coupling. Focusing on $\lambda {\varphi }^4$ theory, we argue that there may be a systematic approximation scheme for processes where N particles near threshold scatter to produce N particles, and discuss the leading contributions to the scattering amplitude and cross sections in this limit. Scattering amplitudes do not grow as rapidly as in perturbation theory. Additionally, partial and total cross sections do not show factorial growth. In the case of cross sections for $2\to N$ particles, there is no systematic large N approximation available. That said, we provide evidence that non-perturbatively, there is no factorial growth in partial or total cross sections.

   hep-phhep-th11 citations
5. 05*

   Massive Spin-2 Scattering Amplitudes in Extra-Dimensional Theories

   R. Sekhar Chivukula🇺🇸 · Dennis Foren🇺🇸 · Kirtimaan A. Mohan🇺🇸 · Dipan Sengupta🇺🇸 · Elizabeth H. Simmons🇺🇸

   In this paper we describe in detail the computation of the scattering amplitudes of massive spin-2 Kaluza-Klein excitations in a gravitational theory with a single compact extra dimension, whether flat or warped. These scattering amplitudes are characterized by intricate cancellations between different contributions: although individual contributions may grow as fast as $\mathcal{O}(s^5)$, the full results grow only as $\mathcal{O}(s)$. We demonstrate that the cancellations persist for all incoming and outgoing particle helicities and examine how truncating the computation to only include a finite number of intermediate states impacts the accuracy of the results. We also carefully assess the range of validity of the low energy effective Kaluza-Klein theory. In particular, for the warped case we demonstrate directly how an emergent low energy scale controls the size of the scattering amplitude, as conjectured by the AdS/CFT correspondence.

   hep-phgr-qchep-thPRD(2020)·45 citations
6. 06*

   ISR and IFI in Precision AFB Studies with KKMC-hh

   S. Yost🇺🇸 · S. Jadach · B.F.L. Ward🇺🇸 · Z. Was

   KKMC-hh is a hadronic event generator for Z boson production and decays, which includes exponentiated multi-photon radiation and first-order electroweak corrections. We have used KKMC-hh to investigate the role of initial sate radiation (ISR) and initial-final interference (IFI) in precision electroweak analyses at the LHC. We compare the effect of this radiation on angular distributions and forward-backward asymmetry, which are particularly important for the measurement of the weak mixing angle. We discuss the relation of the ISR implementation in KKMC-hh to ISR from parton distribution functions with QED corrections.

   hep-phPoS(2019)·7 citations
7. 07*

   Flavor physics and Jarlskog determinant

   Jihn E. Kim🇰🇷

   The flavor problem is reviewed starting with the chiral symmetry, and the $A_4$ symmetry derivation and its realization in GUTs are presented.

   hep-ph1 citation
8. 08*

   Current status and muon $g-2$ explanation of lepton portal dark matter

   Junichiro Kawamura🇺🇸 · Shohei Okawa🇨🇦 · Yuji Omura🇯🇵

   In this paper, we summarize phenomenology in lepton portal dark matter (DM) models, where DM couples to leptons and extra leptons/sleptons. There are several possible setups: complex/real scalar DM and Dirac/Majorana fermion DM. In addition, there are choices for the lepton chirality that couples to DM. We discuss the prediction of each model and compare it with the latest experimental constraints from the DM, the LHC, and the flavor experiments. We also propose a simple setup to achieve the discrepancy in the anomalous magnetic moment of muon.

   hep-phastro-ph.COastro-ph.HEhep-exJHEP(2020)·64 citations
9. 09*

   Getting chirality right: single scalar leptoquark solutions to the $(g-2{)}_{e,\mu }$ puzzle

   Innes Bigaran🇦🇺 · Raymond R. Volkas🇦🇺

   We identify the two scalar leptoquarks capable of generating sign-dependent contributions to leptonic magnetic moments, $R_2\sim (3,2,7/6)$ and $S_1\sim (3,1,-1/3)$, as favoured by current measurements. We consider the case in which the electron and muon sectors are decoupled, and real-valued Yukawa couplings are specified using an up-type quark mass-diagonal basis. Contributions to $\Delta a_e$ arise from charm-containing loops and $\Delta a_{\mu }$ from top-containing loops -- hence avoiding dangerous LFV constraints, particularly from $\mu \to e\gamma$. The strongest constraints on these models arise from contributions to the Z leptonic decay widths, high-$p_T$ leptonic tails at the LHC, and from (semi)leptonic kaon decays. To be a comprehensive solution to the $(g-2{)}_{e/\mu }$ puzzle we find that the mass of either leptoquark must be $\lesssim 65$ TeV. This analysis can be embedded within broader flavour anomaly studies, including those of hierarchical leptoquark coupling structures. It can also be straightforwardly adapted to accommodate future measurements of leptonic magnetic moments, such as those expected from the Muon $g-2$ collaboration in the near future.

   hep-phPRD(2020)·109 citations
10. 10*

    Enhancing Scalar Productions with Leptoquarks at the LHC

    Arvind Bhaskar🇮🇳 · Debottam Das🇮🇳 · Bibhabasu De🇮🇳 · Subhadip Mitra🇮🇳

    The Standard Model (SM), when extended with a leptoquark (LQ) and right-handed neutrinos, can have interesting new implications for Higgs physics. We show that sterile neutrinos can induce a boost to the down-type quark Yukawa interactions through a diagonal coupling associated with the quarks and a scalar LQ of electromagnetic charge $1/3$. The relative change is moderately larger in the case of the first two generations of quarks, as they have vanishingly small Yukawa couplings in the SM. The enhancement in the couplings would also lead to a non-negligible contribution from the quark fusion process to the production of the 125 GeV Higgs scalar in the SM, though the gluon fusion always dominates. However, this may not be true for a general scalar. As an example, we consider a scenario with a SM-gauge-singlet scalar $\varphi$ where an $\mathcal{O}(1)$ coupling between $\varphi$ and the LQ is allowed. The $\varphi q\bar{q}$ Yukawa couplings can be generated radiatively only through a loop of LQ and sterile neutrinos. Here, the quark fusion process can have a significant cross section, especially for a light $\varphi$. It can even supersede the normally dominant gluon fusion process for a moderate to large value of the LQ mass. This model can be tested/constrained at the high luminosity run of the LHC through a potentially large branching fraction of the scalar to two jets.

    hep-phhep-exPRD(2020)·38 citations
11. 11*

    Exclusive photoproduction of vector meson at next-to-leading order from Color Glass Condensate

    Yanbing Cai🇨🇳 · Wenchang Xiang🇨🇳 · Mengliang Wang🇨🇳 · Daicui Zhou🇨🇳

    The exclusive photoproduction of vector mesons ($J/\psi$ and $\varphi$) are investigated by taking into account the next-to-leading order corrections in the framework of Color Glass Condensate. We confront the next-to-leading order modified dipole amplitude with the HERA data finding good agreement. Our studies show that the ${\chi }^2/d.o.f$ from leading order, running coupling and collinearly improved next-to-leading order dipole amplitudes are 2.159, 1.097, and 0.932 for the elastic cross section, and 2.056, 1.449, and 1.357 for differential cross section. The outcomes indicate that the higher-order corrections have a significant contribution to the vector meson productions and the description of the experimental data is dramatically improved once the higher order corrections are included. We extend the next-to-leading order exclusive vector meson production model to LHC energies by using the same parameters obtained from HERA. We find that our model can also give a rather good description of the $J/\psi$ and $\varphi$ data in proton-proton collision at 7 TeV and 13 TeV at LHCb experiments.

    hep-phCPC(2020)·15 citations
12. 12*

    Supersoft Stops

    Timothy Cohen🇺🇸 · Nathaniel Craig🇺🇸 · Seth Koren🇺🇸 · Matthew McCullough🇨🇭 · Joseph Tooby-Smith🇬🇧

    In a supersymmetric (SUSY) theory, the IR-contributions to the Higgs mass are calculable below the mediation scale ${\Lambda }_{\text{UV}}$ in terms of the IR field content and parameters. However, logarithmic sensitivity to physics at ${\Lambda }_{\text{UV}}$ remains. In this work we present a first example of a framework, dictated by symmetries, to supersoften these logarithms from the matter sector. The result is a model with finite, IR-calculable corrections to the Higgs mass. This requires the introduction of new fields -- the `lumberjacks' -- whose role is to screen the UV-sensitive logs. These models have considerably reduced fine-tuning, by more than an order of magnitude for high scale supersymmetry. This impacts interpretations of the natural parameter space, suggesting it may be premature to declare a naturalness crisis for high-scale SUSY.

    hep-phPRL(2020)·9 citations
13. 13*

    On the reduction of negative weights in MC@NLO-type matching procedures

    R. Frederix🇸🇪 · S. Frixione🇮🇹 · S. Prestel🇸🇪 · P. Torrielli🇮🇹

    We show how a careful analysis of the behaviour of a parton shower Monte Carlo in the vicinity of the soft and collinear regions allows one to formulate a modified MC@NLO-matching prescription that reduces the number of negative-weight events with respect to that stemming from the standard MC@NLO procedure. As a first practical application of such a prescription, that we dub MC@NLO-$\Delta$, we have implemented it in the MadGraph5_aMC@NLO framework, by employing the Pythia8 Monte Carlo. We present selected MC@NLO-$\Delta$ results at the 13 TeV LHC, and compare them with MC@NLO ones. We find that the former predictions are consistent with the latter ones within the typical matching systematics, and that the reduction of negative-weight events is significant.

    hep-phJHEP(2020)·64 citations
14. 14*

    Probing $\mu \tau$ flavor-violating solutions for the muon $g-2$ anomaly at Belle II

    Syuhei Iguro🇯🇵 · Yuji Omura🇯🇵 · Michihisa Takeuchi🇯🇵

    The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the $\mu \tau$ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the $\tau$ mass enhancement in the one-loop correction. In this paper, we study the signal of this model, i.e. the same-sign leptons, in the Belle II experiment, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensitive to the scenario in the mediator mass range of $\mathcal{O}(1-10)$~GeV, using the $e^{+}{e}^{-}\to {\mu }^{\pm }{\tau }^{\mp }X\to {\mu }^{\pm }{\mu }^{\pm }{\tau }^{\mp }{\tau }^{\mp }$ process induced by the $X$.

    hep-phJHEP(2020)·45 citations
15. 15*

    Quark masses: N3LO bridge from $RI/SMOM$ to $\overline{\mathrm{MS}}$ scheme

    Alexander Bednyakov🇷🇺 · Andrey Pikelner🇷🇺

    We analytically compute the three-loop corrections to the relation between the renormalized quark masses defined in the minimal-subtraction ($\overline{\mathrm{MS}}$) and the regularization-invariant symmetric momentum-subtraction ($RI/SMOM$) schemes. Our result is valid in the Landau gauge and can be used to reduce the uncertainty in a lattice determination of the $\overline{\mathrm{MS}}$ quark masses.

    hep-phhep-lathep-thPRD(2020)·19 citations
16. 16*

    Dark matter self-interactions from spin-2 mediators

    Yoo-Jin Kang🇰🇷 · Hyun Min Lee🇰🇷

    We propose a new mechanism for rendering dark matter self-interacting in the presence of a massive spin-2 mediator. The derived Yukawa-type potential for dark matter is independent of the spins of dark matter in the leading order of the momentum expansion, so are the resulting non-perturbative effects for the dark matter self-scattering. We find that both the Born cross section and relatively mild resonance effects assist to make the self-scattering cross section velocity-dependent. We discuss how to evade the current indirect bounds on dark matter annihilations and show that the model is marginally compatible with perturbative unitarity in the ghost-free realization of the massive spin-2 particle.

    hep-phastro-ph.COhep-thEPJC(2021)·22 citations
17. 17*

    Non-perturbative contributions to vector-boson transverse momentum spectra in hadronic collisions

    Francesco Hautmann🇧🇪 · Ignazio Scimemi🇪🇸 · Alexey Vladimirov🇩🇪

    Experimental measurements of Drell-Yan (DY) vector-boson production are available from the Large Hadron Collider (LHC) and from lower-energy collider and fixed-target experiments. In the region of low vector-boson transverse momenta $q_T$, which is important for the extraction of the $W$-boson mass at the LHC, QCD contributions from non-perturbative Sudakov form factors and intrinsic transverse momentum distributions become relevant. We study the potential for determining such contributions from fits to LHC and lower-energy experimental data, using the framework of low-$q_T$ factorization for DY differential cross sections in terms of transverse momentum dependent (TMD) distribution functions. We investigate correlations between different sources of TMD non-perturbative effects, and correlations with collinear parton distributions. We stress the relevance of accurate DY measurements at low masses and with fine binning in transverse momentum for improved determinations of long-distance contributions to Sudakov evolution processes and TMDs.

    hep-phPLB(2020)·64 citations
18. 18*

    Charge-dependent flow induced by electromagnetic fields in heavy ion collisions

    U. Gürsoy🇳🇱 · D.E. Kharzeev🇺🇸 · E. Marcus🇳🇱 · K. Rajagopal🇺🇸 · C. Shen🇺🇸

    The colliding heavy ions create extremely strong magnetic and electric fields that significantly affect the evolution of the produced quark-gluon plasma (QGP). The knowledge of these fields is essential for establishing the role of topological fluctuations in the QGP through the chiral magnetic effect and related anomaly-induced phenomena. In this talk, we describe our work on the evolution of the QGP in electric and magnetic fields in the framework of hydrodynamics supplemented, in a perturbative fashion, by the dynamical electromagnetism. The evolution of the QGP fluid is described within the iEBE-VISHNU framework. We find that the electromagnetically induced currents result in a charge-odd directed flow $\Delta v_1$ and a charge-odd $\Delta v_3$ flow both of which are odd in rapidity. While the predicted magnitude of these charge-odd flows agrees with the data from RHIC and LHC, the sign of the predicted asymmetry between the flows of positive and negative hadrons is opposite to the data.

    hep-phnucl-exnucl-thNPA(2021)·4 citations
19. 19*

    Triangle singularity in $B^{-}\to K^{-}X(3872);X\to {\pi }^0{\pi }^{+}{\pi }^{-}$ and the X(3872) mass

    Raquel Molina🇪🇸 · Eulogio Oset🇪🇸

    We evaluate the contribution to the $X(3872)$ width from a triangle mechanism in which the $X$ decays into $D^{\ast 0}{\bar{D}}^0-cc$, then the $D^{\ast 0}({\bar{D}}^{\ast 0})$ decays into $D^0{\pi }^0$ (${\bar{D}}^0{\pi }^0$) and the $D^0{\bar{D}}^0$ fuse to produce ${\pi }^{+}{\pi }^{-}$. This mechanism produces an asymmetric peak from a triangle singularity in the ${\pi }^{+}{\pi }^{-}$ invariant mass with a shape very sensitive to the $X$ mass. We evaluate the branching ratios for a reaction where this effect can be seen in the $B^{-}\to K^{-}{\pi }^0{\pi }^{+}{\pi }^{-}$ reaction and show that the determination of the peak in the invariant mass distribution of ${\pi }^{+}{\pi }^{-}$ is all that is needed to determine the $X$ mass. Given the present uncertainties in the $X$ mass, which do not allow to know whether the $D^{\ast 0}{\bar{D}}^0$ state is bound or not, measurements like the one suggested here should be most welcome to clarify this issue.

    hep-phEPJC(2020)·30 citations
20. 20*

    Addressing $R_{D^{(\ast )}}$, $R_{K^{(\ast )}}$, muon $g-2$ and ANITA anomalies in a minimal $R$-parity violating supersymmetric framework

    Wolfgang Altmannshofer🇺🇸 · P. S. Bhupal Dev🇺🇸 · Amarjit Soni🇺🇸 · Yicong Sui🇺🇸

    We analyze the recent hints of lepton flavor universality violation in both charged-current and neutral-current rare decays of $B$-mesons in an $R$-parity violating supersymmetric scenario. Motivated by simplicity and minimality, we had earlier postulated the third-generation superpartners to be the lightest (calling the scenario "RPV3") and explicitly showed that it preserves gauge coupling unification and of course has the usual attribute of naturally addressing the Higgs radiative stability. Here we show that both $R_{D^{(\ast )}}$ and $R_{K^{(\ast )}}$ flavor anomalies can be addressed in this RPV3 framework. Interestingly, this scenario may also be able to accommodate two other seemingly disparate anomalies, namely, the longstanding discrepancy in the muon $(g-2)$, as well as the recent anomalous upgoing ultra-high energy ANITA events. Based on symmetry arguments, we consider three different benchmark points for the relevant RPV3 couplings and carve out the regions of parameter space where all (or some) of these anomalies can be simultaneously explained. We find it remarkable that such overlap regions exist, given the plethora of precision low-energy and high-energy experimental constraints on the minimal model parameter space. The third-generation superpartners needed in this theoretical construction are all in the 1-10 TeV range, accessible at the LHC and/or next-generation hadron collider. We also discuss some testable predictions for the lepton-flavor-violating decays of the tau-lepton and $B$-mesons for the current and future $B$-physics experiments, such as LHCb and Belle II. Complementary tests of the flavor anomalies in the high-$p_T$ regime in collider experiments such as the LHC are also discussed.

    hep-phhep-exPRD(2020)·113 citations
21. 21*

    New Limits on Coloured Three Jet Resonances

    Hassan Easa🇨🇦 · Thomas Gregoire🇨🇦 · Daniel Stolarski🇨🇦

    We consider experimental limits on colour triplet fermions that decay dominantly to three jets via a scalar mediator that can be on- or off-shell. These fermions arise in top-partner models that can solve the hierarchy problem, and limits on this scenario are weaker than those on traditional top-partner models because of the messy all-hadronic final state with significant backgrounds. We do find, however, that while there are no dedicated searches for this scenario, especially in case of an on-shell mediator, the suite of LHC all-hadronic searches still constrains a significant portion of the parameter space. In particular, we find that searches for pair production of di-jet and tri-jet resonances are complementary, covering different regions of parameter space. We also find that if the final state is rich in b-jets, current limits do not change significantly relative to the scenario with all light jets, and we describe how modifications of current search strategies can improve limits in that case.

    hep-phJHEP(2020)·5 citations
22. 22*

    Systematizing the Effective Theory of Self-Interacting Dark Matter

    Prateek Agrawal🇺🇸 · Aditya Parikh🇺🇸 · Matthew Reece🇺🇸

    If dark matter has strong self-interactions, future astrophysical and cosmological observations, together with a clearer understanding of baryonic feedback effects, might be used to extract the velocity dependence of the dark matter scattering rate. To interpret such data, we should understand what predictions for this quantity are made by various models of the underlying particle nature of dark matter. In this paper, we systematically compute this function for fermionic dark matter with light bosonic mediators of vector, scalar, axial vector, and pseudoscalar type. We do this by matching to the nonrelativistic effective theory of self-interacting dark matter and then computing the spin-averaged viscosity cross section nonperturbatively by solving the Schrodinger equation, thus accounting for any possible Sommerfeld enhancement of the low-velocity cross section. In the pseudoscalar case, this requires a coupled-channel analysis of different angular momentum modes. We find, contrary to some earlier analyses, that nonrelativistic effects only provide a significant enhancement for the cases of light scalar and vector mediators. Scattering from light pseudoscalar and axial vector mediators is well described by tree-level quantum field theory.

    hep-phastro-ph.COastro-ph.GAJHEP(2020)·30 citations
23. 23*

    The Full Color Two-Loop Six-Gluon All-Plus Helicity Amplitude

    Adam R. Dalgleish🇬🇧 · David C. Dunbar🇬🇧 · Warren B. Perkins🇬🇧 · Joseph M.W. Strong🇬🇧

    We present the full color two-loop six-point all-plus Yang-Mills amplitude in compact analytic form. The computation uses four dimensional unitarity and augmented recursion.

    hep-phPRD(2020)·25 citations
24. 24*

    A Generalized Nachtmann Theorem in CFT

    Sandipan Kundu🇺🇸

    Correlators of unitary quantum field theories in Lorentzian signature obey certain analyticity and positivity properties. For interacting unitary CFTs in more than two dimensions, we show that these properties impose general constraints on families of minimal twist operators that appear in the OPEs of primary operators. In particular, we rederive and extend the convexity theorem which states that for the family of minimal twist operators with even spins appearing in the reflection-symmetric OPE of any scalar primary, twist must be a monotonically increasing convex function of the spin. Our argument is completely non-perturbative and it also applies to the OPE of nonidentical scalar primaries in unitary CFTs, constraining the twist of spinning operators appearing in the OPE. Finally, we argue that the same methods also impose constraints on the Regge behavior of certain CFT correlators.

    ↳ hep-thhep-phquant-phJHEP(2020)·18 citations
25. 25*

    Dalitz plots and lineshape of $a_1(1260)$ from a relativistic three-body unitary approach

    Daniel Sadasivan🇺🇸 · Maxim Mai🇺🇸 · Hakan Akdag🇩🇪 · Michael Döring🇺🇸

    We formulate the final state interaction of the $a_1(1260)$ resonance decay in a manifestly three-body unitary parameterization and fit it to the $a_1(1260)$ lineshape measured by the ALEPH experiment. Dalitz plots calculated from this fit are presented. The work demonstrates the feasibility to numerically solve a previously derived amplitude and its generalization to isobars with spin and coupled channels. The model can also be applied to other meson decays and modified for the finite-volume problem as it arises in lattice QCD due to its manifest unitarity.

    ↳ nucl-thhep-phnucl-exPRD(2020)·36 citations
26. 26*

    Unveiling the Galileon in a three-body system : scalar and gravitational wave production

    Philippe Brax🇫🇷 · Lavinia Heisenberg🇨🇭 · Adrien Kuntz🇫🇷

    We consider the prospect of detecting cubic Galileons through their imprint on gravitational wave signals from a triple system. Namely, we consider a massive Black Hole (BH) surrounded by a binary system of two smaller BHs. We assume that the three BHs acquire a conformal coupling to the scalar field whose origin could be due to cosmology or to the galactic environment. In this case, the massive BH has a Vainshtein radius which englobes the smaller ones and suppresses the scalar effects on the motion of the binary system. On the other hand the two binaries can be outside each other's redressed Vainshtein radius calculated in the background of the central BH, allowing for a perturbative treatment of their dynamics. Despite the strong Vainshtein suppression, we find that the scalar effects on the binary system are slightly enhanced with respect to the static case and a significant amount of power can be emitted in the form of the Galileon scalar field, hence actively participating in the inspiralling phase. We compute the modification to the GW phase and show that it can lead to a detectable signal for large enough effective scalar coupling.

    ↳ gr-qcastro-ph.COhep-phJCAP(2020)·14 citations
27. 27*

    Fractal structure of Yang-Mills fields

    Airton Deppman🇧🇷 · Eugenio Megias🇪🇸 · Debora P. Menezes🇧🇷

    The origin of non-extensive thermodynamics in physical systems has been under intense debate for the last decades. Recent results indicate a connection between non-extensive statistics and thermofractals. After reviewing this connection, we analyze how scaling properties of Yang-Mills theory allow the appearance of self-similar structures in gauge fields. The presence of such structures, which actually behave as fractals, allows for recurrent non-perturbative calculations of vertices. It is argued that when a statistical approach is used, the non-extensive statistics is obtained, and the Tsallis entropic index, $q$, is deduced in terms of the field theory parameters. The results are applied to QCD in the one-loop approximation, resulting in a good agreement with the value of $q$ obtained experimentally.

    ↳ hep-thhep-phnucl-thPhys.Scripta(2020)·7 citations
28. 28*

    Machine Learning meets the redshift evolution of the CMB Temperature

    Rubén Arjona🇪🇸

    We present a model independent and non-parametric reconstruction with a Machine Learning algorithm of the redshift evolution of the Cosmic Microwave Background (CMB) temperature from a wide redshift range $z\in \left[0,3\right]$ without assuming any dark energy model, an adiabatic universe or photon number conservation. In particular we use the genetic algorithms which avoid the dependency on an initial prior or a cosmological fiducial model. Through our reconstruction we constrain new physics at late times. We provide novel and updated estimates on the $\beta$ parameter from the parametrisation $\text{T}(z)={\text{T}}_0(1+z{)}^{1-\beta }$, the duality relation $\eta (z)$ and the cosmic opacity parameter $\tau (z)$. Furthermore we place constraints on a temporal varying fine structure constant $\alpha$, which would have signatures in a broad spectrum of physical phenomena such as the CMB anisotropies. Overall we find no evidence of deviations within the $1\sigma$ region from the well established $\Lambda \text{CDM}$ model, thus confirming its predictive potential.

    ↳ astro-ph.COgr-qchep-phJCAP(2020)·38 citations
29. 29*

    CMB-HD: Astro2020 RFI Response

    Neelima Sehgal🇺🇸 · Simone Aiola🇺🇸 · Yashar Akrami🇫🇷 · Kaustuv moni Basu🇩🇪 · Michael Boylan-Kolchin🇺🇸 · Sean Bryan🇺🇸 · Caitlin M Casey🇺🇸 · Sébastien Clesse🇧🇪 · Francis-Yan Cyr-Racine🇺🇸 · Luca Di Mascolo🇩🇪 · Simon Dicker🇺🇸 · Thomas Essinger-Hileman🇺🇸 and 36 other authors

    CMB-HD is a proposed ultra-deep (0.5 uk-arcmin), high-resolution (15 arcseconds) millimeter-wave survey over half the sky that would answer many outstanding questions in both fundamental physics of the Universe and astrophysics. This survey would be delivered in 7.5 years of observing 20,000 square degrees, using two new 30-meter-class off-axis cross-Dragone telescopes to be located at Cerro Toco in the Atacama Desert. Each telescope would field 800,000 detectors (200,000 pixels), for a total of 1.6 million detectors.

    ↳ astro-ph.COastro-ph.IMhep-ph44 citations
30. 30*

    System response to the initial energy-momentum tensor in relativistic heavy-ion collisions

    Jefferson Sousa🇧🇷 · Jorge Noronha🇺🇸 · Matthew Luzum🇧🇷

    The evolution of a relativistic heavy-ion collision is typically understood as a process that transmutes the initial geometry of the system into the final momentum distribution of observed hadrons, which can be described via a cumulant expansion of the initial distribution of energy density and is represented at leading order as the well-known eccentricity scaling of anisotropic flow. We summarize a proposed extension of this framework to include the contribution from initial momentum-space properties, as encoded in other components of the energy-momentum tensor. Numerical tests validate this proposal.

    ↳ nucl-thhep-phNPA(2021)·4 citations
31. 31*

    Detecting dark matter around black holes with gravitational waves: Effects of dark-matter dynamics on the gravitational waveform

    Bradley J. Kavanagh🇳🇱 · David A. Nichols🇺🇸 · Gianfranco Bertone🇳🇱 · Daniele Gaggero🇪🇸

    A dark matter overdensity around a black hole may significantly alter the dynamics of the black hole's merger with another compact object. We consider here intermediate mass-ratio inspirals of stellar-mass compact objects with intermediate-mass black holes "dressed" with dark matter. We first demonstrate that previous estimates based on a fixed dark-matter dress are unphysical for a range of binaries and dark-matter distributions by showing that the total energy dissipated by the compact object through dynamical friction, as it inspirals through the dense dark matter environment towards the black hole, is larger than the gravitational binding energy of the dark-matter dress itself. We then introduce a new formalism that allows us to self-consistently follow the evolution of the dark-matter dress due to its gravitational interaction with the binary. We show that the dephasing of the gravitational waveform induced by dark matter is smaller than previously thought, but is still potentially detectable with the LISA space interferometer. The gravitational waves from such binaries could provide powerful diagnostics of the particle nature of dark matter.

    ↳ gr-qcastro-ph.COhep-phPRD(2020)·256 citations
32. 32*

    VegasFlow: accelerating Monte Carlo simulation across multiple hardware platforms

    Stefano Carrazza🇮🇹 · Juan M. Cruz-Martinez🇮🇹

    We present VegasFlow, a new software for fast evaluation of high dimensional integrals based on Monte Carlo integration techniques designed for platforms with hardware accelerators. The growing complexity of calculations and simulations in many areas of science have been accompanied by advances in the computational tools which have helped their developments. VegasFlow enables developers to delegate all complicated aspects of hardware or platform implementation to the library so they can focus on the problem at hand. This software is inspired on the Vegas algorithm, ubiquitous in the particle physics community as the driver of cross section integration, and based on Google's powerful TensorFlow library. We benchmark the performance of this library on many different consumer and professional grade GPUs and CPUs.

    ↳ physics.comp-phhep-exhep-phstat.MLComput.Phys.Commun.(2020)·38 citations
33. 33*

    FeynGame

    R.V. Harlander🇩🇪 · S.Y. Klein🇩🇪 · M. Lipp🇩🇪

    A java-based graphical tool for drawing Feynman diagrams is presented. It differs from similar existing tools in various respects. For example, it is based on models, consisting of particles (lines) and (optionally) vertices, each of which can be given their individual properties (line style, color, arrows, label, etc.). The diagrams can be exported in any standard image format, or as PDF. Aside from its plain graphical aspect, the goal of FeynGame is also educative, as it can check a Feynman diagrams validity. This provides the basis to play games with diagrams, for example. Here we describe on such game where a given set of initial and final states must be connected through a Feynman diagram within a given interaction model.

    ↳ physics.ed-phhep-phComput.Phys.Commun.(2020)·100 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.