Quantum Chromodynamics and Particle Interactions

PYTHIA 6.4 physics and manual

A Model of Leptons

Received 17 October 1967DOI:https://doi.org/10.1103/PhysRevLett.19.1264©1967 American Physical Society

New parton distributions for collider physics

We extract new parton distribution functions (PDFs) of the proton by global analysis of hard scattering data in the general-mass framework of perturbative quantum chromodynamics. Our analysis includes new theoretical developments together with the most recent collider data from deep-inelastic scattering, vector boson production, and single-inclusive jet production. Because of the difficulty in fitting both the D0 Run-II $W$ lepton asymmetry data and some fixed-target DIS data, we present two families of PDFs, CT10 and CT10W, without and with these high-luminosity $W$ lepton asymmetry data included in the global analysis. With both sets of PDFs, we study theoretical predictions and uncertainties for a diverse selection of processes at the Fermilab Tevatron and the CERN Large Hadron Collider.

Relations among Total Cross Sections at High Energies

Progress of Theoretical Physics Vol. 28 No. 6 (1962) pp. 1048–1058 The Hypothesis of Regge Poles and High Energy Nucleon-Nucleon Scattering Yasuo Hara Progress of Theoretical Physics Vol. 29 No. 6 (1963) pp. 851–864 Application of Regge Hypothesis to Multiple Meson Production Mahiko Suzuki Progress of Theoretical Physics Supplement No.51 (1972) pp. 96–228 Regge Pole Model and Hadron Physics Yasuo Hara

Diffusion model approach to simulating electron-proton scattering events

Generative artificial intelligence is a fast-growing area of research offering various avenues for exploration in high-energy nuclear physics. In this work, we explore the use of generative models for simulating electron-proton collisions relevant to experiments like the Continuous Electron Beam Accelerator Facility and the future Electron-Ion Collider (EIC). These experiments play a critical role in advancing our understanding of nucleons and nuclei in terms of quark and gluon degrees of freedom. The use of generative models for simulating collider events faces several challenges such as the sparsity of the data, the presence of global or eventwide constraints, and steeply falling particle distributions. In this work, we focus on the implementation of diffusion models for the simulation of electron-proton scattering events at EIC energies. Our results demonstrate that diffusion models can reproduce relevant observables such as momentum distributions and correlations of particles, momentum sum rules, and the leading electron kinematics, all of which are of particular interest in electron-proton collisions. Although the sampling process is relatively slow compared to other machine-learning architectures, we find diffusion models can generate high-quality samples. We foresee various applications of our work including inference for nuclear structure, interpretable generative machine learning, and searches of physics beyond the Standard Model. Published by the American Physical Society 2024

On the Excited States of Even-even Nuclei

Progress of Theoretical Physics Vol. 15 No. 4 (1956) pp. 416–417:Note on the Nuclear Level of SPin 2+ Mitsuo Sakai Progress of Theoretical Physics Vol. 15 No. 5 (1956) pp. 445–460:Proposal for Experiments for Determination of Beta-Decay Interaction and Theory of Triple Cascade Transition Masato Morita

Is infrared-collinear safe information all you need for jet classification?

A bstract Machine learning-based jet classifiers are able to achieve impressive tagging performance in a variety of applications in high-energy and nuclear physics. However, it remains unclear in many cases which aspects of jets give rise to this discriminating power, and whether jet observables that are tractable in perturbative QCD such as those obeying infrared-collinear (IRC) safety serve as sufficient inputs. In this article, we introduce a new classifier, Jet Flow Networks (JFNs), in an effort to address the question of whether IRC unsafe information provides additional discriminating power in jet classification. JFNs are permutation-invariant neural networks (deep sets) that take as input the kinematic information of reconstructed subjets. The subjet radius and a cut on the subjet’s transverse momenta serve as tunable hyperparameters enabling a controllable sensitivity to soft emissions and nonperturbative effects. We demonstrate the performance of JFNs for quark vs. gluon and Z vs. QCD jet tagging. For small subjet radii and transverse momentum cuts, the performance of JFNs is equivalent to the IRC-unsafe Particle Flow Networks (PFNs), demonstrating that infrared-collinear unsafe information is not necessary to achieve strong discrimination for both cases. As the subjet radius is increased, the performance of the JFNs remains essentially unchanged until physical thresholds that we identify are crossed. For relatively large subjet radii, we show that the JFNs may offer an increased model independence with a modest tradeoff in performance compared to classifiers that use the full particle information of the jet. These results shed new light on how machines learn patterns in high-energy physics data.

Regge Pole Model and Hadron Physics

The Regge pole model of hadron physics is surveyed. Kinematical properties of helicity amplitudes (symmetry properties, crossing relations and analyticity properties), Reggeization of helicity amplitudes, the MacDowell symmetry and the factorization of Regge residues are discussed. We also study the Pomeron, the vector- and tensor-trajectories and the pseudoscalar trajectories. Inclusive reactions in the Regge pole model are briefly discussed.

Magnetic structure of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>A</mml:mi> <mml:mo>≤</mml:mo> <mml:mn>10</mml:mn> </mml:mrow> </mml:math> nuclei using the Norfolk nuclear models with quantum Monte Carlo methods

This paper presents a new detailed study of magnetic moments and form factors of nuclei with mass number $A$ up to 10, based on $a\phantom{\rule{0}{0ex}}b$-$i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ approaches and chiral effective field theory. The results of quantum Monte Carlo calculations for elastic magnetic form factors show excellent agreement with experimental data out to momentum transfers $q\ensuremath{\approx}3$ fm${}^{\ensuremath{-}1}$. Benchmarking such electroweak current models against available data over a wide range of kinematics allows for accurate predictions, which are very important to disentangle signals of new physics from nuclear physics effects.

<i>S</i><i>U</i>(3) Chiral Dynamics

Progress of Theoretical Physics Vol. 39 No. 2 (1968) pp. 405-410 Chiral Dynamics for Photo-Hadron and Weak Interactions Syurei Iwao Progress of Theoretical Physics Vol. 39 No. 6 (1968) pp. 1527-1530 Compton Scattering of Isovector Photons with Nucleons and Algebra of Fields Masaaki Kato and Ken Kawarabayashi Progress of Theoretical Physics Vol. 39 No. 6 (1968) pp. 1605-1606 Symmetry Breaking in the SU(3) Chiral Dynamics Toshiyuki Minamikawa Progress of Theoretical Physics Vol. 40 No. 1 (1968) pp. 183-185 Low Energy Theorems for the Compton Scattering of the Isovector Photon from Spin 0 Systems in Chiral Dynamics Masataka Hosoda and Kazuhiko Ozaki Progress of Theoretical Physics Vol. 40 No. 6 (1968) pp. 1398-1401 Symmetry Breaking of Chiral SU(3) ⊗SU(3) and K-N Scattering Lengths Ken Kawarabayashi and Shinsaku Kitakado Progress of Theoretical Physics Vol. 40 No. 6 (1968) pp. 1402-1413 Nonleptonic Decays of K Mesons in Chiral Dynamics and the Proof of the ΔI=1/2 Rule Toshiyuki Minamikawa Progress of Theoretical Physics Vol. 42 No. 6 (1969) pp. 1372-1393 Chiral Symmetry with the ρ-Photon Analogy Tadayuki Ohta and Takeshi Ebata Progress of Theoretical Physics Vol. 45 No. 1 (1971) pp. 166-185 A Model for Weak Interactions Okiyasu Shito

Pion Prodution in Nucleon-Nucleon Collisions in Bev Range

Progress of Theoretical Physics Vol. 25 No. 6 (1961) pp. 1017-1027 Dispersion Relations for Virtual Pion-Nucleon Scattering J. Iizuka and A. Klein Progress of Theoretical Physics Vol. 28 No. 6 (1962) pp. 991-1025 One Boson Exchange Model in Proton-Proton Scattering Shoji Sawada, Tamotsu Ueda, Wataro Watari and Minoru Yonezawa Progress of Theoretical Physics Vol. 29 No. 6 (1963) pp. 829-850 The One Boson Exchange Model in the Single Pion Production Process in Proton-Proton Collision Tamotsu Ueda

High Energy<i>N</i><i>N</i>Scattering with Large Momentum Transfer and Chiral<i>S</i><i>U</i>(2)×<i>S</i><i>U</i>(2) Symmetry

Progress of Theoretical Physics Vol. 50 No. 6 (1973) pp. 1908-1915 Resolution of the Rapid Energy Dependence of pp-Polarization Minoru Biyajima Progress of Theoretical Physics Vol. 52 No. 1 (1974) pp. 249-258 Composite Model and High-Energy Behaviour of the Hadronic Process Kazuo Koike

Photo-Neutral Vector Meson Couplings in the Relativistic Extended Quark Model

Progress of Theoretical Physics Vol. 49 No. 1 (1973) pp. 282-292 High Energy Photo-Reactions and Generalized Vector Meson Dominance Model in the Relativistically Extended Quark Model Tsunehiro Kobayashi Progress of Theoretical Physics Vol. 52 No. 4 (1974) pp. 1355-1368 Gauge Freedom in Dual Feynman-Like Rules and Its Relation to the Massless Yang-Mills Field Theory Tamiaki Yoneya

On the Effects of Heavy Unstable Particles to the Anomalous Magnetic Moments of Nucleons

Progress of Theoretical Physics Vol. 18 No. 4 (1957) pp. 375–382 Anomalous Magnetic Moments of Hyperons and Mirror Theorem Hiroshi Katsumori Progress of Theoretical Physics Vol. 20 No. 2 (1958) pp. 149–162 Electromagnetic Properties of Nucleons Akira Kanazawa, Shinya Furui and Tetsuro Sakuma Progress of Theoretical Physics Vol. 22 No. 1 (1959) pp. 62–72 Strong Fermi-Type Interaction and Its Application to the GA/GV Ratio in β-Decay and the Anomalous Magnetic Moment of Nucleon Chikashi Iso Progress of Theoretical Physics Vol. 23 No. 6 (1960) pp. 1035–1054 Pion-Nulceon Interaction, Anomalous Magnetic Moment of Nucleon and Composite Model for Pion Chiaki Ihara Progress of Theoretical Physics Vol. 25 No. 6 (1961) pp. 1006–1016 Interactions in Nucleon Core Shigeo Minami

Two topics in the physics of light nuclei