Current status and perspectives of the LUCIFER experiment

Abstract The quest for Neutrinoless Double Beta Decay (0 ν DBD) represents one of the most promising ways to investigate the neutrino mass nature, Dirac or Majorana. A convincing detection claim demands for detectors with excellent energy resolution and almost zero background in the energy region of interest. These features can be obtained with the approach of the LUCIFER project, funded by an European grant, which is based on the double readout of the heat and scintillation light produced by ZnSe scintillating bolometers. The resulting identification and rejection of the α interactions, as well as the large Q-value of the emitter, will guarantee a background lower than 10 −3 counts/keV/kg/y in the energy region of the 0 ν DBD of 82 Se, an order of magnitude lower with respect to the present generation experiments. Despite the small mass of ∼17 kg, LUCIFER will reach a 90% CL sensitivity of 0.6 × 10 26 y on the half-life of the decay. We describe the current status of the project, including results of the recent R&D activity

A NuSTAR observation of the fast symbiotic nova V745 Sco in outburst

The fast recurrent nova V745 Sco was observed in the 3-79 keV X-rays band with NuSTAR 10 days after the optical discovery. The measured X-ray emission is consistent with a collisionally ionized optically thin plasma at temperature of about 2.7 keV. A prominent iron line observed at 6.7 keV does not require enhanced iron in the ejecta. We attribute the X-ray flux to shocked circumstellar material. No X-ray emission was observed at energies above 20 keV, and the flux in the 3-20 keV range was about 1.6 $\times$ 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$. The emission measure indicates an average electron density of order of 10$^7$ cm$^{-3}$. The X-ray flux in the 0.3-10 keV band almost simultaneously measured with Swift was about 40 times larger, mainly due to the luminous central supersoft source emitting at energy below 1 keV. The fact that the NuSTAR spectrum cannot be fitted with a power law, and the lack of hard X-ray emission, allow us to rule out Comptonized gamma rays, and to place an upper limit of the order of 10$^{-11}$ erg cm$^{-2}$ s$^{-1}$ on the gamma-ray flux of the nova on the tenth day of the outburst.Comment: in press in Monthly Notices of the Royal Astronomical Society, 201

Measurements of the Cerenkov light emitted by a TeO2 crystal

Bolometers have proven to be good instruments to search for rare processes because of their excellent energy resolution and their extremely low intrinsic background. In this kind of detectors, the capability of discriminating alpha particles from electrons represents an important aspect for the background reduction. One possibility for obtaining such a discrimination is provided by the detection of the Cerenkov light which, at the low energies of the natural radioactivity, is only emitted by electrons. In this paper, the results of the analysis of the light emitted by a TeO2 crystal at room temperature when transversed by a cosmic ray are reported. Light is promptly emitted after the particle crossing and a clear evidence of its directionality is also found. These results represent a strong indication that Cerenkov light is the main, if not even the only, component of the light signal in a TeO2 crystal. They open the possibility to make large improvements in the performance of experiments based on this kind of material

The X-ray emission from Nova V382 Velorum: I. The hard component observed with BeppoSAX

We present BeppoSAX observations of Nova Velorum 1999 (V382 Vel), done in a broad X-ray band covering 0.1-300 keV only 15 days after the discovery and again after 6 months. The nova was detected at day 15 with the BeppoSAX instruments in the energy range 1.8-10 keV and we attribute the emission to shocks in the ejecta. The plasma temperature was kT~6 keV and the unabsorbed flux was F(x)~4.3 x 10(-11) erg/cm**2/s. The nebular material was affected by high intrinsic absorption of the ejecta. 6 months after after the outburst, the intrinsic absorption did not play a role, the nova had turned into a bright supersoft source, and the hot nebular component previously detected had cooled to a plasma temperature kT<=1 keV. No emission was detected in either observation above 20 keV.Comment: 1 tex file, 2 figures as .ps, and 1 .sty file of MNRA

The cardiovascular risk of young women with polycystic ovary syndrome: an observational, analytical, prospective case-control study

To evaluate the cardiovascular risk of polycystic ovary syndrome (PCOS), we investigated lipid profile, metabolic pattern, and echocardiography in 30 young women with PCOS and 30 healthy age- and body mass index (BMI)-matched women. PCOS women had higher fasting glucose and insulin levels, homeostasis model assessment score of insulin sensitivity, total cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) levels, and TC/high density lipoprotein cholesterol (HDL-C) ratio and lower HDL-C levels than controls. Additionally, PCOS women had higher left atrium size (32.0 +/- 4.9 vs. 27.4 +/- 2.1 mm; P &lt; 0.0001) and left ventricular mass index (80.5 +/- 18.1 vs. 56.1 +/- 5.4 g/m(2); P &lt; 0.0001) and lower left ventricular ejection fraction (64.4 +/- 4.1 vs. 67.1 +/- 2.6%; P = 0.003) and early to late mitral flow velocity ratio (1.6 +/- 0.4 vs. 2.1 +/- 0.2; P &lt; 0.0001) than controls. When patients and controls were grouped according to BMI [normal weight (BMI, &gt;18 and &lt;25 kg/m(2)), overweight (BMI, 25.1-30 kg/m(2)), and obese (BMI, &gt;30 kg/m(2))], the differences between PCOS women and controls were maintained in overweight and obese women. In normal weight PCOS women, a significant increase in left ventricular mass index and a decrease in diastolic filling were observed, notwithstanding no change in TC, LDL-C, HDL-C, TC/HDL-C ratio, and TG compared with controls. In conclusion, our data show the detrimental effect of PCOS on the cardiovascular system even in young women asymptomatic for cardiac disease

Status and plans of the LUCIFER Experiment

Neutrinoless Double Beta Decay searches are the only way to give an answer to the neutrino mass nature, Dirac or Majorana. These experiments are extremely delicate and the greatest obstacle to improve their sensitivity is the background level that can be achieved. LUCIFER is a project, financed by a ERC-AdG, that would like to build a demonstrator of a technique based on the double read-out (scintillation light + heat) of ZnSe crystals used as bolometers. The goal is to reach a background lower than 0.001counts/kg/keV/year. Along the way we would like to learn how practical is the enrichment of Se into 82Se, how efficient is the process of crystallization and how radiopurethe crystals can be grown. In this talk we will discuss the properties of ZnSe crystals and sketch the layout of the project

Effects of Metformin With or Without Supplementation With Folate on Homocysteine Levels and Vascular Endothelium of Women With Polycystic Ovary Syndrome

OBJECTIVE: To evaluate whether the administration of metformin exerts any effects on serum homocysteine (Hcy) levels in patients with polycystic ovary syndrome (PCOS) and whether supplementation with folate enhances the positive effects of metformin on the structure and function of the vascular endothelium. RESEARCH DESIGN AND METHODS: A total of 50 patients affected by PCOS, without additional metabolic or cardiovascular diseases, were enrolled in a prospective nonrandomized placebo-controlled double-blind clinical study. They were grouped into two treatment arms that were matched for age and BMI. Patients were treated with a 6-month course of metformin (1,700 mg daily) plus folic acid (400 microg daily; experimental group, n = 25) or placebo (control group, n = 25). Complete hormonal and metabolic patterns, serum Hcy, folate, vitamin B12, endothelin-1 levels, brachial artery diameter at the baseline (BAD-B) and after reactive hyperemia (BAD-RH), flow-mediated dilation, and intima-media thickness in both common carotid arteries were evaluated. RESULTS: After treatment, a significant increase in serum Hcy levels was observed in the control group compared with the baseline values and the experimental group. A beneficial effect was observed in the concentrations of BAD-B, BAD-RH, flow-mediated dilation, intima-media thickness, and serum endothelin-1 in both groups. However, the results were improved more significantly in the experimental group than in the control subjects. CONCLUSIONS: Metformin exerts a slight but significant deleterious effect on serum Hcy levels in patients with PCOS, and supplementation with folate is useful to increase the beneficial effect of metformin on the vascular endothelium

Measurements and optimization of the light yield of a TeO2_2 crystal

Bolometers have proven to be good instruments to search for rare processes because of their excellent energy resolution and their extremely low intrinsic background. In this kind of detectors, the capability of discriminating alpha particles from electrons represents an important aspect for the background reduction. One possibility for obtaining such a discrimination is provided by the detection of the Cherenkov light which, at the low energies of the natural radioactivity, is only emitted by electrons. This paper describes the method developed to evaluate the amount of light produced by a crystal of TeO$_2$ when hit by a 511 keV photon. The experimental measurements and the results of a detailed simulation of the crystal and the readout system are shown and compared. A light yield of about 52 Cherenkov photons per deposited MeV was measured. The effect of wrapping the crystal with a PTFE layer, with the aim of maximizing the light collection, is also presented