Discharge probability studies with multi-GEM detectors for the ALICE TPC Upgrade

A large Time Projection Chamber (TPC) is the main device for tracking and charged-particle identification in the ALICE experiment at the CERN LHC. After the second long shutdown in 2019-2020, the LHC will deliver Pb beams colliding at an interaction rate of up to 50 kHz, which is about a factor of 50 above the present readout rate of the TPC. To fully exploit the LHC potential, the TPC readout chambers will be upgraded with Gas Electron Multiplier (GEM) technology. To assure stable behaviour of the upgraded chambers in the harsh LHC environment, a dedicated R&D programme was launched in order to optimize GEM stack geometry and its high voltage configuration with respect to electric discharges. We present a summary of discharge probability measurements performed with 3- and 4-GEM prototypes irradiated with highly ionising alpha particles.Comment: Submitted to PoS 6 pages, 4 figure

Monocyte Chemoattractant Protein-1− 2518 A/G Single Nucleotide Polymorphism Might Be Associated with Renal Disease and Thrombocytopenia of SLE

There is conflicting evidence on the contribution of the MCP-1 −2518 A>G (rs 1024611) polymorphism to SLE incidence and clinical manifestations. We examined the prevalence of the MCP-1 −2518 A>G polymorphism in SLE patients (n = 199) and controls (n = 250) in Poland. We did not observe a significant difference in the distribution of MCP-1 −2518 A>G polymorphic variants in patients with SLE and healthy individuals. However, we found an association between the GG versus AG and AA genotypes as well as the AG and GG versus AA genotypes with renal manifestations of SLE OR = 3.614 (1.123–11.631, P = 0.0345) and OR = 2.297 (1.301–4.057, P = 0.0046), respectively. We also observed that the MCP-1 AG and GG -genotypes contribute to the occurrence of thrombocytopenia in SLE patients OR = 2.618 (1.280–5.352, P = 0.0089). Our observations indicate that either MCP-1 −2518 G variant can be associated with some clinical findings in patients with SLE

Measurement of K∗(892)0K^*(892)^0 and K0K^0 mesons in Al+Al collisions at 1.9AA GeV

New measurement of sub-threshold $K^*(892)^0$ and $K^0$ production is presented. The experimental data complete the measurement of strange particles produced in Al+Al collisions at 1.9$A$ GeV measured with the FOPI detector at SIS/GSI. The $K^*(892)^0$ / $K^0$ yield ratio is found to be $0.0315\pm 0.006 (\mathrm{stat.})\pm 0.012 (\mathrm{syst.})$ and is in good agreement with the UrQMD model prediction. These measurements provide information on in-medium cross section of $K^+$ - $\pi^-$ fusion which is the dominant process on sub-threshold $K^*(892)^0$ production.Comment: 5 pages, 4 figures, accepted for publication in Phys. Rev.