# Physics at LHC 2012

4-9 June 2012
Life Sciences Centre, UBC
<strong><font color="#cc0000">Abstract submission has closed</font></strong>

## Measuring the b-jet tagging efficiency on c-jets containing D* mesons with ATLAS data

4 Jun 2012, 16:00
1h
West Atrium (Life Sciences Centre, UBC)

### West Atrium

#### Life Sciences Centre, UBC

University of British Columbia Vancouver, BC Canada
Poster Standard Model & Beyond

### Speaker

Andrea Ferretto Parodi (Sezione di Genova)

### Description

The identification of jets originating from b-quarks (b-tagging)is a crucial tool for the LHC physics program, both for precision measurements and in searches for new particles. One important ingredient when using b-tagging in physics analyses is the determination of the probability to mistakenly b-tag a jet originating from a c-quark (c-tag efficiency). The optimal sample for the measurement of the c-tag efficiency would be a clean sample of jets originating from c-quarks. The sample of jets associated to reconstructed $D^*$ mesons (through the decay chain $D^* \to D^0(K \pi \pi)$ is quite close to this ideal case since most $D^*$ mesons originate from c-quark hadronization. The c-tag efficiency has been measured by comparing the reduction in the yield of $D^*$ mesons before and after the b-tagging requirement of the associated jet. The contamination from $D^*$ mesons that originate from b-hadron decays has been taken into account using a fit to the $D^0$ pseudo-proper time distribution.

### <strong>Collaboration Name</strong><br /><font color="#000099">Please enter the name of<br />the collaboration or group<br />using the acronym, as in:<br /><font color="#ff0000">ABC Collaboration</font>

ATLAS Collaboration