arXiv subjects

Babar Collaboration

Publications and source records attributed to Babar Collaboration.

2 recordsLinked to original sources

arXiv2015

Measurement of Angular Asymmetries in the Decays B->K*l+l-

We study the lepton forward-backward asymmetry AFB and the longitudinal K* polarization FL, as well as an observable P2 derived from them, in the rare decays B->K*l+l-, where l+l- is either e+e- or mu+mu-, using the full sample of 471 million BBbar events collected at the Upsilon(4S) resonance with the Babar detector at the PEP-II e+e- collider. We separately fit and report results for the B+->K*+l+l- and B0->K*0l+l- final states, as well as their combination B->K*l+l-, in five disjoint dilepton mass-squared bins. An angular analysis of B+->K*+l+l- decays is presented here for the first time.

hep-ex↗

arXiv2000

PIN Photodiodes for Radiation Monitoring and Protection in the BaBar Silicon Vertex Tracker

We discuss the design, implementation and performance of the radiation monitoring and protection system used by the Silicon Vertex Tracker (SVT) in the BaBar detector. Using 12 reverse-biased PIN photodiodes mounted around the beampipe near the IP, we are able to provide instantaneous radiation dose rates, absorbed dose integrals, and active protection that aborts the circulating beams in the PEP-II storage ring when radiation levels exceed user-defined thresholds. The system has reliably protected the SVT from excessive radiation damage and has also served as a key diagnostic tool in understanding radiation backgrounds at PEP-II.

hep-ex↗