The Effect of Tile Light Collection Reduction along Radius on the ATLAS Tile Calorimeter Uniformity

We report on the light collection non uniformity of trapezoidal scintillating tiles along radius and its consequence on the miscalibration of the middle and back longitudinal calorimeter samplings. We discuss the need to apply extra corrections to the cells response after equalization and corrections obtained by the cesium calibration system, in order to bring all three longitudinal samplings to the right electromagnetic scale

Solid-state synthesis and characterization of ferromagnetic Mn5Ge3 nanoclusters in GeO/Mn thin films

Mn5Ge3 films are promising materials for spintronic applications due to their high spin polarization and a Curie temperature above room temperature. However, non-magnetic elements such as oxygen, carbon and nitrogen may unpredictably change the structural and magnetic properties of Mn5Ge3 films. Here, we use the solid-state reaction between Mn and GeO thin films to describe the synthesis and the structural and magnetic characterization of Mn5Ge3(Mn5Ge3Oy)-GeO2(GeOx) nanocomposite materials. Our results show that the synthesis of these nanocomposites starts at 180°С when the GeO decomposes into elemental germanium and oxygen and the resulting Ge atoms immediately migrate into the Mn layer to form ferromagnetic Mn5Ge3 nanoclusters. At the same time the oxygen atoms take part in the synthesis of GeOx and GeO2 oxides and also migrate into the Mn5Ge3 lattice to form Mn5Ge3Oy Nowotny nanoclusters. Magnetic analysis assumes the general nature of the Curie temperature increase in carbon-doped Mn5Ge3Cx and Mn5Ge3Oy films. Our findings prove that not only carbon, but oxygen may contribute to the increase of the saturation magnetization and Curie temperature of Mn5Ge3-based nanostructures

Search for f1(1285)→π+π−π0f_1(1285) \to \pi^+\pi^-\pi^0 decay with VES detector

The isospin violating decay $f_1(1285)\to\pi^+\pi^-\pi^0$ has been studied at VES facility. This study is based at the statistics acquired in $\pi^- Be$ interactions at 27, 36.6 and 41 GeV/c in diffractive reaction $\pi^- N \to (f_1 \pi^-) N$. The $f_1(1285) \to \pi^+\pi^-\pi^0$ decay is observed. The ratio of decay probabilities $BR(f_1(1285) \to \pi^+\pi^-\pi^0)$ to $BR(f_1(1285) \to \eta \pi^+\pi^-) \cdot BR(\eta \to \gamma\gamma)$ is $\sim\:1.4$.Comment: 10 pages, 8 figures, presented at XII Conference on Hadron Spectroscop

Calibration of ATLAS Tile Calorimeter at Electromagnetic Scale

In this paper we summarize the measurement of the electromagnetic (EM) scale calibration constant for 11% of the Tile Calorimeter modules exposed to electron and muon test beams at CERN SPS accelerator. The Tile Calorimeter modules are currently installed in the ATLAS detector. The analysis presented in this paper takes into account the recent improvements in the Tile Calorimeter cesium calibration, charge injection system calibration and Fit Method energy reconstruction. The overall conversion factor between the measured charge and the energy deposited by measured particles for Tile Calorimeter cells is $1.050pm0.003$~pC/GeV, with spread of $2.4pm0.1$%. We discuss in detail the sources of uncertainties of EM scale calibration constant. We also show, that after inter-calibrating all the Tile Calorimeter cells with a~radioactive cesium source and setting the EM scale in the first calorimeter sampling with electron beams, the values of signals measured in the second and third calorimeter sampling need to be increased by 1--9% to keep the EM scale uniform in the whole calorimeter