LHCb: Not just a precision experiment but also a detector ready for discoveries

The first proton run has confirmed that LHCb has powerful capabilities in the field of flavour physics and that many possible signatures of non-Standard Model effects are within the experiment's reach. Furthermore, this run has confirmed that LHCb is able to make important contributions beyond the flavour sector. The collaboration is working on a Letter of Intent for an upgrade, which will take advantage of the open geometry of the experiment, and will aim at improved sensitivity both in the flavour sector and in a wider physics programme.


Unlike ATLAS and CMS, LHCb does not have a cylindrical geometry. Rather, it is laid out horizontally along the beam line. This layout prevented the collaboration from testing the detector with cosmic rays prior to starting to collect data from the LHC collisions. However, despite these more challenging initial conditions, LHCb was soon able to demonstrate excellent performance during the LHC’s first proton run. “Just a few years ago, we could not have predicted that our detector would perform so well”, says Andrei Golutvin, LHCb spokesperson. “In a very short space of time, we have been able to learn a lot about all our sub-detectors”.

In order to maximize the integrated luminosity provided by the LHC during the 2010 run, LHCb had to cope with a much higher pile-up compared to its nominal conditions. “We managed to work well even in this very difficult environment, where the particle track reconstruction and the data processing weren’t what we had planned”, says Golutvin.

With the 40 inverse picobarns of integrated luminosity collected by the experiment, the collaboration is already confident of achieving a very high sensitivity in the field of flavour physics, with the possibility of making interesting discoveries. “Our experiment is well equipped to perform high-sensitivity studies within our unique acceptance in the forward direction”, explains Golutvin. “We have already performed new measurements of the production cross-section of beauty and charm quarks, which tests QCD at the centre-of-mass energy of 7 TeV, which nobody had done before. Looking at the good results we are obtaining, we really think that if the new physics has significant effects on some of the decays we consider to be more sensitive, we’ll certainly see them in the coming months. LHCb is not just a precision experiment but also an experiment of discovery”, concludes Golutvin.

LHCb will not run with ions. The collaboration will concentrate on the analysis of the data collected so far, and during the Christmas technical stop will implement a concentrated programme of minor adjustments needed to get the detector ready for the restart in January. In the medium term, the collaboration also plans to submit a Letter of Intent for the experiment’s upgrade. “Thanks to its open geometry, LHCb is much simpler to modify and adapt than other detectors. We are thinking of implementing a fully software-based trigger and are ready to re-optimize the current layout if we see that there are interesting effects in the forward direction. We can react very quickly and we now believe that we have to extend our physics programme beyond the flavour sector to a more complete set of studies in the forward direction”, concludes Golutvin.

by CERN Bulletin