PaperPanorama

HEP Phenomenology·hep-ph

Fri·Feb 24, 2023

27 papers19 primary·8 cross-listed·reconstructed*

  1. 01*

    Several conjectures from the hadron physics: The transient worlds beside(s) ours

    Hua-Xing Chen🇨🇳

    The past decades witnessed the golden era of hadron physics, which gives us a good opportunity to study the physics happening in a transient period of time. The development on the singly heavy baryons indicates that there exists the fine structure of hadron spectrum caused by the direct strong interaction, and the development on the exotic hadrons indicates that the residue strong interaction is capable of forming the hadronic molecules. Similar to the electromagnetic interaction, the strong interaction may be capable of forming some imaginable hadronic worlds. Moreover, there can be various worlds formed by various fundamental physical laws. Some hadrons have so transient lifetimes that they may not even be formed. We discuss whether these non-existent particles are capable of affecting our realistic world. We discuss what kinds of particles exist, and so can be observed, in our realistic world. We conjecture that the ratios () and () can be used to describe the particles existing and not-existing in our realistic world, respectively. Here , , and are the mass, width, and lifetime, respectively. We propose to use the ratio () to describe the particles quasi-existing in our realistic world, whose studies may allow us to go beyond the quantum physics and arrive at another type of boundary of our realistic world, that is from the existent to the non-existent. We propose to investigate the quasi-existent particles by studying the singly heavy baryons through various imperfect symmetries among them. We obtain an incidental conjecture that the lifetime and width may be quantized for the particles existing in our realistic world as \begin{equation*}M\tau=n\hbar/2~~~{\rm{and}}~~~M/\Gamma=n/2\,,~~~n=1,2,3\cdots\,.\end{equation*}

    hep-ph2 citations
  2. 02*

    Strong decay properties of single heavy baryons , and

    Guo-Liang Yu🇨🇳 · Yan Meng🇨🇳 · Zhen-Yu Li🇨🇳 · Zhi-Gang Wang🇨🇳 · Lu Jie🇨🇳

    Motivated by recent progresses in experiments in searching for the baryons, we systematically analyze the strong decay behaviors of single heavy baryons , and . The two-body strong decay properties of -wave, -wave and some -wave states are studied with the model. The results support assigning the recently observed and as the 2S() and 1D() states, respectively. In addition, the quantum numbers of many other experimentally observed baryons are also suggested according to their strong decays. Finally, some baryons which have good potentials to be observed in experiments are predicted and the possible decay channels for searching for these predicted states are also suggested.

    hep-phInt.J.Mod.Phys.A(2023)·24 citations
  3. 03*

    Parton Distribution Functions for discovery physics at the LHC

    A M Cooper-Sarkar🇬🇧

    At the LHC we are colliding protons, but it is not the protons that are doing the interacting. It is their constituents the quarks, antiquarks and gluons-collectively known as partons. We need to know how what fractional momentum of the proton each of these partons takes at the energy scale of LHC collisions, in order to understand LHC physics. Such parton momentum distributions are known as PDFs (Parton Distribution Functions) and are a field of study in their own right. However, it is now the case that the uncertainties on PDFs are a major contributor to the background to the discovery of physics Beyond the Standard Model (BSM). Firstly in searches at the highest energy scales of a few TeV and secondly in precision measurements of Standard Model (SM) parameters such as the mass of the W-boson, , or the weak mixing angle, , which can provide indirect evidence for BSM physics in their deviations from SM values.

    hep-phActa Phys.Polon.Supp.(2023)·3 citations
  4. 04*

    Regeneration of bottomonia in an open quantum systems approach

    Nora Brambilla🇩🇪 · Miguel Ángel Escobedo🇪🇸 · Ajaharul Islam🇺🇸 · Michael Strickland🇺🇸 · Anurag Tiwari🇺🇸 · Antonio Vairo🇩🇪 · Peter Vander Griend🇺🇸

    We demonstrate the importance of quantum jumps in the nonequilibrium evolution of bottomonium states in the quark-gluon plasma. Based on nonrelativistic effective field theory and the open quantum system framework, we evolve the density matrix of color singlet and octet pairs. We show that quantum regeneration of singlet states from octet configurations is necessary to understand experimental results for the suppression of both bottomonium ground and excited states. The values of the heavy-quarkonium transport coefficients used are consistent with recent lattice QCD determinations.

    hep-phhep-exhep-latnucl-ex+1PRD(2023)·51 citations
  5. 05*

    Stability of the next-to-tribimaximal mixings under radiative corrections with the variation of SUSY breaking scale in MSSM

    Kh. Helensana Devi🇮🇳 · K. Sashikanta Singh🇮🇳 · N.Nimai Singh🇮🇳

    We analyse the radiative stability of the next-to-tribimaximal mixings () with the variation of SUSY breaking scale () in MSSM, for both normal ordering (NO) and inverted ordering (IO) at the fixed input value of seesaw scale GeV and two different values of . All the neutrino oscillation parameters receive varying radiative corrections irrespective of the values at the electroweak scale, which are all within range of the latest global fit data at low value of (30). NO is found to be more stable than IO for all four different NTBM mixing patterns.

    hep-phAdv.High Energy Phys.(2023)·0 citations
  6. 06*

    Gluon contribution to the mechanical properties of a dressed quark in light-front Hamiltonian QCD

    Jai More🇮🇳 · Asmita Mukherjee🇮🇳 · Sreeraj Nair🇨🇳 · Sudeep Saha🇮🇳

    We calculate the contribution to the gravitational form factors (GFFs) from the gluon part of the energy-momentum tensor in QCD. We take a simple spin composite state, namely a quark dressed with a gluon. We use the light-front Hamiltonian QCD approach in the light-front gauge. We also present the effect of the gluon on the mechanical properties like the pressure, shear and energy distributions of the dressed quark state.

    hep-phPRD(2023)·21 citations
  7. 07*

    Internal force distributions in 't Hooft-Polyakov monopole and Julia-Zee dyon

    J. Yu. Panteleeva🇩🇪

    The energy-momentum tensor of the 't Hooft-Polyakov monopole and the Julia-Zee dyon are studied. This tensor contains important information about the pressure and the shear force distributions which define the mechanical properties of systems. Obtaining the violation of the local stability criterion for the magnetic monopole and dyon we decompose the EMTs into long- and short-range parts. This decomposition depends on the abelian field strength tensor which can not be uniquely defined. We suggest to use the modified 't Hooft definition for the tensor. Finally, the long- and short-range parts of the EMTs are computed and new equilibrium equations are obtained. Numerical values for masses, -terms and various mean square radii for the monopole and the dyon are also computed.

    hep-phhep-thPRD(2023)·12 citations
  8. 08*

    Constraining Lorentz Invariance Violation with Next-Generation Long-Baseline Experiments

    Sanjib Kumar Agarwalla🇮🇳 · Sudipta Das🇮🇳 · Sadashiv Sahoo🇮🇳 · Pragyanprasu Swain🇮🇳

    Unified theories such as string theory and loop quantum gravity allow the Lorentz Invariance Violation (LIV) at the Planck Scale ( GeV). Using an effective field theory, this effect can be observed at low energies in terms of new interactions with a strength of . These new interactions contain operators with LIV coefficients which can be CPT-violating or CPT-conserving. In this work, we study in detail how these LIV parameters modify the transition probabilities in the next-generation long-baseline experiments, DUNE and T2HK. We evaluate the sensitivities of these experiments in isolation and combination to constrain the off-diagonal CPT-violating (, , ) and CPT-conserving (, , ) LIV parameters. We derive approximate compact analytical expressions of and probabilities in the presence of these LIV parameters to explain our numerical results. We explore the possible correlations and degeneracies between these LIV parameters & 3 parameters & . We find that for non-maximal values of , there exist degenerate solutions in its opposite octant for standalone DUNE and T2HK. These degeneracies disappear when we combine the data from DUNE and T2HK. In case of no-show, we place the expected bounds on these CPT-violating and CPT-conserving LIV parameters at 95% C.L. using the standalone DUNE, T2HK, and their combination. We observe that due to its access to a longer baseline and high-energy neutrinos, DUNE has a better reach in probing all these LIV parameters as compared to T2HK. Since the terms containing the CPT-conserving LIV parameters are proportional to neutrino energy in oscillation probabilities, T2HK is almost insensitive to the CPT-conserving LIV parameters because it mostly deals with sub-GeV neutrinos.

    hep-phhep-exphysics.ins-detJHEP(2023)·18 citations
  9. 09*

    Nonextensive effects on QCD chiral phase diagram and baryon-number fluctuations within Polyakov-Nambu-Jona-Lasinio model

    Ya-Peng Zhao🇨🇳 · Chao-Yong Wang🇨🇳 · Shu-Yu Zuo🇨🇳 · Cheng-Ming Li🇨🇳

    In this paper, a version of the Polyakov-Nambu-Jona-Lasinio (PNJL) model based on nonextensive statistical mechanics is presented. This new statistics summarizes all possible factors that violate the assumptions of the Boltzmann-Gibbs (BG) statistics to a dimensionless nonextensivity parameter , and when tends to 1, it returns to the BG case. Within the nonextensive PNJL model, we found that as increases, the location of the critical end point (CEP) exhibits non-monotonic behavior. That is, for , CEP moves in the direction of lower temperature and larger quark chemical potential. But for , CEP turns to move in the direction of lower temperature and lower quark chemical potential. In addition, we studied the moments of the net-baryon number distribution, that is, the variance (), skewness (S), and kurtosis (). Our results are generally consistent with the latest experimental data, especially for , when is set to .

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

    Probing chiral-even and chiral-odd leading twist quark generalised parton distributions through the exclusive photoproduction of a pair

    Goran Duplančić🇭🇷 · Saad Nabeebaccus🇫🇷 · Kornelija Passek-Kumerički🇭🇷 · Bernard Pire🇫🇷 · Lech Szymanowski🇵🇱 · Samuel Wallon🇫🇷

    We extend our studies of a new class of exclusive processes using the collinear factorisation framework by considering the exclusive photoproduction of a pair, in the kinematics where the pair has a large invariant mass, {and the outgoing -meson has a sufficiently large transverse momentum to not resonate with the nucleon}. We cover the whole kinematical range from medium energies in fixed target experiments to very large energies of colliders, by considering the experimental conditions of JLab~12-GeV, COMPASS, future EIC and LHC (in ultra-peripheral collisions) cases. One of the main interest in studying the present process is that it provides access to both chiral-even and chiral-odd GPDs, depending on the polarisation of the outgoing -meson, both at leading twist. Our analysis covers both neutral and charged -mesons. We find that the order of magnitude of the obtained cross sections are sufficiently large for a dedicated experimental analysis to be performed, especially at JLab, for both longitudinally and transversely polarised . Furthermore, we compute the linear photon beam polarisation asymmetry {which is} sizeable for a longitudinally polarised meson. These predictions are obtained for both asymptotic distribution amplitude (DA) and the \textit{holographic} DA.

    hep-phhep-exnucl-exnucl-thPRD(2023)·44 citations
  11. 11*

    Pineline: Industrialization of High-Energy Theory Predictions

    Andrea Barontini🇮🇹 · Alessandro Candido🇮🇹 · Juan M. Cruz-Martinez🇨🇭 · Felix Hekhorn🇮🇹 · Christopher Schwan🇩🇪

    We present a collection of tools automating the efficient computation of large sets of theory predictions for high-energy physics. Calculating predictions for different processes often require dedicated programs. These programs, however, accept inputs and produce outputs that are usually very different from each other. The industrialization of theory predictions is achieved by a framework which harmonizes inputs (runcard, parameter settings), standardizes outputs (in the form of grids), produces reusable intermediate objects, and carefully tracks all meta data required to reproduce the computation. Parameter searches and fitting of non-perturbative objects are exemplary use cases that require a full or partial re-computation of theory predictions and will thus benefit of such a toolset. As an example application we present a study of the impact of replacing NNLO QCD K-factors in a PDF fit with the exact NNLO predictions.

    hep-phComput.Phys.Commun.(2024)·35 citations
  12. 12*

    Exact solutions for Vacuum Decay in Unbounded Potentials

    Nikolaos Tetradis (Athens U.)🇬🇷

    The Standard Model Higgs potential may become unbounded from below at large field values, with important cosmological implications. For a potential of this form, the commonly assumed scenario of a nucleated thin-wall bubble driving the transition from the electroweak vacuum to the unstable region does not apply. We present exact analytical solutions for potentials that have the same qualitative form as the Higgs potential. They show that the transition is driven by a thick-wall spherical bubble of true vacuum, with a surface that expands at asymptotically the speed of light. A `crunch' singularity appears in the quasi-AdS interior, with the collapsed region also expanding at asymptotically the speed of light. The singularity is surrounded by a region of trapped surfaces whose boundary forms an apparent horizon. An event horizon separates the singularity from the bubble exterior, so that the expansion of the bubble surface is not affected by the collapse of the interior. The solutions provide exact descriptions of the geometry for thick-wall bubbles and are consistent with the analysis of [1,2] for the Higgs potential.

    hep-phgr-qcPRD(2023)·5 citations
  13. 13*

    Fractional Analytic QCD beyond Leading Order in timelike region

    A.V. Kotikov🇷🇺 · I.A. Zemlyakov🇷🇺

    In this paper we show that, as in the spacelike case, the inverse logarithmic expansion is applicable for all values of the argument of the analytic coupling constant. We present two different approaches, one of which is based primarily on trigonometric functions, and the latter is based on dispersion integrals. The results obtained up to the 5th order of perturbation theory, have a compact form and their acquiring is much easier than the methods that have been used before. As an example, we apply our results to study the Higgs boson decay into a bb pair.

    hep-phPRD(2023)·22 citations
  14. 14*

    Automated Choice for the Best Renormalization Scheme in BSM Models

    S. Heinemeyer🇪🇸 · F. von der Pahlen🇨🇴

    The explorations of models beyond the Standard Model (BSM) naturally involve scans over the unknown BSM parameters. On the other hand, high precision predictions require calculations at the loop-level and thus a renormalization of (some of) the BSM parameters. Often many choices are possible for the renormalization scheme (RS). This concerns the choice of the set of to-be-renormalized parameters out of a larger set of BSM parameters, but can also concern the type of renormalization condition which is chosen for a specific parameter. A given RS can be well suited to yield "stable" and "well behaved" higher-order corrections in one part of the BSM parameter space, but can fail completely in other parts, which may not even be noticed numerically if an isolated parameter point is investigated, or when the higher-order BSM calculations are performed in an automated, not supervised set-up. Consequently, the (automated) exploration of BSM models requires a choice of a good RS {\em before} the calculation is performed. We propose a new method how such a choice can be performed. We demonstrate the feasibility of our new method in the chargino/neutralino sector of the Minimal Supersymmetric Standard Model (MSSM), but stress the general applicability of our method to all types of BSM models.

    hep-phEPJC(2023)·5 citations
  15. 15*

    Inflection-Point Sgoldstino Inflation in no-Scale Supergravity

    C. Pallis🇬🇷

    We propose a modification of no-scale supergravity models which incorporates sgoldstino stabilization and supersymmetry (SUSY) breaking with a tunable cosmological constant by introducing a Kahler potential which yields a kinetic pole of order one. The resulting scalar potential may develop an inflection point, close to which an inflationary period can be realized for subplanckian field values consistently with the observational data. For central value of the spectral index ns, the necessary tuning is of the order of 10^-6, the tensor-to-scalar ratio is tiny whereas the running of ns is around -3x10^-3. Our proposal is compatible with high-scale SUSY and the results of LHC on the Higgs boson mass.

    hep-phastro-ph.COhep-thPLB(2023)·8 citations
  16. 16*

    Unification based on the mysterious cubic-structure grouping of quarks and leptons

    Mohammad Mehrafarin🇮🇷

    We present a unification model based on the well-known but mysterious cubic-structure grouping of quarks and leptons that suggests an underlying symmetry connection deemed explainable by a unified theory. It results in an extension of the Pati-Salam model that consolidates the fermions into two sixteen-dimensional chiral representations of the gauge group. Moreover, the discrete cubic flavor symmetry arbitrarily conjectured in the literature is found here to be implied by the gauge symmetry. Furthermore, the gauge algebra also describes an eleven-dimensional spacetime decomposed into the usual spacetime and the seven-sphere, which is the manifold of unit octonions. This suggests such a spacetime is apt for embracing all elementary particles and their interactions.

    hep-phhep-thPhys.Scripta(2023)·0 citations
  17. 17*

    Tracking axion-like particles at the LHC

    Gonzalo Alonso-Álvarez🇨🇦 · Joerg Jaeckel🇩🇪 · Diego D. Lopes🇧🇷

    Highly boosted axion-like particles decaying into photon pairs are notoriously hard to detect at the LHC. The collimated decay photons cannot be individually reconstructed using only electromagnetic calorimeter information, making the signal less distinguishable from background. In this note we propose a search strategy to address this issue, exploiting the fact that a fraction of the decay photons convert into electron-positron pairs inside the tracking detector. The resulting tracks can be resolved with high resolution, allowing to separate the two collimated photons and resolve a displaced decay vertex. To demonstrate the effectiveness of this approach, we apply it to ALPs in the challenging MeV-GeV range produced via vector boson fusion. We find that such a search could give sensitivity to untested parameter space.

    hep-phhep-exPRD(2026)·18 citations
  18. 18*

    Dispersion relations for hadronic light-by-light scattering in triangle kinematics

    Jan Lüdtke🇦🇹 · Massimiliano Procura🇦🇹 · Peter Stoffer🇨🇭

    We present a new strategy for the dispersive evaluation of the hadronic light-by-light contribution to the anomalous magnetic moment of the muon . The new approach directly applies in the kinematic limit relevant for : one of the photons is treated as an external electromagnetic field with vanishing momentum, so that the kinematics corresponds to a triangle. We derive expressions for the relevant single-particle intermediate states, as well as the tensor decompositions of the two-pion sub-processes that appear in addition to those needed in the established dispersive approach. The existing approach is based on a set of dispersion relations for the hadronic light-by-light tensor in four-point kinematics. At present it is not known how to consistently include in this framework resonant intermediate states of spin 2 or larger, due to the appearance of kinematic singularities that can be traced back to the redundancy of the tensor decomposition. We show that our new approach circumvents this problem and enables dispersion relations in the limit of triangle kinematics that are manifestly free from kinematic singularities, paving the way towards a data-driven evaluation of all relevant exclusive hadronic intermediate states.

    hep-phhep-exhep-latnucl-thJHEP(2023)·38 citations
  19. 19*

    SHAPER: Can You Hear the Shape of a Jet?

    Demba Ba🇺🇸 · Akshunna S. Dogra🇺🇸 · Rikab Gambhir🇺🇸 · Abiy Tasissa🇺🇸 · Jesse Thaler🇺🇸

    The identification of interesting substructures within jets is an important tool for searching for new physics and probing the Standard Model at colliders. Many of these substructure tools have previously been shown to take the form of optimal transport problems, in particular the Energy Mover's Distance (EMD). In this work, we show that the EMD is in fact the natural structure for comparing collider events, which accounts for its recent success in understanding event and jet substructure. We then present a Shape Hunting Algorithm using Parameterized Energy Reconstruction (SHAPER), which is a general framework for defining and computing shape-based observables. SHAPER generalizes N-jettiness from point clusters to any extended, parametrizable shape. This is accomplished by efficiently minimizing the EMD between events and parameterized manifolds of energy flows representing idealized shapes, implemented using the dual-potential Sinkhorn approximation of the Wasserstein metric. We show how the geometric language of observables as manifolds can be used to define novel observables with built-in infrared-and-collinear safety. We demonstrate the efficacy of the SHAPER framework by performing empirical jet substructure studies using several examples of new shape-based observables.

    hep-phcs.NAhep-exmath.NAJHEP(2023)·23 citations
  20. 20*

    Axion-mediated Transport of Fast Radio Bursts Originating in Inner Magnetospheres of Magnetars

    Anirudh Prabhu🇺🇸

    Among magnetar models of Fast Radio Bursts (FRBs), there is ongoing debate about whether the site of coherent radio emission lies within or beyond the light cylinder. We propose a mechanism by which FRBs produced near the magnetar surface are transported out of the magnetosphere by axions, which couple to photons. If the emission site hosts strong accelerating electric fields, a considerable fraction of the FRB energy budget is converted to an axion burst. Once produced, the axion burst free-streams out of the magnetosphere due to the rapidly-decreasing magnetic field. The burst may escape through either the open or closed magnetosphere, while retaining the temporal signature of the original FRB. In the wind region, axions resonantly excite ordinary (O) modes that escape as the plasma density decreases. The radio efficiency of this mechanism satisfies energetics constraints from FRB 121102 for axion-photon coupling strengths that have not been excluded by other astrophysical probes.

    astro-ph.HEhep-phApJL(2023)·15 citations
  21. 21*

    Oscillation probabilities for a PT-symmetric non-Hermitian two-state system

    Jean Alexandre🇬🇧 · Madeleine Dale🇩🇪 · John Ellis🇬🇧 · Robert Mason🇬🇧 · Peter Millington🇬🇧

    There is growing interest in viable quantum theories with PT-symmetric non-Hermitian Hamiltonians, but a formulation of transition matrix elements consistent with positivity and perturbative unitarity has so far proved elusive. This Letter provides such a formulation, which relies crucially on the ability to span the state space in such a way that the interaction and energy eigenstates are orthonormal with respect to the same positive-definite inner product. We apply this non-Hermitian approach to two-neutrino flavour oscillations, and show how it can accommodate the seesaw mechanism.

    quant-phhep-phhep-thJ.Phys.A(2026)·9 citations
  22. 22*

    Elliptic flow of identified hadrons in Au+Au collisions at using the PHSD model

    B. Towseef🇮🇳 · M. Farooq🇮🇳 · V. Bairathi🇨🇱 · B. Waseem🇮🇳 · S. Kabana🇨🇱 · S. Ahmad🇮🇳

    We present elliptic flow () of identified hadrons at mid-rapidity () in Au+Au collisions at using the Parton Hadron String Dynamics (PHSD) model. Transverse momentum () dependence of identified hadron in minimum bias (0-80%) and three different centrality intervals (0-10%, 10-40%, and 40-80%) are presented. A clear centrality dependence of is observed for particles and anti-particles in Au+Au collisions at . We also present dependence of difference () between particles and corresponding antiparticles. A significant difference in values for baryons and anti-baryons is observed. The number of constituent quark (NCQ) scaling of is discussed in Au+Au collisions at . We also present ratio of between the HSD and PHSD modes to explore the effect of hadronic and partonic interactions in the medium. We observe higher in PHSD mode than the HSD mode, which suggests the formation of partonic medium in Au+Au collisions at . These predictions are useful for the interpretation of data measured in Beam Energy Scan (BES) program at RHIC and will be useful for the future Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR).

    nucl-exhep-phnucl-thEPJC(2023)·2 citations
  23. 23*

    Elliptic flow of inclusive charged hadrons in Au+Au collisions at using the PHSD model

    Waseem Bhat🇮🇳 · M. Farooq Mir🇮🇳 · Vipul Bairathi🇨🇱 · Towseef Bhat🇮🇳 · Sonia Kabana🇨🇱 · Shabir Bhat🇮🇳

    Elliptic flow () measurements of inclusive charged hadrons at mid-rapidity ( 1.0) in Au+Au collisions at using the Parton Hadron String Dynamics (PHSD) model are presented as a function of centrality, transverse momentum () and pseudo-rapidity (). The results are obtained using the -sub event plane method with respect to event plane angle () and participant plane angle (). -integrated charged hadron shows a strong centrality dependence in Au+Au collisions at . The eccentricity scaled elliptic flow () also shows centrality dependence. The higher values of in central collisions suggest development of stronger collectivity. The measurements are compared with the results from Au+Au collisions at published by the STAR experiment at RHIC. We also compare results of HSD and PHSD modes of the model to investigate contribution of hadronic and partonic phases of the medium on the measured . The current results serve as a prediction of the collective behavior of the matter produced in baryon rich and moderate temperature conditions for the upcoming Compressed Baryonic Matter (CBM) experiment at the Facility for Antiproton and Ion Research (FAIR). These predictions are also useful for the interpretation of data measured at RHIC Beam Energy Scan (BES) program.

    nucl-exhep-phnucl-thJ.Phys.G(2023)·1 citation
  24. 24*

    The DESY axion search program

    Daniel Heuchel🇩🇪 · Axel Lindner🇩🇪 · Isabella Oceano🇩🇪

    Feebly Interacting Particles (FIPs) might offer the solution to (some of) the open questions beyond the Standard Models of particle physics and cosmology. At DESY in Hamburg, three non-accelerator-based experiments will search for FIPs as dark matter candidates (ALPS II, BabyIAXO) or constituting the dark matter in our home galaxy (MADMAX).

    hep-exhep-ph1 citation
  25. 25*

    Comparison of Affine and Rational Quadratic Spline Coupling and Autoregressive Flows through Robust Statistical Tests

    Andrea Coccaro🇮🇹 · Marco Letizia🇮🇹 · Humberto Reyes-Gonzalez🇮🇹 · Riccardo Torre🇮🇹

    Normalizing flows have emerged as a powerful brand of generative models, as they not only allow for efficient sampling of complicated target distributions but also deliver density estimation by construction. We propose here an in-depth comparison of coupling and autoregressive flows, both based on symmetric (affine) and non-symmetric (rational quadratic spline) bijectors, considering four different architectures: real-valued non-Volume preserving (RealNVP), masked autoregressive flow (MAF), coupling rational quadratic spline (C-RQS), and autoregressive rational quadratic spline (A-RQS). We focus on a set of multimodal target distributions of increasing dimensionality ranging from 4 to 400. The performances were compared by means of different test statistics for two-sample tests, built from known distance measures: the sliced Wasserstein distance, the dimension-averaged one-dimensional Kolmogorov--Smirnov test, and the Frobenius norm of the difference between correlation matrices. Furthermore, we included estimations of the variance of both the metrics and the trained models. Our results indicate that the A-RQS algorithm stands out both in terms of accuracy and training speed. Nonetheless, all the algorithms are generally able, without too much fine-tuning, to learn complicated distributions with limited training data and in a reasonable time of the order of hours on a Tesla A40 GPU. The only exception is the C-RQS, which takes significantly longer to train, does not always provide good accuracy, and becomes unstable for large dimensionalities. All algorithms were implemented using \textsc{TensorFlow2} and \textsc{TensorFlow Probability} and have been made available on \href{https://github.com/NF4HEP/NormalizingFlowsHD}{GitHub}.

    stat.MLcs.LGhep-exhep-phSymmetry(2024)·16 citations
  26. 26*

    From inclusive to semi-inclusive one-nucleon knockout in neutrino event generators

    Alexis Nikolakopoulos🇺🇸 · Steven Gardiner🇺🇸 · Afroditi Papadopoulou🇺🇸 · Stephen Dolan🇨🇭 · Raúl González-Jiménez🇪🇸

    In neutrino event generators, for models for neutrino and electron scattering only inclusive cross sections are implemented. When these models are used to describe a semi-inclusive cross section, the event generator attaches the hadron variables based on some assumptions. In this work we compare the nucleon kinematics given by the method used in the GENIE event generator, e.g. in the implementation of the SuSAv2 model, to a fully unfactorized calculation using the relativistic distorted wave impulse approximation (RDWIA). We focus on kinematics relevant to the analysis and show that observables obtained with RDWIA differ significantly from those of the approximate method used in GENIE, the latter should be considered unrealistic.

    nucl-thhep-phPhys.Sci.Forum(2023)·11 citations
  27. 27*

    Stringy Dynamics from an Amplitudes Bootstrap

    Clifford Cheung🇺🇸 · Grant N. Remmen🇺🇸

    We describe an analytic procedure whereby scattering amplitudes are bootstrapped directly from an input mass spectrum and a handful of physical constraints: crossing symmetry, boundedness at high energies, and finiteness of exchanged spins. For an integer spectrum, this procedure gives a first principles derivation of a new infinite parameter generalization of the Veneziano amplitude that is unitary while exhibiting dual resonance and consistent high-energy behavior. Lifting to a -deformed integer spectrum, we derive the Coon amplitude and its analogous generalizations. Finally, we apply this logic to derive an infinite class of deformed Virasoro-Shapiro amplitudes.

    hep-thhep-phPRD(2023)·62 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.