Threshold effects in the decay of heavy b ′ and t ′ quarks
Journal
Physical Review D - Particles, Fields, Gravitation and Cosmology
Journal Volume
84
Journal Issue
1
Date Issued
2011
Author(s)
Abstract
A sequential fourth generation is still viable, but the t′ and b′ quarks are constrained not to be too far apart in mass. The t′→bW and b′→tW decay channels are still being pursued at the Tevatron, which will soon be surpassed by the LHC. We use a convolution method with up to five-body final states to study t′ and b′ decays. We show how the two decay branches for mb′ below the tW threshold, b ′→tW* and t*W, merge with b′→tW above the threshold. We then consider the heavy-to-heavy transitions b′→t′( *)W(*) (or t′→b ′(*)W(*), as they are not suppressed by quark mixing. We find that, because of the threshold sensitivity of the branching fraction of t′→b′W * (or b′→t′W *), it is possible to measure the strength of the CKM mixing element Vt′b (or Vtb′), especially when it is rather small. We urge experimenters to pursue and separate the t ′→b′W* (or b ′→t′W*) decay in their search programs. © 2011 American Physical Society.
Type
journal article