Heads of PNPI groups:
Experiments in CERN - CMS, ATLAS, LHCb, ALICE, UA9
A.A. Vorobyov (CMS and LHCb), O.L. Fedin (ATLAS), V.M. Samsonov (ALICE), Yu.M. Ivanov (UA9).
PNPI has made an extremely large contribution in construction of the collider detectors
ATLAS, CMS, LHCb and ALICE
This contribution is described in detail in the booklet
"Participation in preparation and performance of experiments at the LHC" (pdf
= 5 Mb). Due to this contribution, PNPI has become a full member of LHC experiments. PNPI scientists participate actively in data taking, share responsibilities in maintenance and operation of the detectors and participate in the data analysis. During 2010–2013,
participants have published more than 400 papers. 40 PNPI members are among authors of these papers.
A large number of physical results have been obtained, the most important being the discovery of the Higgs boson.
Important results also concern the search of contributions of “new physics” beyond the Standard Model. It has been established that such contributions are absent up to the mass of about 1 TeV.
The observation in the LHCb and CMS experiments of a very rare decay of the Bs meson into two mesons is also considered as a result of prime importance.
This decay was observed on the level of 3.2 õ10-9
in agreement with the prediction of the Standard Model.
The measured probability of this decay imposes stringent limits on possible existence of “new physics”.
This result was obtained with active participation of PNPI scientists.
The experiment UA9
has demonstrated that it is possible to cut
down the halo of the LHC proton beams using crystals developed at PNPI
) and IHEP
This result can be of great importance for increasing the LHC luminosity. It has been decided to establish a pilot collimation station
right in the LHC ring.
At present, PNPI participates in the program of the Upgrade of the CMS detector. A dedicated station is arranged for assembly and testing new CMS muon chambers. Seven PNPI engineers participate constantly in this work. Besides that, PNPI has produced a 2500-channel high-voltage system for the CMS detector and is developing a new trigger system. The contribution of PNPI to the CMS Upgrade is estimated to be about 1 million Swiss franks.
Head of the PNPI group:
Experiment PHENIX (Brookhaven, USA)
In the experiment PHENIX
, collisions of relativistic nuclei are investigated in a wide energy range from 8 GeV/nucleon up to 200 GeV/nucleon.
PNPI has made a weighty contribution to the construction of the PHENIX detector. PNPI has built the central tracker, which is one of the cardinal components of the PHENIX set-up. Also, the main magnet of unique design was fabricated in St. Petersburg for the PHENIX experiment. The PNPI group presents the obtained physical results at international conferences on behalf of the PHENIX collaboration. The experiment is going on rather successfully, and it has good perspectives for the following 5 years.
The main physical result of the PHENIX experiment is the observation of a new state of the nuclear matter – quark-gluon liquid.