Particle Physics Division

Localisation

The experiment was located at Stanford Linear Accelerator Center (SLAC) at Stanford University in the United States, using the PEP-II electron-positron collider.

Initiated in November 1993, the experiment took daata between May 1999 and April 2008.

Contribution from Irfu (ex-Dapnia)

The contributions

Dapnia played a major role in the construction and running of the DIRC detector (1995-1998). The DIRC was the main detector for particle identification in BABAR. This novel device prooved to be robust and performant.

In particular, Dapnia was responsible for:
- the mechanical structure of the Cerenkov light detector;
- the 11000 photomultiplicator tubes;
- the magnetic shielding;
- the calibration system;
- the reconstruction code;
- the alignement procedure.

Dapnia also played a very active role in data analysis:
- measure of the alpha angle of the unitarity triangle (with the B decays to rho pi and rho rho);
- measure of sin(2beta+gamma) (B→D* pi mode);
- study of the B→K* rho modes;
- study of the eta_c meson, measure of the beta angle;
- measure of the Vub parameter;
- study of CP, T, and CPT violation in dilepton events.

Scientific responsabilities

Physicists from Dapnia have had important positions in the collaboration:
- physics analysis coordinator (2000-2001) ;
- chair of the speakers bureau (1997-1998) ;
- conveners of several physics analysis groups (dileptons, inclusive hadronic B meson decays, time dependent analyses of B meson decays to charm);
- co-system manager of the DIRC detector (1995-1998 and 2003-2007)

- data quality manager (2001-2002);

- member of the executive board (2006-2009);

- president of the membership committee (2010-2014).

Scope of the experiment

The BABAR experiment has been one of the major experiment in High Energy Physics from 1999 to 2008. Dapnia and SPP have been heavily involved with a maximum of 14 physicists at the same time.