Effect of cosmic rays on the resonant gravitational wave detector NAUTILUS at temperature T=1.5 K

The interaction between cosmic rays and the gravitational wave bar detector NAUTILUS is experimentally studied with the aluminum bar at temperature of T=1.5 K. The results are compared with those obtained in the previous runs when the bar was at T=0.14 K. The results of the run at T = 1.5 K are in agreement with the thermo-acoustic model; no large signals at unexpected rate are noticed, unlike the data taken in the run at T = 0.14 K. The observations suggest a larger efficiency in the mechanism of conversion of the particle energy into vibrational mode energy when the aluminum bar is in the superconductive status.Comment: 7 pages, 3 figures, 2 tables. Accepted by Physics Letters

Quark nuggets search using 2350 Kg gravitational waves aluminum bar detectors

The gravitational wave resonant detectors can be used as detectors of quark nuggets, like nuclearites (nuclear matter with a strange quark). This search has been carried out using data from two 2350 Kg, 2 K cooled, aluminum bar detectors: NAUTILUS, located in Frascati (Italy), and EXPLORER, that was located in CERN Geneva (CH). Both antennas are equipped with cosmic ray shower detectors: signals in the bar due to showers are continuously detected and used to characterize the antenna performances. The bar excitation mechanism is based on the so called thermo-acoustic effect, studied on dedicated experiments that use particle beams. This mechanism predicts that vibrations of bars are induced by the heat deposited in the bar from the particle. The geometrical acceptance of the bar detectors is 19.5 $\rm m^2$ sr, that is smaller than that of other detectors used for similar searches. However, the detection mechanism is completely different and is more straightforward than in other detectors. We will show the results of ten years of data from NAUTILUS (2003-2012) and 7 years from EXPLORER (2003-2009). The experimental limits we obtain are of interest because, for nuclearites of mass less than $10^{-4}$ grams, we find a flux smaller than that one predicted considering nuclearites as dark matter candidates.Comment: presented to the 33rd International Cosmic Ray Conference Rio de Janeiro 201

Low-energy features of SU(2) Yang-Mills theory with light gluinos

We report on the latest results of the low-lying spectrum of bound states in SU(2) Yang-Mills theory with light gluinos. The behavior of the disconnected contributions in the critical region is analyzed. A first investigation of a three-gluino state is also discussed.Comment: Talk presented at LATTICE99(Higgs, Yukawa, SUSY), Pisa (Italy),3 pages; to be published in Nucl. Phys. B (Proc. Suppl.

An unexpected complication of a percutaneous coronary angioplasty

Takotsubo cardiomyopathy (TCM) is characterized by transient ventricular dysfunction, classically in its apical and mid segments in the absence of coronary lesions, and is often observed after intense stressful events and occasionally associated to an acute medical illness. We describe a case of TCM associated with coronary artery disease and triggered by a percutaneous coronary angioplasty. This case highlights the concept that a medical procedure can lead, in certain conditions, to TCM and provides new interesting insights on the pathophysiology of coronary syndromes

A waiting time phenomenon for thin film equations

We prove the occurrence of a waiting time phenomenon for solutions to fourth order degenerate parabolic differential equations which model the evolution of thin films of viscous fluids. In space dimension less or equal to three, we identify a general criterion on the growth of initial data near the free boundary which guarantees that for sufficiently small times the support of strong solutions locally does not increase. It turns out that this condition only depends on the smoothness of the diffusion coefficient in its point of degeneracy. Our approach combines a new version of Stampacchia's iteration lemma with weighted energy or entropy estimates. On account of numerical experiments, we conjecture that the aforementioned growth criterion is optimal

Large mass dimuon detection in the LHCb experiment

The structure of this thesis consists of two main parts: in the first part (Detector studies), the work is focused on the performances of the Multiwire Proportional Chambers, adopted for the detection of muons in LHCb, while in the second part (Physics studies) it is focused on the study of the LHCb potentialities to improve the knowledges of the proton Parton Distribution Functions with the physical channel Z0 -> mu+ mu-. The work described in the first part is concentrated on the cosmic rays test station developed in Rome2 in order to carry out the study of the detectors performances. In particular, the cosmic rays stand allows to perform a detailed study of the detector tracking capabilities and to obtain precise measurements of the efficiency and gas gain uniformity of the produced chambers. In the second part of the thesis is reported a study of the process pp -> Z0 -> mu+ mu-. The aim of the study is to demonstrate that, in spite of the limited angular acceptance and the optimization for a different kind of physics, the number of Z0 detected at LHCb is sufficient to make profitable physics. Moreover, the foward design of the spectrometer allows to study the proton structure in a kinematic region not probed by the present experiments. A particular focus has been put on the effect of the LHCb geometrical acceptance on the cross section sensitivity to the various set of partons, simulating the process with two event generators, PYTHIA and MC@NLO