Low-energy resonances in the 18O (p,Υ) 19F reaction

Background: Shell hydrogen burning during the asymptotic giant branch (AGB) phase through the oxygen isotopes has been indicated as a key process that is needed to understand the observed 18O/16O relative abundance in presolar grains and in stellar atmospheres. This ratio is strongly influenced by the relative strengths of the reactions 18O(p,\u3b1) 15N and 18O(p,\u3b3 ) 19F in low-mass AGB stars. While the former channel has been the focus of a large number of measurements, the (p,\u3b3 ) reaction path has only recently received some attention and its stellar reaction rate over a wide temperature range rests on only one measurement. Purpose: Our aim is the direct measurement of states in 19F as populated through the reaction 18O(p,\u3b3 ) 19F to better determine their influence on the astrophysical reaction rate, and more generally to improve the understanding of the nuclear structure of 19F. Method: Branchings and resonance strengths were measured in the proton energy range Elab p = 150\u2013400 keV, using a high-purity germanium detector inside a massive lead shield. The measurement took place in the ultralow- background environment of the Laboratory for Underground Nuclear Astrophysics (LUNA) experiment at the Gran Sasso National Laboratory, leading to a highly increased sensitivity. Results: The uncertainty of the \u3b3 branchings and strengths was improved for all four resonances in the studied energy range; many new transitions were observed in the case of the 334 keV resonance, and individual \u3b3 decays of the 215 keV resonance were measured for the first time. In addition a number of transitions to intermediate states that decay through \u3b1 emission were identified. The strengths of the observed resonances are generally in agreement with literature values. Conclusions: Our measurements substantially confirm previous determinations of the relevant resonance strengths. Therefore the 18O(p,\u3b3 ) 19F reaction rate does not change with respect to the reaction rate reported in the compilations commonly adopted in the extant computations of red-giant branch and AGB stellar models. Nevertheless, our measurements definitely exclude a nonstandard scenario for the fluorine nucleosynthesis and a nuclear physics solution for the 18O depletion observed in Group 2 oxygen-rich stardust grains

Elliptic flow of identified hadrons in Pb-Pb collisions at 1asNN = 2.76 TeV

The elliptic flow coefficient (v2) of identified particles in Pb-Pb collisions at 1asNN = 2.76 TeV was measured with the ALICE detector at the Large Hadron Collider (LHC). The results were obtained with the Scalar Product method, a two-particle corre- lation technique, using a pseudo-rapidity gap of | 06\u3b7| > 0.9 between the identified hadron under study and the reference particles. The v2 is reported for \u3c0\ub1, K\ub1, K0S, p+p, \u3c6, \u39b+\u39b, \u39e 12+\u39e+ and \u3a9 12+\u3a9+ in several collision centralities. In the low transverse momentum (pT) region, pT 3 GeV/c

Centrality dependence of high-pT D meson suppression in Pb-Pb collisions at 1asNN = 2.76 TeV

The nuclear modification factor, RAA, of the prompt charmed mesons D0, D+ and D 17+, and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at a centre-of-mass energy 1asNN = 2.76 TeV in two transverse momentum intervals, 5 < pT < 8GeV/c and 8 < pT < 16GeV/c, and in six collision centrality classes. The RAA shows a maximum suppression of a factor of 5\u20136 in the 10% most central collisions. The suppression and its centrality dependence are compatible within uncertainties with those of charged pions. A comparison with the RAA of non-prompt J/\u3c8 from B meson decays, measured by the CMS Collaboration, hints at a larger suppression of D mesons in the most central collisions

Centrality dependence of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02 TeV

We present a measurement of inclusive J/\u3c8 production in p-Pb collisions at 1asNN = 5.02TeV as a function of the centrality of the collision, as estimated from the energy deposited in the Zero Degree Calorimeters. The measurement is performed with the ALICE detector down to zero transverse momentum, pT, in the backward ( 124.46 < ycms < 122.96) and forward (2.03 < ycms < 3.53) rapidity intervals in the dimuon decay channel and in the mid-rapidity region ( 121.37 < ycms < 0.43) in the dielectron decay channel. The backward and forward rapidity intervals correspond to the Pb-going and p-going direction, respectively. The pT-differential J/\u3c8 production cross section at backward and forward rapidity is measured for several centrality classes, together with the corresponding average pT and pT2 values. The nuclear modification factor is presented as a function of centrality for the three rapidity intervals, and as a function of pT for several centrality classes at backward and forward rapidity. At mid- and forward rapidity, the J/\u3c8 yield is suppressed up to 40% compared to that in pp interactions scaled by the number of binary collisions. The degree of suppression increases towards central p-Pb collisions at forward rapidity, and with decreasing pT of the J/\u3c8. At backward rapidity, the nuclear modification factor is compatible with unity within the total uncertainties, with an increasing trend from peripheral to central p-Pb collisions

Decay of Er156 compound nucleus

Charged particles and high energy \u3b3 rays from the decay of the 156Er compound nucleus populated at Ex=47 MeV excitation energy by the 12C+144Sm and 64Ni+92Zr reactions have been measured to study possible nonstatistical or entrance channel effects. The experimental spectra and published evaporation residue and neutron data are compared with statistical model calculations. The comparison shows that the statistical model with standard parametrization of level density and yrast lines describes reasonably well the bulk of experimental observables but not the shape of neutron spectra if account is taken of the enhancement factor for E2 transitions. The discrepancies between experimental data and model calculations are discussed

Direct Capture Cross Section and the Ep = 71 and 105 keV Resonances in the 22Ne(p,\u3b3)23Na Reaction

The 22Ne(p,\u3b3)23Na reaction, part of the neon-sodium cycle of hydrogen burning, may explain the observed anticorrelation between sodium and oxygen abundances in globular cluster stars. Its rate is controlled by a number of low-energy resonances and a slowly varying nonresonant component. Three new resonances at Ep = 156.2, 189.5, and 259.7 keV have recently been observed and confirmed. However, significant uncertainty on the reaction rate remains due to the nonresonant process and to two suggested resonances at Ep = 71 and 105 keV. Here, new 22Ne(p,\u3b3)23Na data with high statistics and low background are reported. Stringent upper limits of 6 7 10 1211 and 7 7 10 1211 eV (90% confidence level), respectively, are placed on the two suggested resonances. In addition, the off-resonant S factor has been measured at unprecedented low energy, constraining the contributions from a subthreshold resonance and the direct capture process. As a result, at a temperature of 0.1 GK the error bar of the 22Ne(p,\u3b3)23Na rate is now reduced by 3 orders of magnitud

A high-efficiency gas target setup for underground experiments, and redetermination of the branching ratio of the 189.5 keV22Ne(p,gamma)23Na resonance

The experimental study of nuclear reactions of astrophysical interest is greatly facilitated by a low-background, high-luminosity setup. The Laboratory for Underground Nuclear Astrophysics (LUNA) 400 kV accelerator offers ultra-low cosmic-ray induced background due to its location deep underground in the Gran Sasso National Laboratory (INFN-LNGS), Italy, and high intensity, 250\u2013500 \u3bcA, proton and alfa ion beams. In order to fully exploit these features, a high-purity, recirculating gas target system for isotopically enriched gases is coupled to a high-efficiency, six-fold optically segmented bismuth germanate (BGO) gamma-ray detector. The beam intensity is measured with a beam calorimeter with constant temperature gradient. Pressure and temperature measurements have been carried out at several positions along the beam path, and the resultant gas density profile has been determined. Calibrated gamma-intensity standards and the wellknown Ep = 278 keV 14N(p,gamma)15O resonance were used to determine the gamma-ray detection efficiency and to validate the simulation of the target and detector setup. As an example, the recently measured resonance at Ep = 189.5keV in the 22Ne(p,gamma)23Na reaction has been investigated with high statistics, and the gamma-decay branching ratios of the resonance have been determined

Hypernuclear weak decay studies with FINUDA

37reservedmixedM. Agnello;L. Benussi;M. Bertani;H.C. Bhang;G. Bonomi;E. Botta;M. Bregant;T. Bressani;S. Bufalino;L. Busso;D. Calvo;P. Camerini;B. Dalena;F. De Mori;G. DʼErasmo;F.L. Fabbri;A. Feliciello;A. Filippi;E.M. Fiore;H. Fujioka;P. Gianotti;N. Grion;V. Lucherini;S. Marcello;N. Mirfakhrai;F. Moia;P. Montagna;O. Morra;T. Nagae;H. Outa;A. Pantaleo;V. Paticchio;S. Piano;R. Rui;G. Simonetti;R. Wheadon;A. ZenoniM., Agnello; L., Benussi; M., Bertani; H. C., Bhang; Bonomi, Germano; E., Botta; M., Bregant; T., Bressani; S., Bufalino; L., Busso; D., Calvo; P., Camerini; B., Dalena; F., De Mori; G., Dʼerasmo; F. L., Fabbri; A., Feliciello; A., Filippi; E. M., Fiore; H., Fujioka; P., Gianotti; N., Grion; V., Lucherini; S., Marcello; N., Mirfakhrai; F., Moia; P., Montagna; O., Morra; T., Nagae; H., Outa; A., Pantaleo; V., Paticchio; S., Piano; R., Rui; G., Simonetti; R., Wheadon; Zenoni, Ald

The FINUDA experiment at DAPHNE

The forthcoming FINUDA experiment at DANE is presented

Performance of PSI, CURB-65, and SCAP scores in predicting the outcome of patients with community-acquired and healthcare-associated pneumonia

The objective was to compare three score systems, pneumonia severity index (PSI), the Confusion-Urea-Respiratory Rate-Blood pressure-65 (CURB-65), and severe community-acquired pneumonia (SCAP), for prediction of the outcomes in a cohort of patients with community-acquired (CAP) and healthcare-associated pneumonia (HCAP). Large multi-center, prospective, observational study was conducted in 55 hospitals. HCAP patients were included in the high classes of CURB-65, PSI and SCAP scores have a mortality rate higher than that of CAP patients. HCAP patients included in the low class of the three severity rules have a significantly higher incidence of adverse events, including development of septic shock, transfer into an ICU, and death (p < 0.01). At multivariate Cox regression analysis, inclusion in the severe classes of PSI, CURB-65, or SCAP scores and receipt of an empirical therapy not adherent to international guidelines prove to be risk factors independently associated with poor outcome. PSI, CURB-65, and SCAP score have a good performance in patients with CAP but are less useful in patients with HCAP, especially in patients classified in the low-risk classes