Search results for "Jet"
showing 10 items of 4711 documents
Probing nuclear PDFs with dijets in ultra-peripheral Pb+Pb collisions
2019
In this talk we apply the photoproduction framework recently implemented into the Pythia 8 Monte Carlo event generator to study the potential of photo-nuclear dijets in ultra-peripheral Pb+Pb collisions at the LHC to further constrain the nuclear PDFs. These events can be described as $\gamma$A collisions where the relevant part of the flux of quasi-real photons from heavy-ions is obtained by using the equivalent photon approximation and cutting out impact-parameter values which would lead to hadronic interactions between the beam particles. In particular, we quantify the small-$x$ reach with different jet kinematics and show how well the values of $x$ derived from reconstructed jet momenta…
Hydrodynamical and Emission Simulations of Relativistic Jets: Stability and Generation of Superluminal and Stationary Components
2001
We present 2D hydrodynamical and emission simulations of the jet stabilityafter the introduction of strong perturbations on a relativistic jet. These simulations show that the interaction of a single strong perturbation with the underlying jet results in the formation of multiple conical shocks with very specific observational properties.
Interstellar travel guide: Chronicles of a violent universe
2016
In contrast to observations from our local viewpoint, the universe is extremely violent. Explosions of massive stars, X-ray and gamma-ray binary stars, and active galaxies are related to the presence of compact objects such as neutron stars or black holes. Processes such as matter accretion or the formation and release of relativistic plasma jets are responsible for the generation of large amounts of high-energy radiation, caused by the acceleration of elementary particles, and have a significant impact in their surroundings. Moreover, they are related to the generation of gravitational waves: vibrations in spacetime produced by the acceleration of compact massive objects that produce stron…
Statistical quantities in particle collisions
1972
Abstract Statistical quantities for particle collisions are defined using the analogy between the phase-space integral in multiparticle collisions and that in relativistic quantum statistical mechanics. The analogs of thermodynamic quantities are computed for the uncorrelated jet model. A relativistic derivation for the mass spectrum of hadrons is given and thermodynamic quantities are calculated for a system with this spectrum.
Four-jet final state production in $e^+ e^-$ collisions at centre-of-mass energies ranging from 130 to 184 GeV
1998
The four jet topology is analysed in the ALEPH data taken between November 1995 and November 1997, at centre-of-mass energies ranging from 130 to 184 GeV. While an unexpected accumulation of events with a dijet mas sum around 105 GeV/c**2 had been observed during the first run in 1995 at 130/136 GeV, corresponding to an integrated luminosity of 5.7 pb-1, no significant differences between data and standard model prediction is noticed, either in the high energy runs (81.1 pb-1 taken at centre-of-mass energies from 161 to 184 GeV) or in the 7.1 pb-1 recorded during a new short run at 130/136 GeV in 1997. We have found no other explanation for the earlier reported ``four jet anomaly'' than a s…
Measurement of the branching fraction for D0 → K-π+
1997
The branching fraction for D-0 --> K(-)pi(+) is measured with the statistics collected by ALEPH from 1991 to 1994. The method is based on the comparison between the rate for the reconstructed D*+ --> (D) pi(+), D-0 --> K(-)pi(+) decay chain and the rate for inclusive soft pion production at low transverse momentum with respect to the nearest jet. The result is B(D-0 --> K(-)pi(+)) = (3.90 +/- 0.09 +/- 0.12)% (C) 1997 Published by Elsevier Science B.V. RI ANTONELLI, ANTONELLA/C-6238-2011; Passalacqua, Luca/F-5127-2011; Murtas, Fabrizio/B-5729-2012; St.Denis, Richard/C-8997-2012; Sanchez, Federico/F-5809-2012; Forti, Francesco/H-3035-2011; Ferrante, Isidoro/F-1017-2012
Letter
2021
We present a study of the power threshold for L–H transitions (PLH) in almost pure helium plasmas, obtained in recent experiments at JET with an ITER-like wall (Be wall and W divertor). The most notable new result is that the density at which PLH is minimum, ${\bar{n}}_{\text{e},\mathrm{min}}$, is considerably higher for helium than for deuterium and hydrogen plasmas. We discuss the possible implications for ITER in its pre-fusion operating power phase.
A measurement of the ratio of the W and Z cross sections with exactly one associated jet in pp collisions at with ATLAS
2012
The ratio of production cross sections of the W and Z bosons with exactly one associated jet is presented as a function of jet transverse momentum threshold. The measurement has been designed to ma ...
Event shapes and jet rates in electron-positron annihilation at NNLO
2009
This article gives the perturbative NNLO results for the most commonly used event shape variables associated to three-jet events in electron-positron annihilation: Thrust, heavy jet mass, wide jet broadening, total jet broadening, C parameter and the Durham three-to-two jet transition variable. In addition the NNLO results for the jet rates corresponding to the Durham, Geneva, Jade-E0 and Cambridge jet algorithms are presented.
Measurement of the differential cross section of photon plus jet production inpp¯collisions ats=1.96 TeV
2013
We study the process of associated photon and jet production, p (p) over bar -> gamma + jet + X, using 8.7 fb(-1) of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy root s = 1.96 TeV. Photons are reconstructed with rapidity vertical bar y(gamma)vertical bar 20 GeV. The highest-p(T) jet is required to be in one of four rapidity regions up to vertical bar y(jet)vertical bar 0) and opposite signs (y(gamma)y(jet) <= 0) of photon and jet rapidities. We compare the measured triple-differential cross sections, d(3)sigma/dp(T)(gamma)dy(gamma)dy(jet), to next-to-leading order (NLO) perturbative QCD calculations using different sets of p…