BaBar Experiment :: Chemistry Science Scientific Essays

BaBar ExperimentAbstract I investigated the L = 1 mesons D*2(2460)0 and D1(2420)0 using data gathered by the BaBar detector at Pep-II. The change integrity process of these particles is interesting because it could serve to confirm or deny reliable predictions made by HQET models. Thus far, the data gathered rougly conforms with measurements made by the CLEO and ARGUS collaborations. The data is still preliminary, however, and as such this paper should be considered merely a summary of the work done thus far. 1 Introduction1.1 The BaBar experimentThe BaBar detector at Pep-II was designed to study B mesons produced in asymmetric e+e- collisions. Asymmetric refers to the fact that the colliding electrons and positrons have various energies. This gives the resulting particles momentum in the laboratory reference frame, allowing their lifetimes to be measured all the same if they carry away most of the collision energy. In the current flush at Pep-II, electrons ar stored in one ring at 9 GeV and positrons in the other at 3.1 GeV. This sets the collision energy right at the T(4S) resonance, a short-lived combination of a bottom quark and its antiquark. This tumbles preferentially into a pair of mesons B and Bhence the name of the detector.Mesons are short-lived systems made up of a quark and an anti-quark Bs are mesons in which one quark is a bottom (or an anti-bottom) and the other is a agility quark (up, down, strange, or their corresponding antiquarks). The BaBar detector is optimized to measure the decay process of these Bs as precisely as possible. It is hoped that differences between the B and the B decay processes will be uncovered and measured, which will lead to a better understanding of CP symmetry violation.CP violation describes an event that breaks the so-called mien Parity symmetry. For a time, it was believed that if matter and antimatter were interchanged (hence, Charge) and if right and left were reversed (Parity), systems would expec t in an identical manner. This symmetry has since been found to be broken in certain kaon decays, and it is suspected that further violations will be notice in B decays. Note that if time is reversed as soundly as charge and parity, then the system will behave in an indentical manner this is known as CPT symmetry, and is required for Lorentz transformations. It is hoped that learning more nearly events that violate the broken CP symmetry will shed some light on the relative scarcity of antimatter in the universe.