The first simultaneous test of muon-electron universality using B+→K+ℓ+ℓ− and B0→K*0ℓ+ℓ− decays is performed, in two ranges of the dilepton invariant-mass squared, q2. The analysis uses beauty mesons ...produced in proton-proton collisions collected with the LHCb detector between 2011 and 2018, corresponding to an integrated luminosity of 9 fb−1. Each of the four lepton universality measurements reported is either the first in the given q2 interval or supersedes previous LHCb measurements. The results are compatible with the predictions of the Standard Model.
The article presents a description of the ISNP/GNEIS testing facility with a neutron spectrum that reproduces the spectrum of atmospheric neutron radiation. The facility was developed at the ...Petersburg Nuclear Physics Institute (PNPI) of the National Research Center Kurchatov Institute in collaboration with the Institute of Space Device Engineering, a branch of JSC (Joint Stock Company) United Rocket and Space Corporation. The spallation neutron source of the facility is based on the 1-GeV SC-1000 proton synchrocyclotron at the PNPI. The internal neutron-production lead target produces 10-ns pulses of neutrons with a repetition rate of 45–50 Hz and an average neutron intensity of 3 × 10
14
n/s (in the 4σ solid angle). In the irradiation area located at a distance of 36 m from the neutron source, a high-quality collimated neutron beam with a broad energy spectrum of 1–1000 MeV and a neutron flux of 4 × 10
5
n/(cm
2
s) allows conducting accelerated single-event soft error testing of electronic components. In the course of the irradiation, the neutron energy spectrum and intensity and the spatial profile of the beam are controlled using a fission ionization chamber (beam monitor) and a position-sensitive multiwire proportional counter (beam profile meter). The data acquisition system of the ISNP/GNEIS facility utilizes 250 MS/s 12 bit CAEN waveform digitizers for the processing of signals from the monitor and profile meter by the neutron time-of-flight technique. In the report, parameters of the ISNP/GNEIS testing facility are discussed in comparison with analogous world-class facilities, as well as requirements and recommendations of the standards used in this field.
To characterize a group of patients with follicular lymphoma (FL) with leukemization and to evaluate the efficiency of different therapy options (R-CHOP/R-FMC/high-dose chemotherapy (HDCT)).
18 ...(7.2%) out of 250 patients diagnosed with FL, who were examined and treated at the National Research Center for Hematology, Ministry of Health of the Russian Federation, were found to have leukemic FL (tumor cells in the peripheral blood smears were detected by cytology and flow cytofluorometry. Eight of the 18 patients had extranodal foci of involvement: lung, stomach, spleen, lumbar muscles, upper jaw, and vertebrae. Bone marrow was involved in 17 of the 18 patients. Tumor biopsy specimens displayed a morphological pattern of indolent FL in the majority of patients (10 of the 18 patients had cytological grade 1-2 tumors and 14 patients had a nodular or nodular-diffuse tumor growth pattern). The patients underwent R-CHOP/R-FMC) or HDCT cycles as first-line therapy, followed by autologous stem cell transplantation (auto-SCT).
The median follow-up was 66 months (range 12-217 months). The 5-year overall survival (OS) and progression-free survival (PFS) rates were 70% (10% SEM) and 35% (15% SEM), respectively. The median OS was not reached; the median PFS was 3 years.
Leukemic FL is characterized by low OS and PFS rates. The most effective chemotherapy regimens were R-CHOP, followed by HDCT and auto-SCT in first remission or R-FMC. These cycles can to a greater extent achieve a complete eradication of the bone marrow tumor clone. Due to the relapsing course of FL and the aggressiveness of leukemic FL, it is expedient to carry out auto-SCT in first remission.
A
bstract
A first search for the lepton-flavour violating decays
B
0
→
K
*0
τ
±
μ
∓
is presented. The analysis is performed using a sample of proton-proton collision data, collected with the LHCb ...detector at centre-of-mass energies of 7, 8 and 13 TeV between 2011 and 2018, corresponding to an integrated luminosity of 9 fb
−
1
. No significant signal is observed, and upper limits on the branching fractions are determined to be
B
B
0
→
K
∗
0
τ
+
μ
−
<
1.0
1.2
×
10
−
5
and
B
B
0
→
K
∗
0
τ
−
μ
+
<
8.2
9.8
×
10
−
6
at the 90% (95%) confidence level.
To evaluate the efficiency and toxicity of the intensive Burkitt's lymphoma (BL) therapy protocol BL-M-04.
A total of 70 patients diagnosed with BL, including 45 men and 25 women whose age was 15 to ...62 years (median age 31 years), were followed up in 2003 to 2014. Stage I (according to S. Murphy) was diagnosed in 4 (5.7%) patients; II in 9 (12.9%), III in 25 (35.7%), IV in 11 (15.7%), and Burkitt's leukemia in 21 (30%). There were tumor involvements of the bone marrow and central nervous system in 23 (32.9%) and 15 (21.4%) patients, respectively. B symptoms were detected in 56 (80%) patients; enhanced lactate dehydrogenase (LDH) activity was found in 50 (78.1%) out of 64 patients; moreover, in 34 (56.2%) out of 64 patients, LDH activity was more than twice as high as the reference values. The median LDH activity was 2398 (238-20,300) U/I. Acute renal failure at disease onset was identified in 17 (24.2%) patients; chemotherapy was initiated in 8 patients during renal replacement therapy. The treatment was performed using the BL-M-04±R protocol (4 successive blocks of A-C-A-C±R). Six blocks of A-C-A-C-A-C with rituximab has been carried out in patients with bone marrow involvement since 2011.
Sixty-two (89%) patients achieved complete remission. At this time, 6 patients died from therapy complications during remission induction; 2 patients were observed to have disease progression; 3 developed disease recurrence (2 patients had early recurrence; 1 patient developed recurrence 2 years after treatment). Five-year overall survival (OS) was 85%; 5-year relapse-free survival (RFS) was 95%. The Cox multivariate regression analysis revealed that Burkitt's leukemia and bone marrow involvement were independent factors that influenced OS and RFS. The poor somatic status (3-4 ECOC scores versus 0-2 scores) proved to be statistically significant for OS rather than RFS.
Despite the optimistic results obtained by our study group, there is a need to further improve BL treatment protocols and to elaborate novel approaches to therapy particularly for older patients and patients with Burkitt's leukemia.
A measurement of
D
0
meson production by the LHCb experiment in its fixed-target configuration is presented. The production of
D
0
mesons is studied with a beam of 2.5
Te
V
protons colliding on a ...gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of
s
NN
=
68.5
Ge
V
. The sum of the
D
0
and
D
¯
0
production cross-section in
p
Ne
collisions in the centre-of-mass rapidity range
y
⋆
∈
-
2.29
,
0
is found to be
σ
D
0
y
⋆
∈
-
2.29
,
0
=
48.2
±
0.3
±
4.5
μ
b
/
nucleon
where the first uncertainty is statistical and the second is systematic. The
D
0
-
D
¯
0
production asymmetry is also evaluated and suggests a trend towards negative values at large negative
y
⋆
. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1
%
intrinsic charm and 10
%
recombination contributions better describe the data than the other models considered.
A
bstract
The production of prompt
D
+
and
D
s
+
mesons is studied in proton-lead collisions at a centre-of-mass energy of
s
NN
= 5
.
02 TeV. The data sample corresponding to an integrated luminosity ...of (1
.
58 ± 0
.
02)nb
−
1
is collected by the LHCb experiment at the LHC. The differential production cross-sections are measured using
D
+
and
D
s
+
candidates with transverse momentum in the range of 0
< p
T
<
14 GeV
/c
and rapidities in the ranges of 1
.
5
< y
∗
<
4
.
0 and –5
.
0
< y
∗
<
–2
.
5 in the nucleon-nucleon centre-of-mass system. For both particles, the nuclear modification factor and the forward-backward production ratio are determined. These results are compared with theoretical models that include initial-state nuclear effects. In addition, measurements of the cross-section ratios between
D
+
,
D
s
+
and
D
0
mesons are presented, providing a baseline for studying the charm hadronization in lead-lead collisions at LHC energies.
A
bstract
Four decay modes of the
B
c
+
meson into a
J/ψ
meson and multiple charged kaons or pions are studied using proton-proton collision data, collected with the LHCb detector at centre-of-mass ...energies of 7, 8, and 13 TeV and corresponding to an integrated luminosity of 9 fb
−
1
. The decay
B
c
+
→ J/ψK
+
K
−
π
+
π
+
π
−
is observed for the first time, and evidence for the
B
c
+
→ J/ψ
4
π
+
3
π
−
decay is found. The decay
B
c
+
→ J/ψ
3
π
+
2
π
−
is observed and the previous observation of the
B
c
+
→ ψ
(2
S
)
π
+
π
+
π
−
decay is confirmed using the
ψ
(2
S
) →
J/ψπ
+
π
−
decay mode. Ratios of the branching fractions of these four
B
c
+
decay channels are measured.
A
bstract
A search for the lepton-flavour violating decays
B
0
→
K
*0
μ
±
e
∓
and
B
s
0
→ ϕμ
±
e
∓
is presented, using proton-proton collision data collected by the LHCb detector at the LHC, ...corresponding to an integrated luminosity of 9 fb
−
1
. No significant signals are observed and upper limits of
B
B
0
→
K
∗
0
μ
+
e
−
<
5.7
×
10
−
9
6.9
×
10
−
9
,
B
B
0
→
K
∗
0
μ
−
e
+
<
6.8
×
10
−
9
7.9
×
10
−
9
,
B
B
0
→
K
∗
0
μ
±
e
∓
<
10.1
×
10
−
9
11.7
×
10
−
9
,
B
B
s
0
→
ϕ
μ
±
e
∓
<
16.0
×
10
−
9
19.8
×
10
−
9
are set at 90% (95%) confidence level. These results constitute the world’s most stringent limits to date, with the limit on the decay
B
s
0
→ ϕμ
±
e
∓
the first being set. In addition, limits are reported for scalar and left-handed lepton-flavour violating New Physics scenarios.
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