Particle Physics (CSN1)

ATLAS


ATLAS is a particle physics experiment at the Large Hadron Collider (LHC) at CERN which is the world's highest energy proton-proton collider presently running. LHC begins operation in 2009 at the center of mass energy of 900 GeV and 2.36 GeV and since then has delivered p-p collisions at 7, 8 and 13 TeV. The ATLAS detector is searching for new discoveries in the head-on collisions of protons of extraordinarily high energy and will increase our knowledge of the basic forces that have shaped our universe since the beginning of time. It has already discovered the source of electroweak symmetry breaking (the Higgs boson) in 2012 and it has searched for new forms of matter such as supersymmetric states, putting limits on their masses. The group of INFN-Roma Tor Vergata has contributed to the construction of the RPC trigger chambers and to the front-end electronics of the ATLAS muon system. The INFN-Roma Tor Vergata group has developed expertise and is working on top quark physics, bottom, charm, and Higgs boson physics and searches for deviations from the Standard Model.


 

GMINUS2

The Muon g-2 Fermilab experiment (FNAL E989) plans to measure the muon anomalous magnetic moment  with a precision of 0.14 parts per million, about 4 times better than the present world-average (dominated by the result of the BNL E821 experiment). The aim is to compare this measurement with the Standard Model prediction, which has a precision comparable to the present experimental one, and differs from the experimental value by about  3σ.

The E989 collaboration includes several participating Italian research institutions, which have the task to design, construct and operate the laser calibration system for the experiment electro-magnetic calorimeter. This system precisely monitors the gain the calorimeter, whose understanding corresponds to a significant systematic uncertainty of the measurement. With respect to the BNL experiment, the Fermilab experiment plans to reduce this sistematic contribution from 120 parts per billion to 20 parts per billion, the largest planned reduction of any single systematic contribution.

The Roma Tor Vergata group is mainly involved in the data analysis.


 


KLOE

The KLOE -2experiment, which ended his data acquisition period  in the 30 March 2018,  was located on the DAFNE collider in Frascati, which is a e+ e- storage ring at high luminosity (1033 cm-2 s-1) and energy around the Phi resonance (1020 MeV)

One of the main objectives of KLOE-2 collaboration is the study of  quantum interference phenomena of neutral K-mesons produced at DAFNE together with the very high precision study of the intrinsic properties of particles of matter (kaons) compared to those. The apparatus, optimized to detect charged and neutral decays of both KS and KL mesons,  was composed of a large-volume drift chamber surrounding the beam interaction region and an electromagnetic calorimeter. A superconducting coil with an iron return yoke was able to provide a longitudinal magnetic field, needed to measure the charged particle momentum.

Ended the data collection campaign, the Kloe-2 collaboration is now engaged in the analysis of the acquired data.

The two detectors HET (High Energy Tagger) realized by the KLOE-2 Tor Vergata group continue to be used as luminosity measurements detectors for DAFNE e+ e- beams.



LHCB


The LHCb experiment is a single-arm spectrometer for the forward direction designed to fully exploit the B-physics potential of the Large Hadron Collider under construction at CERN. At a design luminosity of about 2x10^32 cm-2 s-1, LHC is expected to yield about 10^12 b pairs per year, mostly concentrated at low polar angles with respect to the axis of the colliding beams. The main goal of LHCb is to provide accurate measurement of all the angles of the Unitarity Triangle(s), eventually demonstrating the need for new physics beyond the Standard Model. The LHCb apparatus has been designed to trigger efficiently on both leptonic and hadronic B decays and to allow particle identification capabilities - in particular pi/K separation - over the whole momentum spectra of B decay products. The detector consists of a high-performance vertex detector, a multi-station tracking system integrated by a 4 Tm dipole magnet for charged particle momentum measurement, two RICH detectors for particle identification, a calorimeter system for photon/electron identification and neutral particle energy measurement and a muon system for muon identification. The Roma Tor Vergata group is involved in the design and construction of the muon system.



NA62


The NA62 experiment aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar at the CERN SPS to make a test of the Standard Model in the flavour sector and to deepen the knowledge of the CKM matrix. The Roma Tor Vergata group is involved in the design and construction of the trigger electronics of the liquid krypton electromagnetic calorimeter.