Speaker
Dr
Ivan Ravasenga
(DISAT, Politecnico di Torino)
Description
ALICE (A Large Ion Collider Experiment) aims at studying the nuclear matter at high densities and temperatures characterizing a particular state of matter called Quark-Gluon Plasma (QGP), using proton-proton, proton-nucleus and nucleus-nucleus collisions at the CERN Large Hadron Collider (LHC).
The third run of LHC will start in 2021 after a shutdown of two years to allow the upgrade of both the accelerator and the experiments. In Run 3 Pb-Pb collisions will be performed at a centre of mass energy per nucleon of 5.5 TeV, with a luminosity L_int=6×10^27 cm^(-2) s^(-1). The interaction rate will be up to 50 kHz and 400 kHz for Pb-Pb and pp collisions, respectively.
To fulfil the requirements of the ALICE physics program for Run 3 of the LHC, a major upgrade of the experimental apparatus is planned for installation in 2019-2020. A key element of the ALICE upgrade is the construction of a new, ultra-light, high-resolution Inner Tracking System (ITS). The new ITS will significantly enhance the determination of the distance of closest approach to the primary vertex, the tracking efficiency at low transverse momenta, and the read-out rate capabilities, with respect to what achieved with the current detector. It will consist of seven layers equipped with silicon Monolithic Active Pixel Sensors with a pixel size of the order of 28x28 µm^2. To transmit (receive) data to (from) the sensors, Flex Printed Circuits (FPC) will be wire-bonded to the sensors themselves.
The goal is to improve the reconstruction capabilities of heavy flavour (c and b quarks) mesons and baryons. In addition, the new tracking detector will allow us to study low-mass dileptons and low-p_T charmonia at mid (e^+ e^-) rapidities.
In the talk, the first part is dedicated to the description of the present ALICE apparatus focusing the attention on the ITS, it’s operational limits and the physics motivations of its upgrade. Then, the future ITS layout will be outlined entering in the details of the various hardware components. In the second part, an overview of the expected physics performance will be shown.
Primary author
Dr
Ivan Ravasenga
(DISAT, Politecnico di Torino)
