TY  - GEN
A1  - Kolpin, Michael
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/23940/
ID  - heidok23940
N2  - The measurement of the differential branching fraction and an angular
analysis of the decay B s 0 ? ?? + ? ? is performed, using a dataset collected by the LHCb
experiment in proton-proton collisions in 2011 and 2012, corresponding to an integrated
luminosity of 3 fb ?1 . The results are presented as function of q 2 , the square of the dimuon
invariant mass. A full set of angular observables is extracted for the first time for this
decay mode, where all measured angular coefficients are consistent with Standard Model
expectations. For the range of 1 < q 2 < 6 GeV 2 /c 4 the branching fraction is found to be
more than 3 standard deviations below the Standard Model prediction, which is derived
using a combination of light-cone sum rules and lattice QCD calculations. This tension
is compatible with observations made by other measurements of electroweak penguin
decays mediated by b ? s + ? transitions in this q 2 region. Possible explanations are
theoretical models which predict new heavy degrees of freedom at the TeV scale, as well
as underestimated contributions from cc-loop corrections in the SM calculations.
An important aspect of the measurements of branching fractions is the determination of
the track reconstruction efficiency. It is determined from J/? ? ? + ? ? decays, where the
data-driven tag-and-probe technique is used. During LHC Run II this measurement is
performed in a ?quasi-online? approach, directly after the data has been recorded. For
the 2015 data-taking period of the LHCb experiment, the track reconstruction efficiency is
found to be (96.14 ± 0.03)%, where the uncertainty is statistical only.
Y1  - 2018///
TI  - Measurement of the differential branching fraction and angular analysis of the decay $B_s^0\to\phi\mu^+\mu^-$ and determination of the track reconstruction efficiencies at the LHCb experiment
AV  - public
ER  -