#### Title:

Measuring matter anti-matter asymmetry at LHCb

PHD

Glasgow U.

13-11-2007

#### Description:

The main focus of the LHCb experiment, located at the Large Hadron Collider at CERN, is the study of CP asymmetry, believed to be one of the causes of the matter-antimatter asymmetry of the present universe. The origin of CP violation in the Standard Model is through the so-called CKM matrix that describes the level of quantum mechanical mixing amongst quarks. Because the CKM matrix contains a complex term, this causes a small time-dependent asymmetry between the decay of particles and their anti-matter counterparts. This effect will be particularly strong in the decay of B and anti-B mesons (particles that have a B or "bottom" quark).

While CP violations from the decay of B mesons have already been observed, one parameter of the theory (the unitarity angle gamma) is particularly poorly known. One of the main aims of the LHCb experiment is to measure this angle gamma in a variety of decay channels, and search for New Physics by comparing channels that are sensitive to new CP violating mechanisms with those that mainly measure the Standard Model gamma.

A leading candidate for such a measurement comes from the comparison of time dependent asymmetries in the decays of channels Bd->D-pi+ and Bs->Ds-K+. This research would culminate in a measurement of the Standard Model value of gamma with unprecedented accuracy, which can be compared with a measurement of gamma sensitive to New Physics. Also, as part of this programme of research, an unbiased measurement of the lifetime of the B mesons will also be extracted resulting in the world"s best measurement of the Bd and Bs lifetimes.

You will work within the Glasgow LHCb group of seven research staff and four PhD students. Your main activities will include the analysis of data and running and operating the experiment. You will travel to CERN in Geneva regularly, and spend a period of around one year based at CERN.

Contact:

Letters of Reference should be sent to: p.soler@physics.gla.ac.uk