scholarly journals Mining for Gluon Saturation at Colliders

Universe ◽  
2021 ◽  
Vol 7 (8) ◽  
pp. 312 ◽  
Author(s):  
Astrid Morreale ◽  
Farid Salazar
Keyword(s):  
Particle Physics ◽  
High Energy ◽  
Strong Interactions ◽  
Asymptotic Freedom ◽  
High Energies ◽  
The Past ◽  
Color Confinement ◽  
Small X ◽  
Gluon Saturation ◽  
Physics Experiments

Quantum chromodynamics (QCD) is the theory of strong interactions of quarks and gluons collectively called partons, the basic constituents of all nuclear matter. Its non-abelian character manifests in nature in the form of two remarkable properties: color confinement and asymptotic freedom. At high energies, perturbation theory can result in the growth and dominance of very gluon densities at small-x. If left uncontrolled, this growth can result in gluons eternally growing violating a number of mathematical bounds. The resolution to this problem lies by balancing gluon emissions by recombinating gluons at high energies: phenomena of gluon saturation. High energy nuclear and particle physics experiments have spent the past decades quantifying the structure of protons and nuclei in terms of their fundamental constituents confirming predicted extraordinary behavior of matter at extreme density and pressure conditions. In the process they have also measured seemingly unexpected phenomena. We will give a state of the art review of the underlying theoretical and experimental tools and measurements pertinent to gluon saturation physics. We will argue for the need of high energy electron-proton/ion colliders such as the proposed EIC (USA) and LHeC (Europe) to consolidate our knowledge of QCD knowledge in the small x kinematic domains.

scholarly journals GLUON SATURATION AND THE FROISSART BOUND: A SIMPLE APPROACH

2008 ◽  
Vol 23 (33) ◽  
pp. 2847-2857 ◽  
Author(s):  
F. CARVALHO ◽  
F. O. DURÃES ◽  
V. P. GONÇALVES ◽  
F. S. NAVARRA
Keyword(s):  
Cross Sections ◽  
High Energy ◽  
Simple Approach ◽  
Strong Interactions ◽  
Color Glass ◽  
Momentum Scale ◽  
Total Cross Sections ◽  
High Energies ◽  
Gluon Saturation ◽  
Very High

At very high energies we expect that the hadronic cross sections satisfy the Froissart bound, which is a well-established property of the strong interactions. In this energy regime we also expect the formation of the Color Glass Condensate, characterized by gluon saturation and a typical momentum scale: the saturation scale Qs. In this paper we show that if a saturation window exists between the nonperturbative and perturbative regimes of Quantum Chromodynamics (QCD), the total cross sections satisfy the Froissart bound. Furthermore, we show that our approach allows us to describe the high energy experimental data on [Formula: see text] total cross sections.

scholarly journals Team and project composition in big physics experiments

2019 ◽  
Vol 30 (4) ◽  
pp. 535-542
Author(s):  
Slobodan Perovic
Keyword(s):  
Particle Physics ◽  
High Energy Physics ◽  
Physical World ◽  
High Energy ◽  
Data Driven ◽  
Physical Constraints ◽  
High Energies ◽  
Physics Experiments ◽  
Case Based ◽  
Energy Physics

Identifying optimal ways of organizing exploration in particle physics mega-labs is a challenging task that requires a combination of case-based and formal epistemic approaches. Data-driven studies suggest that projects pursued by smaller master-teams (fewer members, fewer sub-teams) are substantially more efficient than larger ones across sciences, including experimental particle physics. Smaller teams also seem to make better project choices than larger, centralized teams. Yet the epistemic requirement of small, decentralized, and diverse teams contradicts the often emphasized and allegedly inescapable logic of discovery that forces physicists pursuing the fundamental levels of the physical world to perform centralized experiments in mega-labs at high energies. We explain, however, that this epistemic requirement could be met, since the nature of theoretical and physical constraints in high energy physics and the technological obstacles stemming from them turn out to be surprisingly open-ended.

scholarly journals Dark matter, dark energy and gravity

2015 ◽  
Vol 24 (02) ◽  
pp. 1550012 ◽  
Author(s):  
B. A. Robson
Keyword(s):  
Dark Matter ◽  
Dark Energy ◽  
Particle Physics ◽  
Composite Structures ◽  
Gravitational Interaction ◽  
Asymptotic Freedom ◽  
Generation Model ◽  
Newtonian Gravitation ◽  
Color Confinement ◽  
Vector Bosons

Within the framework of the Generation Model (GM) of particle physics, gravity is identified with the very weak, universal and attractive residual color interactions acting between the colorless particles of ordinary matter (electrons, neutrons and protons), which are composite structures. This gravitational interaction is mediated by massless vector bosons (hypergluons), which self-interact so that the interaction has two additional features not present in Newtonian gravitation: (i) asymptotic freedom and (ii) color confinement. These two additional properties of the gravitational interaction negate the need for the notions of both dark matter and dark energy.

scholarly journals Programmable combinational logic trigger system for high energy particle physics experiments

1977 ◽  
Vol 140 (3) ◽  
pp. 549-552 ◽  
Author(s):  
E.D. Platner ◽  
A. Etkin ◽  
K.J. Foley ◽  
J.H. Goldman ◽  
W.A. Love ◽  
...  
Keyword(s):  
Particle Physics ◽  
High Energy ◽  
High Energy Particle ◽  
Combinational Logic ◽  
Trigger System ◽  
Energy Particle ◽  
Physics Experiments

scholarly journals QUARK MATTER AND NUCLEAR COLLISIONS A BRIEF HISTORY OF STRONG INTERACTION THERMODYNAMICS

2012 ◽  
Vol 21 (08) ◽  
pp. 1230006 ◽  
Author(s):  
HELMUT SATZ
Keyword(s):  
High Energy ◽  
Big Bang ◽  
Nuclear Collision ◽  
Strong Interactions ◽  
Extreme Temperatures ◽  
Nuclear Collisions ◽  
The Past ◽  
History Of ◽  
The Big Bang ◽  
Theory And Experiment

The past 50 years have seen the emergence of a new field of research in physics, the study of matter at extreme temperatures and densities. The theory of strong interactions, quantum chromodynamics (QCD), predicts that in this limit, matter will become a plasma of deconfined quarks and gluons — the medium which made up the early universe in the first 10 microseconds after the Big Bang. High energy nuclear collisions are expected to produce short-lived bubbles of such a medium in the laboratory. I survey the merger of statistical QCD and nuclear collision studies for the analysis of strongly interacting matter in theory and experiment.

scholarly journals What is duality?

1970 ◽  
Vol 318 (1534) ◽  
pp. 257-278 ◽  
Keyword(s):  
Sum Rules ◽  
Scattering Amplitude ◽  
Finite Energy ◽  
High Energy ◽  
Low Energy ◽  
Strong Interactions ◽  
High Energies ◽  
Resonance Formation ◽  
Interference Models ◽  
Regge Poles

Duality gives a satisfying connexion between two different areas of strong interaction physics, Regge poles at high energy and resonances at low energy. This interlocking gives powerful bootstrap conditions, and together with the assumption that certain channels do not contain resonances it gives strong restrictions on the hadron spectrum. Since there is some confusion about the term duality, we shall explain what is meant by the various forms of duality (f. e. s. r. (finite energy sum rules) duality, local duality), and what is meant by ‘building up’, and we shall show in what way antidual models (such as the generalized interference model) come into conflict with basic empirical facts. Duality expresses the relation between two descriptions of the hadronic scattering amplitude. At low energy (l. e.) the description by direct-channel resonances is simple and useful (see figure 1). At low energy the data show prominent peaks as a function of energy, and one may try the approximation of resonance saturation, i. e. of neglecting the non-resonating background. The second description is the exchange of Regge poles, and it is useful at high energies (h.e.), where typical features are forward peaks, energy dependence s α , and structure at fixed t (see figure 2). The two descriptions are very different; resonance formation corresponds to poles in the s channel, Regge exchange to poles in the t channel. Duality says that there are direct relations between these two descriptions, that they are equivalent in a certain sense. In complete contrast, the interference models postulate that one must add the two descriptions. (If lowest order perturbation theory was relevant to strong interactions, one would be led to adding the diagrams.)

scholarly journals Muon to electron conversion: how to find an electron in a muon haystack

2010 ◽  
Vol 368 (1924) ◽  
pp. 3645-3655 ◽  
Author(s):  
A. Kurup
Keyword(s):  
Particle Physics ◽  
Energy Production ◽  
Electron Transition ◽  
Neutrino Factory ◽  
The Past ◽  
The Standard Model ◽  
Electron Conversion ◽  
History Of ◽  
Physics Experiments ◽  
The Universe

The standard model (SM) of particle physics describes how the Universe works at a fundamental level. Even though this theory has proven to be very successful over the past 50 years, we know it is incomplete. Many theories that go beyond the SM predict the occurrence of certain processes that are forbidden by the SM, such as muon to electron conversion. This paper will briefly review the history of muon to electron conversion and focus on the high-precision experiments currently being proposed, COMET (Coherent Muon to Electron Transition) and Mu2e, and a next-generation experiment, PRISM. The PRISM experiment intends to use a novel type of accelerator called a fixed-field alternating-gradient (FFAG) accelerator. There has recently been renewed interest in FFAGs for the Neutrino Factory and the Muon Collider, and because they have applications in many areas outside of particle physics, such as energy production and cancer therapy. The synergies between these particle physics experiments and other applications will also be discussed.

scholarly journals SMALL-X QCD EFFECTS IN PARTICLE COLLISIONS AT HIGH ENERGIES

2002 ◽  
Vol 17 (23) ◽  
pp. 3185-3203
Author(s):  
TANCREDI CARLI
Keyword(s):  
Perturbative Qcd ◽  
Cross Sections ◽  
High Energy ◽  
Particle Collisions ◽  
Energy Limit ◽  
High Energy Limit ◽  
High Energies ◽  
Small X ◽  
Theoretical Developments

Recent theoretical developments to calculate cross sections of hadronic objects in the high energy limit are summarised and experimental attempts to establish the need for new QCD effects connected with a resummation of small hadron momentum fractions x are reviewed. The relation between small-x parton dynamics and the phenomenon of diffraction is briefly out-lined. In addition, a search for a novel, non-perturbative QCD effect, the production of QCD instanton induced events, is presented.

Particle physics II

Quantum 20/20 ◽  
2019 ◽  
pp. 351-372
Author(s):  
Ian R. Kenyon
Keyword(s):  
Symmetry Group ◽  
Particle Physics ◽  
Massive Particle ◽  
Scalar Fields ◽  
High Energy ◽  
Strong Interactions ◽  
Proton Proton ◽  
Proton Structure ◽  
Quantum Gauge Theory ◽  
Vector Bosons

Quantum chromodynamics the quantum gauge theory of strong interactions is presented: SU(3) being the (colour) symmetry group. The colour content of strongly interacting particles is described. Gluons, the field particles, carry colour so that they mutually interact – unlike photons. Renormalization leads to the coupling strength declining at large four momentum transfer squared q 2 and to binding of quarks in hadrons at small q 2. The cutoff in the range of the strong interaction is shown to be due to this low q 2 behaviour, despite the gluon being massless. In high energy interactions, say proton-proton collisions, the initial process is a hard (high q 2) parton+parton to parton+parton process. After which the partons undergo softer interactions leading finally to emergent hardrons. Experiments at DESY probing proton structure with electrons are described. An account of electroweak unification completes the book. The weak interaction symmetry group is SUL(2), L specifying handedness. This makes the electroweak symmetry U(1)⊗SUL(2). The weak force carriers, W± and Z0, are massive, which is at odds with the massless carriers required by quantum gauge theories. How the BEH mechanism resolves this problem is described. It involves spontaneous symmetry breaking of the vacuum with scalar fields. The outcome are massive gauge field particles to match the W± and Z0 trio, a massless photon, and a scalar field with a massive particle, the Higgs boson. The experimental programmes that discovered the vector bosons in 1983 and the Higgs in 2012 are described, including features of generic detectors. Finally puzzles revealed by our current understanding are outlined.

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