We present a solution made out of Components Out of Shelf (COTS) for the analog processing of the signal of the LHCb calorimeters in the framework of the foreseen upgrade of the detector. The present ...proposal is based on the current functional solution, yet, to meet the stringent noise requirements, a number of modifications are proposed. Preliminary results on the prototype boards show promising results.
A
bstract
The isospin asymmetries of
B
→
K
(∗)
μ
+
μ
−
decays and the partial branching fractions of
B
0
→
K
0
μ
+
μ
−
and
B
+
→
K
∗+
μ
+
μ
−
are measured as a function of the di-muon mass ...squared
q
2
using an integrated luminosity of 1.0 fb
−1
collected with the LHCb detector. The
B
→
Kμ
+
μ
−
isospin asymmetry integrated over
q
2
is negative, deviating from zero with over 4 σ significance. The
B
→
K
∗
μ
+
μ
−
decay measurements are consistent with the Standard Model prediction of negligible isospin asymmetry. The observation of the decay
B
0
→
K
S
μ
+
μ
−
is reported with 5.7 σ significance. Assuming that the branching fraction of
B
0
→
K
0
μ
+
μ
−
is twice that of
B
0
→
K
S
μ
+
μ
−
, the branching fractions of
B
0
→
K
0
μ
+
μ
−
and
B
→
K
∗+
μ
+
μ
−
are found to be (0
.
31
−0.06
) × 10
−6
and (1
.
16 ± 0
.
19) × 10
−6
, respectively.
A
bstract
A search for the rare two-body charmless baryonic decay
B
+
→
p
Λ
¯
is performed with
pp
collision data, corresponding to an integrated luminosity of 3 fb
−1
, collected by the LHCb ...experiment at centre-of-mass energies of 7 and 8 TeV. An excess of
B
+
→
p
Λ
¯
candidates with respect to background expectations is seen with a statistical significance of 4.1 standard deviations, and constitutes the first evidence for this decay. The branching fraction, measured using the
B
+
→
K
S
0
π
+
decay for normalisation, is
ℬ
B
+
→
p
Λ
¯
=
2
.
4
−
0.8
+
1.0
±
0.3
×
1
0
−
7
,
where the first uncertainty is statistical and the second systematic.
First observation of the decay B+ → π+μ+μ Adametz, A.; Adrover, C.; Ajaltouni, Z. ...
The journal of high energy physics,
12/2012, Letnik:
2012, Številka:
12
Journal Article
Recenzirano
Odprti dostop
A
bstract
A discovery of the rare decay
B
+
→
π
+
μ
+
μ
−
is presented. This decay is observed for the first time, with 5.2
σ
significance. The observation is made using
pp
collision data, ...corresponding to an integrated luminosity of 1.0 fb
−1
, collected with the LHCb detector. The measured branching fraction is (2.3 ± 0.6 (stat.) ± 0.1 (syst.))×10
−8
, and the ratio of the
B
+
→
π
+
μ
+
μ
−
and
B
+
→
K
+
μ
+
μ
−
branching fractions is measured to be 0.053 ± 0.014 (stat.) ± 0.001 (syst.).
A
bstract
A study of mixing and indirect CP violation in
D
0
mesons through the determination of the parameters
y
CP
and
A
Γ
is presented. The parameter
y
CP
is the deviation from unity of the ratio ...of effective lifetimes measured in
D
0
decays to the CP eigenstate
K
+
K
−
with respect to decays to the Cabibbo favoured mode
K
−
π
+
. The result measured using data collected by LHCb in 2010, corresponding to an integrated luminosity of 29 pb
−1
, is
y
CP
= (5
.
5 ± 6
.
3
stat
± 4
.
1
syst
) × 10
−3
. The parameter
A
Γ
is the asymmetry of effective lifetimes measured in decays of
D
0
and
mesons to
K
+
K
−
. The result is
A
Γ
= (−5
.
9 ± 5
.
9
stat
± 2
.
1
syst
) × 10
−3
. A data-driven technique is used to correct for lifetime-biasing effects.
The calibration and performance of the LHCb Calorimeter system in Run 1 and 2 at the LHC are described. After a brief description of the sub-detectors and of their role in the trigger, the ...calibration methods used for each part of the system are reviewed. The changes which occurred with the increase of beam energy in Run 2 are explained. The performances of the calorimetry for \(\gamma\) and \(\pi^0\) are detailed. A few results from collisions recorded at \(\sqrt {s}\) = 7, 8 and 13 TeV are shown.
A
bstract
The production of χ
b
(1
P
) mesons in
pp
collisions at a centre-of-mass energy of 7 TeV is studied using 32 pb
−1
of data collected with the LHCb detector. The χ
b
(1
P
) mesons are ...reconstructed in the decay mode χ
b
(1
P
) →
Υ
(1
S
)γ →
μ
+
μ
−
γ. The fraction of
Υ
(1
S
) originating from χ
b
(1
P
) decays in the
Υ
(1
S
) transverse momentum range 6
<
p
T
Υ
(1
S
)
<
15 GeV
/c
and rapidity range 2
.
0
< y
Υ (1S)
<
4
.
5 is measured to be
, where the first uncertainty is statistical, the second is systematic and the last gives the range of the result due to the unknown
Υ
(1
S
) and χ
b
(1
P
) polarizations.
A
bstract
A study of
and
D
0
K
+
final states is performed in a sample of 1.0 fb
−1
of
pp
collision data collected at a centre-of-mass energy of
with the LHCb detector. We confirm the existence of ...the
and
excited states and measure their masses and widths to be
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