Results from the data obtained in the first physics run of the Relativistic Heavy Ion Collider (RHIC) have shown surprisingly large elliptic flow and suprisingly small HBT radii. Attempts to explain ...both results in a consistant picture have so far been unsuccessful. The present work shows that a simple thermal-like initial state model coupled to a hadronic rescattering calculation can explain reasonably well both elliptic flow and HBT results from RHIC. The calculation suggests a very early hadronization time of about 1 fm/c after the initial collision of the nuclei.
Probe station for testing of ALICE silicon drift detectors Humanic, T.J; Kotov, I.V; Piemonte, C ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2003, Letnik:
512, Številka:
1
Journal Article
Recenzirano
Large area,
7.25
cm×8.76
cm
silicon drift detectors have been developed and are in production for the ALICE experiment at LHC. An active area of the detector of more than
50
cm
2
imposes high demands ...on the quality of processing and raw material. Automated testing procedures have been developed to test detectors before mounting them on the ladders. Probe stations for ALICE SDD testing were designed and built at INFN, Trieste and Ohio State University (OSU). Testing procedures, detector selection criteria and some details of the OSU probe station design are discussed.
A
bstract
The jet angularities are a class of jet substructure observables which characterize the angular and momentum distribution of particles within jets. These observables are sensitive to ...momentum scales ranging from perturbative hard scatterings to nonperturbative fragmentation into final-state hadrons. We report measurements of several groomed and ungroomed jet angularities in pp collisions at
s
= 5
.
02 TeV with the ALICE detector. Jets are reconstructed using charged particle tracks at midrapidity (
|η| <
0
.
9). The anti-
k
T
algorithm is used with jet resolution parameters
R
= 0
.
2 and
R
= 0
.
4 for several transverse momentum
p
T
ch
jet
intervals in the 20–100 GeV/
c
range. Using the jet grooming algorithm Soft Drop, the sensitivity to softer, wide-angle processes, as well as the underlying event, can be reduced in a way which is well-controlled in theoretical calculations. We report the ungroomed jet angularities,
λ
α
, and groomed jet angularities,
λ
α
,g
, to investigate the interplay between perturbative and nonperturbative effects at low jet momenta. Various angular exponent parameters
α
= 1, 1.5, 2, and 3 are used to systematically vary the sensitivity of the observable to collinear and soft radiation. Results are compared to analytical predictions at next-to-leading-logarithmic accuracy, which provide a generally good description of the data in the perturbative regime but exhibit discrepancies in the nonperturbative regime. Moreover, these measurements serve as a baseline for future ones in heavy-ion collisions by providing new insight into the interplay between perturbative and nonperturbative effects in the angular and momentum substructure of jets. They supply crucial guidance on the selection of jet resolution parameter, jet transverse momentum, and angular scaling variable for jet quenching studies.
PDF
