Search results for "Correlation"
showing 10 items of 2282 documents
Multiplicity dependence of jet-like two-particle correlation structures in p–Pb collisions at sNN=5.02 TeV
2015
Two-particle angular correlations between unidentified charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV. The transverse-momentum range 0.7<pT,assoc<pT,trig<5.0 GeV/c is examined, to include correlations induced by jets originating from low momentum-transfer scatterings (minijets). The correlations expressed as associated yield per trigger particle are obtained in the pseudorapidity range |η|<0.9. The near-side long-range pseudorapidity correlations observed in high-multiplicity p-Pb collisions are subtracted from both near-side short-range and away-side correlations in order to remove the no…
Two-pion Bose-Einstein correlations inppcollisions ats=900 GeV
2010
We report on the measurement of two-pion correlation functions from pp collisions at root s = 900 GeV performed by the ALICE experiment at the Large Hadron Collider. Our analysis shows an increase of the Hanbury Brown-Twiss radius with increasing event multiplicity, in line with other measurements done in particle- and nuclear collisions. Conversely, the strong decrease of the radius with increasing transverse momentum, as observed at the Relativistic Heavy Ion Collider and at Tevatron, is not manifest in our data.
Prospects of searching for (un)particles from Hidden Sectors using rapidity correlations in multiparticle production at the LHC
2008
Most signatures of new physics have been studied on the transverse plane with respect to the beam direction at the LHC where background is much reduced. In this paper we propose the analysis of inclusive longitudinal (pseudo) rapidity correlations among final-state (charged) particles in order to search for (un)particles belonging to a hidden sector beyond the Standard Model, using a selected sample of p-p minimum bias events (applying appropriate off-line cuts on events based on, e.g. minijets, high-multiplicity, event shape variables, high-p(perpendicular to) leptons and photons, etc.) collected at the early running of the LHC. To this aim, we examine inclusive and semi-inclusive two-part…
Femtoscopy ofppcollisions ats=0.9and 7 TeV at the LHC with two-pion Bose-Einstein correlations
2011
We report on the high statistics two-pion correlation functions from pp collisions at root s = 0.9 TeV and root s = 7 TeV, measured by the ALICE experiment at the Large Hadron Collider. The correlation functions as well as the extracted source radii scale with event multiplicity and pair momentum. When analyzed in the same multiplicity and pair transverse momentum range, the correlation is similar at the two collision energies. A three-dimensional femtoscopic analysis shows an increase of the emission zone with increasing event multiplicity as well as decreasing homogeneity lengths with increasing transverse momentum. The latter trend gets more pronounced as multiplicity increases. This sug…
Search for new physics inlepton+photon+Xevents with929 pb−1ofpp¯collisions ats=1.96 TeV
2007
The authors present results of a search for anomalous production of events containing a charged lepton ({ell}, either e or {mu}) and a photon ({gamma}), both with high transverse momentum, accompanied by additional signatures, X, including missing transverse energy (E{sub T}) and additional leptons and photons. We use the same kinematic selection criteria as in a previous CDF search, but with a substantially larger data set, 305 pb{sup -1}, a p{bar p} collision energy of 1.96 TeV, and the upgraded CDF II detector. We find 42 {ell}{gamma}E{sub T} events versus a standard model expectation of 37.3 {+-} 5.4 events. The level of excess observed in Run I, 16 events with an expectation of 7.6 {+-…
The Proton Spectrum in Neutron Beta Decay: Latest Results with the aSPECT Spectrometer
2009
Abstract The purpose of the neutron decay spectrometer aSPECT is to determine the antineutrino electron angular correlation coefficient a with high precision. Latest measurements with aSPECT were performed during April/May 2008 at the Institut Laue-Langevin in Grenoble, France. In this paper we give a report on the experiment and the status of the ongoing data analysis.
The EM imaging reconstruction method in γ-ray astronomy
1998
Abstract The simpler imaging reconstruction methods used for γ-ray coded mask telescopes are based on correlation methods, very fast and simple-to-use but with limitations in the reconstructed image. To improve these results, other reconstruction methods have been developed, such as the maximum entropy methods or the Iterative Removal Of Sources (IROS). However, such kind of methods are slower and can be impracticable for very complex telescopes. In this paper we present an alternative image reconstruction method, based on an iterative maximum likelihood algorithm called the EM algorithm, easy to implement and that can be successfully used for not very complex coded mask systems, as is the …
On the variational approach to Jastrow correlations in nuclei
1973
The variational equation determining the Jastrow correlation function is investigated with particular emphasis on the healing problem for both nuclear matter and finite nuclei. The consequences of several healing conditions are discussed. Furthermore, influences from the choice of the single particle basis and from long range correlations are studied and are found to be small in the short range region.
Beta-decay studies of far from stability nuclei near N = 28
1995
Abstract Beta-decay half-lives and β-delayed neutron-emission probabilities of the very neutron-rich nuclei 43 P, 42,44,45 S and 44–46 Cl, 47 Ar, which lie at or close to the N=28 magic shell, have been recently measured through β or β-n time correlation measurement. The results are compared to recent model predictions and indicate a rapid weakening of the N=28 shell effect below 48 Ca. The nuclear structure effects reflected in the decay properties of the exotic S and Cl isotopes may be the clue for the astrophysical understanding of the unusual 48 Ca 46 Ca abundance ratio measured in the solar system.
Analysis of transverse momentum correlations in hadronic Z decays
1999
In a recent paper, evidence was presented for a significant, positive correlation between the total transverse momenta of particles on opposite hemispheres of hadronic events. A new, model independent analysis of the data has been made. Two components can be distinguished in the correlation, and quantitative estimates of each are given. The results form a significant test of Monte Carlo models and some of the physics behind them. (C) 1999 Published by Elsevier Science B.V. All rights reserved.