4,560 research outputs found
NA60 results on phi production in the hadronic and leptonic channels in In-In collisions at 158 GeV
The NA60 experiment at the CERN SPS studied phi meson production in In-In
collisions at 158 A GeV via muon and kaon decay channels. Results in the
hadronic channel are presented for the first time. These are discussed in the
framework of the so-called phi puzzle through the comparison with the previous
NA60 measurements in the muon channel. The yield and inverse m_T slopes
observed in the two channels are compatible within errors, showing that the
large discrepancies seen in Pb-Pb collisions between NA50 (muon pairs) and NA49
(kaon pairs) are not seen in the NA60 In-In data.Comment: 4 pages, 4 figures - To appear in the conference proceedings for
Quark Matter 2009, March 30 - April 4, Knoxville, Tennesse
Translationally controlled tumor protein in prostatic adenocarcinoma: correlation with tumor grading and treatment-related changes
12Prostate cancer is the second leading cause of cancer-related death. The androgen deprivation therapy is the standard treatment for advanced stages. Unfortunately, virtually all tumors become resistant to androgen withdrawal. The progression to castration-resistance is not fully understood, although a recent paper has suggested translationally controlled tumor protein to be implicated in the process. The present study was designed to investigate the role of this protein in prostate cancer, focusing on the correlation between its expression level with tumor differentiation and response to treatment. We retrieved 292 prostatic cancer specimens; of these 153 had been treated only by radical prostatectomy and 139 had undergone radical prostatectomy after neoadjuvant treatment with combined androgen blockade therapy. Non-neoplastic controls were represented by 102 prostatic peripheral zone specimens. In untreated patients, the expression of the protein, evaluated by RT-qPCR and immunohistochemistry, was significantly higher in tumor specimens than in non-neoplastic control, increasing as Gleason pattern and score progressed. In treated prostates, the staining was correlated with the response to treatment. An association between protein expression and the main clinicopathological factors involved in prostate cancer aggressiveness was identified. These findings suggest that the protein may be a promising prognostic factor and a target for therapy.openopenRocca, Bruno Jim; Ginori, Alessandro; Barone, Aurora; Calandra, Calogera; Crivelli, Filippo; De Falco, Giulia; Gazaneo, Sara; Tripodi, Sergio; Cevenini, Gabriele; Del Vecchio, Maria Teresa; Ambrosio, Maria Raffaella; Tosi, PieroRocca, BRUNO JIM; Ginori, Alessandro; Barone, Aurora; Calandra, Calogera; Crivelli, Filippo; DE FALCO, Giulia; Gazaneo, Sara; Tripodi, Sergio; Cevenini, Gabriele; DEL VECCHIO, MARIA TERESA; Ambrosio, MARIA RAFFAELLA; Tosi, Pier
Beauty physics with heavy ions and prospects
Heavy flavours are generally considered one of the fundamental probes of the Quark-Gluon Plasma (QGP), the state of matter in which partons are deconfined, that can be created in relativistic heavy-ion collisions. Due to their large mass, heavy quarks are predominantly produced in hard scattering processes during the early stages of the collision lie Open heavy flavour measurements may probe the energy density of the system by means of the energy loss through elastic scatterings and gluon radiation. The radiative energy loss is predicted by QCD to be larger for gluons than for quarks, and light quark energy loss should be larger than that for heavy quarks due to the dead cone effect. The measurement of the yield of beauty hadrons can therefore shed light on the energy loss mechanism and on the mass hierarchy. Quarkonia are another crucial probe of the QGP. They can melt in the medium due to color screening at a temperature which increases with the binding energy of the system, thus acting as a probe of the QGP temperature. Bottomonia are of particular interest in this respect, since they can provide a clear suppression pattern. Beauty and bottomonia measurements in heavy-ion collisions at the LHC are reviewed. Results based on semi-leptonic decays of charm and beauty hadrons, non-prompt J/y from B decays and b-tagged jets in Pb-Pb collisions are discussed, as well as the measurements of i suppression at mid and forward rapidity provided by the CMS and ALICE experiments. Cold nuclear matter effects are investigated through the measurements in p-Pb collisions
Geographic variation and environmental conditions as cofactors in Chlamydia psittaci association with ocular adnexal lymphomas: a comparison between Italian and African samples
A particular extra-nodal lymphoma type arises from B cells of the marginal zone (MZ) of mucosa-associated lymphoid tissue (MALT). The aetiology ofMZ lymphomas suggests that they are associated with chronic antigenic stimulation by microbial pathogens, among which Helicobacter pylori-associated gastricMALT lymphoma is the best studied. Recently, MALT lymphomas have been described in the context of chronic conjunctivitis, which can be associated with Chlamydia spp. infection. Studies from Italy showed the presence of Chlamydia psittaci in 87% of ocular adnexal lymphomas (OAL), and C. psittaci has been described in a large part of samples from Austria and Korea as well. However, this finding was not always confirmed by other studies, suggesting that the association with C. psittaci may depend on geographic heterogeneity. Interestingly, none of the studies up to now has been carried out in the African population, where a strong association between infectious agents and the occurrence of human neoplasms has been reported. This study was designed to investigate the possible association of Chlamydia psittaci in cases retrieved from Kenya, compared to cases from Italy. Our results showed that there was a marked variation between the two geographical areas in terms of association with C. psittaci, as 17% (5/30) of the samples from Italy were positive for C. psittaci, whereas no association with this pathogen was observed in any of the African samples (0/9), suggesting that other cofactors may determine the OAL occurrence in those areas. OAL cases are often characterized by down-regulation of p16/INK4a expression and promoter hypermethylation of the p16/ INK4a gene. Our results showed a partial methylation of p16/INK4a promoter in C. psittacinegative cases, whereas no hypermethylation of this gene was found in C. psittaci-positive cases, suggesting that mechanisms other than promoter hypermethylation lead to p16/ INK4a silencing in C. psittaci-positive cases. We may conclude that the role of epidemiologic, environmental and genetic factors, must be considered in the aetiology of this disease
J/psi azimuthal anisotropy relative to the reaction plane in Pb-Pb collisions at 158 GeV per nucleon
The J/ azimuthal distribution relative to the reaction plane has been
measured by the NA50 experiment in Pb-Pb collisions at 158 GeV/nucleon. Various
physical mechanisms related to charmonium dissociation in the medium created in
the heavy ion collision are expected to introduce an anisotropy in the
azimuthal distribution of the observed J/ mesons at SPS energies. Hence,
the measurement of J/ elliptic anisotropy, quantified by the Fourier
coefficient v of the J/ azimuthal distribution relative to the
reaction plane, is an important tool to constrain theoretical models aimed at
explaining the anomalous J/ suppression observed in Pb-Pb collisions. We
present the measured J/ yields in different bins of azimuthal angle
relative to the reaction plane, as well as the resulting values of the Fourier
coefficient v as a function of the collision centrality and of the
J/ transverse momentum. The reaction plane has been estimated from the
azimuthal distribution of the neutral transverse energy detected in an
electromagnetic calorimeter. The analysis has been performed on a data sample
of about 100 000 events, distributed in five centrality or p
sub-samples. The extracted v values are significantly larger than zero
for non-central collisions and are seen to increase with p.Comment: proceedings of HP08 conference corrected a typo in one equatio
Data-driven precision determination of the material budget in ALICE
The knowledge of the material budget with a high precision is fundamental for measurements of direct photon production using the photon conversion method due to its direct impact on the total systematic uncertainty. Moreover, it influences many aspects of the charged-particle reconstruction performance. In this article, two procedures to determine data-driven corrections to the material-budget description in ALICE simulation software are developed. One is based on the precise knowledge of the gas composition in the Time Projection Chamber. The other is based on the robustness of the ratio between the produced number of photons and charged particles, to a large extent due to the approximate isospin symmetry in the number of produced neutral and charged pions. Both methods are applied to ALICE data allowing for a reduction of the overall material budget systematic uncertainty from 4.5% down to 2.5%. Using these methods, a locally correct material budget is also achieved. The two proposed methods are generic and can be applied to any experiment in a similar fashion
Measurement of beauty-strange meson production in Pb-Pb collisions at √sNN=5.02 TeV via non-prompt Ds+ mesons
The production yields of non-prompt Ds+ mesons, namely Ds+ mesons from beauty-hadron decays, were measured for the first time as a function of the transverse momentum (pT) at midrapidity (|y|<0.5) in central and semi-central Pb–Pb collisions at a centre-of-mass energy per nucleon pair sNN=5.02TeV with the ALICE experiment at the LHC. The Ds+ mesons and their charge conjugates were reconstructed from the hadronic decay channel Ds+→φπ+, with φ→K−K+, in the 4<36GeV/c and 2<24GeV/c intervals for the 0–10% and 30–50% centrality classes, respectively. The measured yields of non-prompt Ds+ mesons are compared to those of prompt Ds+ and non-prompt D0 mesons by calculating the ratios of the production yields in Pb–Pb collisions and the nuclear modification factor RAA. The ratio between the RAA of non-prompt Ds+ and prompt Ds+ mesons, and that between the RAA of non-prompt Ds+ and non-prompt D0 mesons in central Pb–Pb collisions are found to be on average higher than unity in the 4<12GeV/c interval with a statistical significance of about 1.6σ and 1.7σ, respectively. The measured RAA ratios are compared with the predictions of theoretical models of heavy-quark transport in a hydrodynamically expanding QGP that incorporate hadronisation via quark recombination
Probing the chiral magnetic wave with charge-dependent fow measurements in Pb-Pb collisions at the LHC
The Chiral Magnetic Wave (CMW) phenomenon is essential to provide insights into the strong interaction in QCD, the properties of the quark-gluon plasma, and the topological characteristics of the early universe, offering a deeper understanding of fundamental physics in high-energy collisions. Measurements of the charge-dependent anisotropic flow coefficients are studied in Pb-Pb collisions at center-of-mass energy per nucleon-nucleon collision sNN = 5.02 TeV to probe the CMW. In particular, the slope of the normalized difference in elliptic (v2) and triangular (v3) flow coefficients of positively and negatively charged particles as a function of their event-wise normalized number difference, is reported for inclusive and identified particles. The slope r3Norm is found to be larger than zero and to have a magnitude similar to r2Norm, thus pointing to a large background contribution for these measurements. Furthermore, r2Norm can be described by a blast wave model calculation that incorporates local charge conservation. In addition, using the event shape engineering technique yields a fraction of CMW (fCMW) contribution to this measurement which is compatible with zero. This measurement provides the very first upper limit for fCMW, and in the 10–60% centrality interval it is found to be 26% (38%) at 95% (99.7%) confidence level
Closing in on critical net-baryon fluctuations at LHC energies: Cumulants up to third order in Pb-Pb collisions
Fluctuation measurements are important sources of information on the mechanism of particle production at LHC energies. This article reports the first experimental results on third-order cumulants of the net-proton distributions in Pb–Pb collisions at a center-of-mass energy sNN=5.02 TeV recorded by the ALICE detector. The results on the second-order cumulants of net-proton distributions at sNN=2.76 and 5.02 TeV are also discussed in view of effects due to the global and local baryon number conservation. The results demonstrate the presence of long-range rapidity correlations between protons and antiprotons. Such correlations originate from the early phase of the collision. The experimental results are compared with HIJING and EPOS model calculations, and the dependence of the fluctuation measurements on the phase-space coverage is examined in the context of lattice quantum chromodynamics (LQCD) and hadron resonance gas (HRG) model estimations. The measured third-order cumulants are consistent with zero within experimental uncertainties of about 4% and are described well by LQCD and HRG predictions
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