Physics Topics

At this moment (2011-2014), the physics topics under investigation by members of our group include:

b-baryon studies

Given the copious amount of the charm and beauty hadrons recorded by LHCb, studies of the production and the spectroscopy of the heavy quark hadrons are bound to provide interesting results. Good candidates for such kind of studies are the b-baryons, as these hadrons could not be produced at the b-factories (BaBar, Belle, etc.) and the measurements reported by the Tevatron experiments were based on very low statistics. The first results of measurements of the b-baryon lifetimes [link] and masses [link] are already published and more results will follow in the near future.

In our group, work is in progress to measure the Λb cross-section using the decay Λb -> J/Ψ Λ.

B-mesons radiative decays

The radiative transitions b -> s γ and b -> d γ are flavor changing processes, described by penguin diagrams, very sensitive to New Physics (NP). Therefore, the B-meson decay modes Bd -> K* γ and Bs -> Φ γ are good candidates for the search of the NP effects, since in these channels the NP contribution to the decay amplitude might be comparable to the Standard Model (SM) one. Precise measurements of such radiative decays branching ratios, of their asymmetries, or of their angular distributions is then expected to reveal NP effects.

Members of our group contributed to the LHCb preliminary result (study of the background composition using Monte Carlo (MC) simulation and proper-time acceptance studies) on the radiative decays of the B mesons (see here) and will follow this work until the publication.

Soft QCD Studies & MC tunes for LHCb

The rules of fragmentation/hadronization are not fully understood, only phenomenological models, implemented in Monte Carlo generators (e.g. PYTHIA), are available. The agreement between models is broken at LHC, due to different energy extrapolations.

LHCb is the only LHC detector fully instrumented in the forward region where the models disagree the most, also extrapolation in rapidity, thus the interest for soft-QCD measurements at LHCb. Starting from the results already published by LHCb [link] for the production of strange particles, at present our group is involved in studies of strange particle production ratios and cross-sections (K0s, Λ, Ξ, Ω).

Members of our group implemented a series of existing tunes for PYTHIA6 in Gauss (the Monte Carlo simulation package in the LHCb software framework). This work was done in preparation of producing LHCb specific tunes for PYTHIA8 based on the new measurements.

In the context of the service tasks which are the responsibility of our group, our group plans to use the RIVET/Professor validation software in future tuning studies for MC generators implemented in the LHCb software framework.