80 research outputs found
Light vector meson production at the LHC with the ALICE detector
The measurement of light vector meson production (\rho, \omega, \phi) in pp
collisions provides insight into soft Quantum Chromodynamics (QCD) processes in
the LHC energy range. Calculations in this regime are based on QCD inspired
phenomenological models that must be tuned to the data. Moreover, light vector
meson production provides a reference for high-energy heavy-ion collisions.
A measurement of the \phi and \omega differential cross sections as performed
by the ALICE experiment in pp collisions at 7 TeV and of the \phi cross section
in pp collisions at 2.76 TeV through their decay to muon pairs and in the
rapidity interval 2.5 < y < 4.Comment: 2 pages, 2 figures. proceedings for the conference: Hard Probes 201
Light vector meson production at forward rapidity in pp collisions at the LHC with the ALICE detector
Low-mass vector mesons (ρ,ω and Φ) give us information on the hot and dense state of strongly interacting matter produced in heavy ion collisions. In fact, in the QGP an enhancement of the strange particle production should be present (strangeness enhancement), which means a Nø/Nρ+ω ratio increasing in A-A collisions with respect to pp colli-
sions; pp collisions provide a reference for these studies. Vector meson production in pp collisions is also useful by itself, to study soft Quantum ChromoDynamics (QCD) in the LHC energy range, since calculations in this regime are based on QCD inspired phenomenological models that
must be tuned to the data. The ALICE experiment at the LHC can access vector mesons produced at forward rapidity through their decays in muon pairs. I show the ratio
Nø/Nρ+ω vs pT , the ratios σρ/σω and σΦ/σω, and the Φ and ω pT and rapidity dierential cross sections for the data sample at 7 TeV. For the data sample at 2.76 TeV, because of the limited statistics, I have show only the Nø/Nρ+ω ratio and Φ and ω integrated cross sections
Light vector meson production at forward rapidity in pp collisions at the LHC with the ALICE detector
Low-mass vector mesons (ρ,ω and Φ) give us information on the hot and dense state of strongly interacting matter produced in heavy ion collisions. In fact, in the QGP an enhancement of the strange particle production should be present (strangeness enhancement), which means a Nø/Nρ+ω ratio increasing in A-A collisions with respect to pp colli-
sions; pp collisions provide a reference for these studies. Vector meson production in pp collisions is also useful by itself, to study soft Quantum ChromoDynamics (QCD) in the LHC energy range, since calculations in this regime are based on QCD inspired phenomenological models that
must be tuned to the data. The ALICE experiment at the LHC can access vector mesons produced at forward rapidity through their decays in muon pairs. I show the ratio
Nø/Nρ+ω vs pT , the ratios σρ/σω and σΦ/σω, and the Φ and ω pT and rapidity dierential cross sections for the data sample at 7 TeV. For the data sample at 2.76 TeV, because of the limited statistics, I have show only the Nø/Nρ+ω ratio and Φ and ω integrated cross sections
Colorectal Cancer Stage at Diagnosis Before vs During the COVID-19 Pandemic in Italy
IMPORTANCE Delays in screening programs and the reluctance of patients to seek medical
attention because of the outbreak of SARS-CoV-2 could be associated with the risk of more advanced
colorectal cancers at diagnosis.
OBJECTIVE To evaluate whether the SARS-CoV-2 pandemic was associated with more advanced
oncologic stage and change in clinical presentation for patients with colorectal cancer.
DESIGN, SETTING, AND PARTICIPANTS This retrospective, multicenter cohort study included all
17 938 adult patients who underwent surgery for colorectal cancer from March 1, 2020, to December
31, 2021 (pandemic period), and from January 1, 2018, to February 29, 2020 (prepandemic period),
in 81 participating centers in Italy, including tertiary centers and community hospitals. Follow-up was
30 days from surgery.
EXPOSURES Any type of surgical procedure for colorectal cancer, including explorative surgery,
palliative procedures, and atypical or segmental resections.
MAIN OUTCOMES AND MEASURES The primary outcome was advanced stage of colorectal cancer
at diagnosis. Secondary outcomes were distant metastasis, T4 stage, aggressive biology (defined as
cancer with at least 1 of the following characteristics: signet ring cells, mucinous tumor, budding,
lymphovascular invasion, perineural invasion, and lymphangitis), stenotic lesion, emergency surgery,
and palliative surgery. The independent association between the pandemic period and the outcomes
was assessed using multivariate random-effects logistic regression, with hospital as the cluster
variable.
RESULTS A total of 17 938 patients (10 007 men [55.8%]; mean [SD] age, 70.6 [12.2] years)
underwent surgery for colorectal cancer: 7796 (43.5%) during the pandemic period and 10 142
(56.5%) during the prepandemic period. Logistic regression indicated that the pandemic period was
significantly associated with an increased rate of advanced-stage colorectal cancer (odds ratio [OR],
1.07; 95%CI, 1.01-1.13; P = .03), aggressive biology (OR, 1.32; 95%CI, 1.15-1.53; P < .001), and stenotic
lesions (OR, 1.15; 95%CI, 1.01-1.31; P = .03).
CONCLUSIONS AND RELEVANCE This cohort study suggests a significant association between the
SARS-CoV-2 pandemic and the risk of a more advanced oncologic stage at diagnosis among patients
undergoing surgery for colorectal cancer and might indicate a potential reduction of survival for
these patients
Measurement of transverse energy at midrapidity in Pb-Pb collisions at root s(NN)=2.76 TeV
We report the transverse energy (ET) measured with ALICE at midrapidity in Pb-Pb collisions at root s(NN) = 2.76 TeV as a function of centrality. The transverse energy was measured using identified single-particle tracks. The measurement was cross checked using the electromagnetic calorimeters and the transverse momentum distributions of identified particles previously reported by ALICE. The results are compared to theoretical models as well as to results from other experiments. The mean ET per unit pseudorapidity (eta), , in 0%-5% central collisions is 1737 +/- 6(stat.) +/- 97(sys.) GeV. We find a similar centrality dependence of the shape of as a function of the number of participating nucleons to that seen at lower energies. The growth in at the LHC energies exceeds extrapolations of low-energy data. We observe a nearly linear scaling of with the number of quark participants. With the canonical assumption of a 1 fm/c formation time, we estimate that the energy density in 0%-5% central Pb-Pb collisions at root s(NN) = 2.76 TeV is 12.3 +/- 1.0 GeV/fm(3) and that the energy density at the most central 80 fm(2) of the collision is at least 21.5 +/- 1.7 GeV/fm(3). This is roughly 2.3 times that observed in 0%-5% central Au-Au collisions at root s(NN) = 200 GeV.Peer reviewe
D-meson production in p-Pb collisions at root S-NN=5.02 TeV and in pp collisions at root S=7 TeV
Peer reviewe
Correlated Event-by-Event Fluctuations of Flow Harmonics in Pb-Pb Collisions at root S-NN=2.76 TeV
Peer reviewe
J/Psi suppression at forward rapidity in Pb-Pb collisions at root s(NN)=5.02 TeV
The inclusive J/Psi production has been studied in Pb-Pb and pp collisions at the centre-of-mass energy per nucleon pair root sNN= 5.02TeV, using the ALICE detector at the CERN LHC. The J/Psi meson is reconstructed, in the centre-of-mass rapidity interval 2.5 <y <4and in the transverse- momentum range p(T)<12GeV/c, via its decay to a muon pair. In this Letter, we present results on the inclusive J/Psi cross section in pp collisions at root s= 5.02TeV and on the nuclear modification factor R-AA. The latter is presented as a function of the centrality of the collision and, for central collisions, as a function of the transverse momentum p(T) of the J/Psi. The measured R-AA values indicate a suppression of the J/Psi in nuclear collisions and are then compared to our previous results obtained in Pb-Pb collisions at root sNN= 2.76TeV. The ratio of the R-AA values at the two energies is also computed and compared to calculations of statistical and dynamical models. The numerical value of the ratio for central events (0-10% centrality) is 1.17 +/- 0.04( stat)+/- 0.20(syst). In central events, as a function of p(T), a slight increase of R-AA with collision energy is visible in the region 2 <p(T)<6GeV/c. Theoretical calculations qualitatively describe the measurements, within uncertainties. (C) 2017 The Author. Published by Elsevier B.V.Peer reviewe
Multipion Bose-Einstein correlations in pp, p-Pb, and Pb-Pb collisions at energies available at the CERN Large Hadron Collider
Peer reviewe
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