J/ψ-PRODUCTION MECHANISMS AND DETERMINATION OF THE GLUON DENSITY AT HERA

1992 ◽  
Vol 07 (32) ◽  
pp. 7955-7988 ◽  
Author(s):  
H. JUNG ◽  
G.A. SCHULER ◽  
J. TERRON
Keyword(s):  
Gluon Fusion ◽  
Gluon Density ◽  
Color Singlet ◽  
Fixed Target ◽  
Fixed Target Experiments ◽  
Diffractive Production ◽  
Production Mechanisms ◽  
Inelastic Processes

We discuss photo- and leptoproduction of J/ψ mesons at energies ranging from those of fixed-target experiments up to those of HERA. Elastic and diffractive production as well as various inelastic processes are studied. We investigate the range in which J/ψ production is described by photon-gluon fusion in the color-singlet model. We show how inelastic J/ψ production at HERA can be used to extract the gluon density. We estimate an accessible range of 3×10−4<x<0.1 and discuss sources of errors in the reconstruction of the gluon density at HERA.

scholarly journals Quarkonium Production at Z0 and in ϒ(1S) Decay

1997 ◽  
Vol 12 (22) ◽  
pp. 3931-3940
Author(s):  
Kingman Cheung ◽  
Wai-Yee Keung ◽  
Tzu Chiang Yuan
Keyword(s):  
Color Singlet ◽  
Fixed Target ◽  
Production Rates ◽  
Fixed Target Experiments ◽  
Color Octet ◽  
Quarkonium Production ◽  
Color Octet Mechanism

The conventional color-singlet model was challenged by the recent data on quarkonium production. Discrepancies in production rates were observed at the Tevatron, at LEP, and in fixed-target experiments. The newly advocated color-octet mechanism provides a plausible solution to the anomalous quarkonium production observed at the Tevatron. The color-octet mechanism should also affect other quarkonium production channels. In this paper we will summarize the studies of quarkonium production in Z0 and ϒ decays.

scholarly journals Fixed target experiments at the Fermilab Tevatron

2014 ◽  
Vol 29 (28) ◽  
pp. 1446008 ◽  
Author(s):  
Gaston Gutierrez ◽  
Marco A. Reyes
Keyword(s):  
Center Of Mass ◽  
Partial Wave Analysis ◽  
Fixed Target ◽  
Liquid Hydrogen Target ◽  
Hydrogen Target ◽  
Fixed Target Experiments ◽  
Center Of Mass Energy ◽  
Diffractive Production ◽  
Target Program ◽  
Central Production

This paper presents a review of the study of Exclusive Central Production at a center-of-mass energy of [Formula: see text] at the Fermilab Fixed Target program. In all reactions reviewed in this paper, protons with an energy of 800 GeV were extracted from the Tevatron accelerator at Fermilab and directed to a Liquid Hydrogen target. The states reviewed include [Formula: see text], ϕϕ and D*±. Partial Wave Analysis results will be presented on the light states but only the cross-section will be reviewed in the diffractive production of D*±.

scholarly journals Collinear expansion for color singlet cross sections

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Markus A. Ebert ◽  
Bernhard Mistlberger ◽  
Gherardo Vita
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Production Cross ◽  
Gluon Fusion ◽  
Building Blocks ◽  
Color Singlet ◽  
Final State ◽  
Beam Function ◽  
Kinematic Limit ◽  
State Radiation

Abstract We demonstrate how to efficiently expand cross sections for color-singlet production at hadron colliders around the kinematic limit of all final state radiation being collinear to one of the incoming hadrons. This expansion is systematically improvable and applicable to a large class of physical observables. We demonstrate the viability of this technique by obtaining the first two terms in the collinear expansion of the rapidity distribution of the gluon fusion Higgs boson production cross section at next-to-next-to leading order (NNLO) in QCD perturbation theory. Furthermore, we illustrate how this technique is used to extract universal building blocks of scattering cross section like the N-jettiness and transverse momentum beam function at NNLO.

scholarly journals Measurement of meson cross sections at HERA and determination of the gluon density in the proton using NLO QCD

1999 ◽  
Vol 545 (1-3) ◽  
pp. 21-44 ◽  
Author(s):  
C. Adloff ◽  
M. Anderson ◽  
V. Andreev ◽  
B. Andrieu ◽  
V. Arkadov ◽  
...  
Keyword(s):  
Cross Sections ◽  
Gluon Density

scholarly journals Review of accelerator-based searches for Neutral Long-Lived Particles

2019 ◽  
Vol 43 (169) ◽  
pp. 638-645
Author(s):  
Marta Losada
Keyword(s):  
Parameter Space ◽  
Coupling Strength ◽  
Current Status ◽  
Next Generation ◽  
Fixed Target ◽  
Beam Dump ◽  
Basic Formalism ◽  
Neutral Lepton

In this paper we present the current status of searches for neutral long-lived particles. The basic formalism that allows the determination of the number of expected long-lived particles is presented. Heavy neutral leptons can be a type of long-lived particles. The main observational motivations for the existence of heavy neutral lepton is covered as well. A summary of the main results from both collider searches and fixed target/beam dump experiments is presented. The outlook for next generation experiments and their impact on the parameter space of coupling strength and mass of heavy neutral leptons is also discussed.

scholarly journals Interactions of Beams with Surroundings

2020 ◽  
pp. 183-203
Author(s):  
M. Brugger ◽  
H. Burkhardt ◽  
B. Goddard ◽  
F. Cerutti ◽  
R. G. Alia
Keyword(s):  
High Energy Physics ◽  
High Energy ◽  
Fixed Target ◽  
Fixed Target Experiments ◽  
Secondary Particles ◽  
Radiation Sources ◽  
Residual Gas ◽  
The Impact ◽  
High Energy Particles ◽  
Energy Physics

AbstractWith the exceptions of Synchrotron Radiation sources, beams of accelerated particles are generally designed to interact either with one another (in the case of colliders) or with a specific target (for the operation of Fixed Target experiments, the production of secondary beams and for medical applications). However, in addition to the desired interactions there are unwanted interactions of the high energy particles which can produce undesirable side effects. These interactions can arise from the unavoidable presence of residual gas in the accelerator vacuum chamber, or from the impact of particles lost from the beam on aperture limits around the accelerator, as well as the final beam dump. The wanted collisions of the beams in a collider to produce potentially interesting High Energy Physics events also reduces the density of the circulating beam and can produce high fluxes of secondary particles.

scholarly journals Effects of azimuth-symmetric acceptance cutoffs on the measured asymmetry in unpolarized Drell-Yan fixed-target experiments

2013 ◽  
Vol 49 (4) ◽  
Author(s):  
A. Bianconi ◽  
M. P. Bussa ◽  
M. Destefanis ◽  
L. Ferrero ◽  
M. Greco ◽  
...  
Keyword(s):  
Fixed Target ◽  
Fixed Target Experiments ◽  
Measured Asymmetry
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