Initial analysis towards a measurement of the branching fractions B [right arrow] [rho][gamma] and B [right arrow] [omega][gamma]

• Main Author: Bright, Molly (Molly Gallogly)
• Other Authors: Gabriella Sciolla.
• Format: Others
• Language: English
• Published: Massachusetts Institute of Technology 2007
• Subjects: Physics.
• Online Access: http://hdl.handle.net/1721.1/36133

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics, 2006. === In title on t.p., "[right arrow]" is represented by the symbol, and "[rho]", "[gamma]" and "[omega]" are lower case Greek letters. === Includes bibliographical references (p. 63). === The Standard Model of particle physics predicts the existence of the "Unitary Triangle," which graphically relates the matrix elements of the Cabbibo Kobayashi Maskawa matrix and describes the strength of transformations from one quark to another. By measuring the ratio [Beta](B [right arrow] [rho]/[omega][gamma]) / [Beta](B [right arrow] K*[gamma]) we can measure a side length of this triangle and use the result to test the Standard Model, and perhaps illuminate new physics. In this thesis, a new set of cuts on variables measured by the BABAR detector is optimized to obtain high levels of efficiency and significance in separating the rare [rho][gamma] or [omega][gamma] signal events from the high levels of continuum background. Neural nets that can consider correlations between variables have also been implemented to suppress the continuum. Preliminary results using Monte Carlo are discussed. Final values using runs 1 through 5 of the BaBar experimental data will be published in summer 2006. === by Molly Bright. === S.B.