First Year of BABAR/PEP-II - Harvard University Laboratory for ...
First Year of BABAR/PEP-II - Harvard University Laboratory for ...
First Year of BABAR/PEP-II - Harvard University Laboratory for ...
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Experimental Challenges<br />
Exclusive reconstruction <strong>of</strong> CP eigenstates.<br />
◆ Low branching ratios.<br />
Br( B 0 → J/ψK S<br />
) ⋅ Br( J/ψ → l + l − ) ∼ 5 × 10 – 5 ,<br />
Br( B 0 → φK S<br />
) ⋅ Br( φ → K + K − ) ∼ 5 × 10 – 6 ,<br />
Br( B 0 → D∗ + D∗ −<br />
) ⋅ Br( D∗ + → D 0 π + ) 2 ⋅ Br( D 0 → K − π + ⁄ K − π + π 0 ) 2<br />
∼ 1.4 × 10 – 5 .<br />
→ High statistics, high efficiency.<br />
◆ High multiplicity.<br />
→ Good detector hermeticity.<br />
e.g.: B 0 → D + D - K - π + π -<br />
◆ Combinatorial Background.<br />
K 0 π + π 0<br />
→ Good p T resolution. (Multiple scattering)<br />
→ Particle identification.<br />
→ Continuum suppression. (Γ bb /Γ qq ~ 1/3 at ϒ 4S .)<br />
<strong>First</strong> <strong>Year</strong> <strong>of</strong> BaBar/<strong>PEP</strong>-<strong>II</strong> Masahiro Morii SLAC
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