The first observation of the decays Λ$^0_b$ → $χ$c1$pK$- and Λ$^0_b$ → $χ$c2$pK$- is reported using a data sample corresponding to an integrated luminosity of 3.0 fb-1, collected by the LHCb ...experiment in $pp$ collisions at center-of-mass energies of 7 and 8 TeV. The following ratios of branching fractions are measured: $$\frac{\mathscr{B}(Λ^0_b→Χ_{c1}pK^-)}{\mathscr{B}(Λ^0_b→J/ψpK^-)}=0.242 ± 0.014 ± 0.013 ± 0.009$$ $$\frac{\mathscr{B}(Λ^0_b→Χ_{c2}pK^-)}{\mathscr{B}(Λ^0_b→J/ψpK^-)}= 0.248 ± 0.020 ± 0.014 ± 0.009$$ $$\frac{\mathscr{B}(Λ^0_b→Χ_{c2}pK^-)}{\mathscr{B}(Λ^0_b→Χ_{c1}pK^-)}= 1.02 ± 0.10 ± 0.02 ± 0.05$$ where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty on the branching fractions of the $Χ_{c1}$ → $Jψγ$ and $Χ_{c2}$ → $Jψγ$ decays. Using both decay modes, the mass of the Λ$^0_b$ baryon is also measured to be $m$Λ$^0_b$ = 5619.44 ± 0.28 ± 0.26 MeV/$c$2, where the first and second uncertainties are statistical and systematic, respectively.
The production of the
η
c
(
1
S
)
state in proton-proton collisions is probed via its decay to the
p
p
¯
final state with the LHCb detector, in the rapidity range
2.0
<
y
<
4.5
and in the meson ...transverse-momentum range
p
T
>
6.5
GeV
/
c
. The cross-section for prompt production of
η
c
(
1
S
)
mesons relative to the prompt
J
/
ψ
cross-section is measured, for the first time, to be
σ
η
c
(
1
S
)
/
σ
J
/
ψ
=
1.74
±
0.29
±
0.28
±
0
.
18
B
at a centre-of-mass energy
s
=
7
TeV
using data corresponding to an integrated luminosity of 0.7 fb
-
1
, and
σ
η
c
(
1
S
)
/
σ
J
/
ψ
=
1.60
±
0.29
±
0.25
±
0
.
17
B
at
s
=
8
TeV
using 2.0 fb
-
1
. The uncertainties quoted are, in order, statistical, systematic, and that on the ratio of branching fractions of the
η
c
(
1
S
)
and
J
/
ψ
decays to the
p
p
¯
final state. In addition, the inclusive branching fraction of
b
-hadron decays into
η
c
(
1
S
)
mesons is measured, for the first time, to be
B
(
b
→
η
c
X
)
=
(
4.88
±
0.64
±
0.29
±
0
.
67
B
)
×
10
-
3
, where the third uncertainty includes also the uncertainty on the
J
/
ψ
inclusive branching fraction from
b
-hadron decays. The difference between the
J
/
ψ
and
η
c
(
1
S
)
meson masses is determined to be
114.7
±
1.5
±
0.1
MeV
/
c
2
.
•MEG data from 7 TS patients with surgically confirmed epileptogenic zone location.•Interictally “MEG-silent” tubers were not epileptogenic.•Interictally “EEG/MEG-active” tuber not necessarily ...coincided with EZ.•Ictal MEG helped to select the EZ among several interictally “MEG-active” tubers.•Combination of ictal/interictal MEG may improve the non-invasive evaluation of EZ.
Drug resistant epilepsy (DRE) is common in patients with tuberous sclerosis (TS). Interictal MEG has been shown as a valuable instrument in the presurgical workup. The goal of our study was to evaluate the role of ictal MEG in epileptogenic tuber selection, especially in patients with multiple irritative zones.
The clinical and MEG data of 23 patients with TS and DRE from two medical/research centers were reviewed. Seven pediatric patients, who had seizures during MEG recording and underwent resection or disconnection surgery, were included into the study. Cortical sources of ictal and interictal epileptiform MEG discharges were compared with epileptogenic zone location in six patients with favorable surgery outcome.
In patients who improved substantially after surgery all resected and several other tubers demonstrated epileptiform activity on interictal MEG. Ictal MEG provided crucial information about lobar location of the seizure onset zone (SOZ) in two cases, and in the other four it confirmed the SOZ location derived from the interictal data. In one case, ictal MEG findings were unreliable. In one patient, who did not benefit from surgical treatment, the resected tubers did not overlap with interictal and ictal MEG sources.
The combination of interictal and ictal MEG is a valuable tool for identification of the epileptogenic tuber/tubers in presurgical work-up in patients with TS.
A
bstract
Measurements are reported of the central exclusive production of
J/ψ
and
ψ
(2
S
) mesons in
pp
collisions at a centre-of-mass energy of 13 TeV. Backgrounds are significantly reduced ...compared to previous measurements made at lower energies through the use of new forward shower counters. The products of the cross-sections and the branching fractions for the decays to dimuons, where both muons are within the pseudorapidity range 2
.
0
< η <
4
.
5, are measured to be
σ
J
/
ψ
→
μ
+
μ
−
=
435
±
18
±
11
±
17
p
b
σ
ψ
2
S
→
μ
+
μ
−
=
11.1
±
1.1
±
0.3
±
0.4
p
b
.
The first uncertainties are statistical, the second are systematic, and the third are due to the luminosity determination. The cross-sections are also measured differentially for meson rapidities between 2.0 and 4.5. Good agreement is observed with theoretical predictions. Photoproduction cross-sections are derived and compared to previous experiments, and a deviation from a pure power-law extrapolation of lower energy data is observed.
Study of J/ψ Production in Jets Andrews, J E; Appleby, R B; Artamonov, A ...
Physical review letters,
05/2017, Letnik:
118, Številka:
19
Journal Article
Recenzirano
Odprti dostop
The production of J/ψ mesons in jets is studied in the forward region of proton-proton collisions using data collected with the LHCb detector at a center-of-mass energy of 13 TeV. The fraction of the ...jet transverse momentum carried by the J/ψ meson, z(J/ψ)≡p_{T}(J/ψ)/p_{T}(jet), is measured using jets with p_{T}(jet)>20 GeV in the pseudorapidity range 2.5<η(jet)<4.0. The observed z(J/ψ) distribution for J/ψ mesons produced in b-hadron decays is consistent with expectations. However, the results for prompt J/ψ production do not agree with predictions based on fixed-order nonrelativistic QCD. This is the first measurement of the p_{T} fraction carried by prompt J/ψ mesons in jets at any experiment.
The ratio of the B-s(0) and B-0 fragmentation fractions, f(s)/f(d), in proton-proton collisions at the LHC, is obtained as a function of B-meson transverse momentum and collision center-of-mass ...energy from the combined analysis of different B-decay channels measured by the LHCb experiment. The results are described by a linear function of the meson transverse momentum or with a function inspired by Tsallis statistics. Precise measurements of the branching fractions of the B-s(0) -> J/psi phi and B-s(0)-> D-s(-)pi(+) decays are performed, reducing their uncertainty by about a factor of 2 with respect to previous world averages. Numerous B-s(0) decay branching fractions, measured at the LHCb experiment, are also updated using the new values of f(s)/f(d) and branching fractions of normalization channels. These results reduce a major source of systematic uncertainty in several searches for new physics performed through measurements of B-s(0) branching fractions.
We present measurements of partial branching fractions of inclusive semileptonic B → Xuℓ+ νℓ decays using the full Belle dataset of 711 fb−1 of integrated luminosity at the Υ(4S) resonance and for ℓ ...= e, μ. Inclusive semileptonic B → Xuℓ+ νℓ decays are Cabibbo-Kobayashi-Maskawa (CKM) suppressed and measurements are complicated by the large background from CKM favored B → Xcℓ+ νℓ transitions, which have a similar signature. Using machine learning techniques, we reduce this and other backgrounds effectively, while retaining access to a large fraction of the B → Xuℓ+νℓ phase space and high signal efficiency. We measure partial branching fractions in three phase-space regions covering about 31% to 86% of the accessible B → Xuℓ+νℓ phase space. The most inclusive measurement corresponds to the phase space with lepton energies of EBℓ > 1 GeV, and we obtain ΔB ( B → Xuℓ+νℓ) = (1.59 ± 0.07 ± 0.16) × 10−3 from a two-dimensional fit of the hadronic mass spectrum and the four-momentum-transfer squared distribution, with the uncertainties denoting the statistical and systematic error. We find |Vub| = (4.10 ± 0.09 ± 0.22 ± 0.15) × 10−3 from an average of four calculations for the partial decay rate with the third uncertainty denoting the average theory error. This value is higher but compatible with the determination from exclusive semileptonic decays within 1.3 standard deviations. In addition, we report charmless inclusive partial branching fractions separately for B + and B 0 mesons as well as for electron and muon final states. No isospin breaking or lepton flavor universality violating effects are observed.
The ratio of the B0s and B+ fragmentation fractions fs and fu is studied with B0s → J/ψ ϕ and B+ → J/ψK+ decays using data collected by the LHCb experiment in proton-proton collisions at 7, 8, and 13 ...TeV center-of-mass energies. The analysis is performed in bins of B -meson momentum, longitudinal momentum, transverse momentum, pseudorapidity, and rapidity. The fragmentation-fraction ratio fs/fu is observed to depend on the B -meson transverse momentum with a significance of 6.0σ . This dependency is driven by the 13 TeV sample (8.7σ), while the results for the other collision energies are not significant when considered separately. Furthermore, the results show a 4.8σ evidence for an increase of fs/fu as a function of collision energy.
In the past decade significant attention has been given to the development of tools that attempt to measure the vulnerability, risk or resilience of communities to disasters. Particular attention has ...been given to the development of composite indices to quantify these concepts mirroring their deployment in other fields such as sustainable development. Whilst some authors have published reviews of disaster vulnerability, risk and resilience composite indicator methodologies, these have been of a limited nature. This article describes action research that examines all kinds of natural and industrial disasters and their influence on the world economy. It also gives a detailed description of the structures dealing with emergency situations in some African countries and proves that these countries lack educational institutions which would teach people to manage the emergency situations and coordinate their activities with international organizations for providing more efficient assistance to people affected by the disaster.
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