JHEP 05 (2022) 038 The $\it{\Xi_{cc}^{++}\to \Xi_{c}^{'+}\pi^{+}}$ decay is observed using
proton-proton collisions collected by the LHCb experiment at a centre-of-mass
energy of $13\mathrm{\,Te\kern ...-0.1em V}$, corresponding to an integrated
luminosity of $5.4\,\mathrm{fb}^{-1}$. The $\it{\Xi_{cc}^{++}\to
\Xi_{c}^{'+}\pi^{+}}$ decay is reconstructed partially, where the photon from
the $\it{\Xi_{c}^{'+} \to \Xi_{c}^{+}\gamma}$ decay is not reconstructed and
the $pK^-\pi^+$ final state of the $\it{\Xi_{c}^{+}}$ baryon is employed. The
$\it{\Xi_{cc}^{++}\to \Xi_{c}^{'+}\pi^{+}}$ branching fraction relative to that
of the $\it{\Xi_{cc}^{++}\to \Xi_{c}^{+}\pi^{+}}$ decay is measured to be $1.41
\pm 0.17 \pm 0.10$, where the first uncertainty is statistical and the second
systematic.
JHEP 2022, 46 (2022) A study of $B^+ \rightarrow J/\psi \eta K^+$ decays, followed by $J/\psi
\rightarrow \mu^+ \mu^-$ and $\eta \rightarrow \gamma \gamma$, is performed
using a dataset collected ...with the LHCb detector in proton-proton collisions at
centre-of-mass energies of 7, 8 and 13 TeV, corresponding to an integrated
luminosity of 9 fb$^{-1}$. The $J/\psi\eta$ mass spectrum is investigated for
contributions from charmonia and charmonium-like states. Evidence is found for
the $B^+\rightarrow \left( \psi_2(3823) \rightarrow J/\psi \eta \right) K^+$
and $B^+\rightarrow \left( \psi(4040) \rightarrow J/\psi \eta \right) K^+$
decays with significance of 3.4 and 4.7~standard deviations, respectively. This
constitutes the~first~evidence for the $\psi_2(3823) \rightarrow J/\psi \eta$
decay.
The TORCH time-of-flight detector will provide particle identification between 2-10 GeV/c momentum over a flight distance of 10 m, and is designed for large-area coverage, up to 30 m^2. A 15 ps ...time-of-flight resolution per incident particle is anticipated by measuring the arrival times from Cherenkov photons produced in a synthetic fused silica radiator plate of 10 mm thickness. Customised Micro-Channel Plate Photomultiplier Tube (MCP-PMT) photon detectors of 53 x 53 mm^2 active area with a 64 x 64 granularity have been developed with industrial partners. Test-beam studies using both a small-scale TORCH demonstrator and a half-length TORCH module are presented. The desired timing resolution of 70 ps per single photon is close to being achieved.
JHEP05(2022)067 A search for the decay $B^0\to\phi\mu^+\mu^-$ is performed using
proton-proton collisions at centre-of-mass energies of 7, 8, and 13 TeV
collected by the LHCb experiment and ...corresponding to an integrated luminosity
of 9 fb$^{-1}$. No evidence for the $B^0\to \phi \mu^+ \mu^-$ decay is found
and an upper limit on the branching fraction, excluding the $\phi$ and
charmonium regions in the dimuon spectrum, of $4.4 \times 10^{-3}$ at a 90$\%$
credibility level, relative to that of the $B^0_s \to \phi \mu^+ \mu^-$ decay,
is established. Using the measured $B^0_s\to\phi\mu^+\mu^-$ branching fraction
and assuming a phase-space model, the absolute branching fraction of the decay
$B^0\to \phi \mu^+ \mu^-$ in the full $q^2$ range is determined to be less than
$3.2 \times 10^{-9}$ at a 90$\%$ credibility level.
TORCH is a time-of-flight detector designed to perform particle identification over the momentum range 2\(-\)10 GeV/c for a 10 m flight path. The detector exploits prompt Cherenkov light produced by ...charged particles traversing a quartz plate of 10 mm thickness. Photons are then trapped by total internal reflection and directed onto a detector plane instrumented with customised position-sensitive Micro-Channel Plate Photo-Multiplier Tube (MCP-PMT) detectors. A single-photon timing resolution of 70 ps is targeted to achieve the desired separation of pions and kaons, with an expectation of around 30 detected photons per track. Studies of the performance of a small-scale TORCH demonstrator with a radiator of dimensions 120 \(\times\) 350 \(\times\) 10 mm\(^3\) have been performed in two test-beam campaigns during November 2017 and June 2018. Single-photon time resolutions ranging from 104.3 ps to 114.8 ps and 83.8 ps to 112.7 ps have been achieved for MCP-PMTs with granularity 4 \(\times\) 64 and 8 \(\times\) 64 pixels, respectively. Photon yields are measured to be within \(\sim\)10% and \(\sim\)30% of simulation, respectively. Finally, the outlook for future work with planned improvements is presented.
PhysRevLett128,191803 (2022) The first observation of the semileptonic $b$-baryon decay $ \Lambda_b^0
\rightarrow \Lambda_c^+ \tau^-\overline{\nu}_{\tau}$, with a significance of
$6.1\,\sigma$, is ...reported using a data sample corresponding to 3 fb$^{-1}$ of
integrated luminosity, collected by the LHCb experiment at centre-of-mass
energies of 7 and 8 TeV at the LHC. The $\tau^-$ lepton is reconstructed in the
hadronic decay to three charged pions. The branching fraction
${\mathcal{B}}(\Lambda_b^0 \rightarrow \Lambda_c^+\tau^-\overline{\nu}_{\tau})
= (1.50 \pm 0.16\pm 0.25\pm 0.23)\%$ is obtained, where uncertainties are
statistical, systematic and from the external branching fraction of the
normalisation channel $\Lambda_b^0\rightarrow \Lambda_c^+\pi^-\pi^+\pi^-$. The
ratio of semileptonic branching fractions ${\mathcal{R}}( \Lambda_c^+)\equiv
{\mathcal{B}}( \Lambda_b^0 \rightarrow \Lambda_c^+
\tau^-\overline{\nu}_{\tau})/{\mathcal{B}}( \Lambda_b^0 \rightarrow \Lambda_c^+
\mu^-\overline{\nu}_{\mu})$ is derived to be $0.242 \pm 0.026 \pm 0.040\pm
0.059$, where the external branching fraction uncertainty from the channel
$\Lambda_b^0\rightarrow \Lambda_c^+\mu^-\overline{\nu}_{\mu}$ contributes to
the last term. This result is in agreement with the Standard Model prediction.
This study examined the pharmacokinetics (the time course and pattern of testosterone release) and pharmacodynamics (effects on accessory sex organ weights, and serum LH and FSH levels) of a ...biodegradable testosterone microsphere formulation in the male rat. Two hundred seventy-five 55-day-old, sexually mature male rats underwent surgical orchiectomy or sham surgery and were divided into five groups as follows, to receive placebo or testosterone microsphere systems designed to release 25, 75, or 225 micrograms/day testosterone: group I: intact age-matched controls, sham operated, placebo microspheres; group II: surgically orchiectomized, placebo microspheres; group III: surgically orchiectomized, 25 micrograms/day testosterone microspheres; group IV: surgically orchiectomized, 75 micrograms/day testosterone microspheres; and group V: surgically orchiectomized, 225 micrograms/day testosterone microspheres. Serum testosterone levels were fairly uniform from day 2 to 85 without any significant trend. After day 100, serum testosterone levels gradually fell into the castrate range by day 196. There was a dose-dependent increase in serum testosterone levels in groups III, IV, and V over those seen in group II (castrated rats, placebo treated). Prostate and seminal vesicle weights were significantly lower in castrated animals treated with placebo or the 25-micrograms/day testosterone microsphere system (group III). Mean prostate and seminal vesicle weights in groups IV and V were not significantly different from those in intact controls (group I) in the first 85 days. After day 85-100, seminal vesicle and prostate weights declined gradually in groups III, IV, and V, approaching castrate range by day 196.
Phys. Rev. D 105, 072005 (2022) The first observations of
$B^0\rightarrow\overline{D}^{*}(2007)^{0}K^{+}\pi^{-}$ and
$B_s^0\rightarrow\overline{D}^{*}(2007)^{0}K^{-}\pi^{+}$ decays are presented,
and ...their branching fractions relative to that of the
$B^0\rightarrow\overline{D}^{*}(2007)^{0}\pi^{+}\pi^{-}$ decay are reported.
These modes can potentially be used to investigate the spectroscopy of charm
and charm-strange resonances and to determine the angle $\gamma$ of the CKM
unitarity triangle. It is also important to understand them as a source of
potential background in determinations of $\gamma$ from $B^{+}\rightarrow
DK^{+}$ and $B^{0}\rightarrow DK^{+}\pi^{-}$ decays. The analysis is based on a
sample corresponding to an integrated luminosity of $5.4 ~\rm{fb}^{-1}$ of
proton--proton collision data at $13 ~\rm{TeV}$ centre-of-mass energy recorded
with the LHCb detector. The $\overline{D}^{*}(2007)^{0}$ mesons are fully
reconstructed in the $\overline{D}^{0}\pi^{0}$ and $\overline{D}^{0}\gamma$
channels, with the $\overline{D}^{0} \rightarrow K^{+}\pi^{-}$ decay. A novel
weighting method is used to subtract background while simultaneously applying
an event-by-event efficiency correction to account for resonant structures in
the decays.
JHEP 07 (2022) 099 A data sample collected with the LHCb detector corresponding to an integrated
luminosity of 9 fb$^{-1}$ is used to measure eleven $CP$ violation observables
in $B^\pm\to Dh^\pm$ ...decays, where $h$ is either a kaon or a pion. The neutral
$D$ meson decay is reconstructed in the three-body final states:
$K^\pm\pi^\mp\pi^0$}; $\pi^+\pi^-\pi^0$; $K^+K^-\pi^0$ and the suppressed
$\pi^\pm K^\mp\pi^0$ combination. The mode where a large $CP$ asymmetry is
expected, $B^\pm\to \pi^\pm K^\mp\pi^0_DK^\pm$, is observed with a
significance greater than seven standard deviations. The ratio of the partial
width of this mode relative to that of the favoured mode, $B^\pm\to
K^\pm\pi^\mp\pi^0_D K^\pm$, is $R_{{\rm ADS}(K)} = (1.27\pm0.16\pm0.02)\times
10^{-2}$. Evidence for a large $CP$ asymmetry is also seen: $A_{{\rm ADS}(K)} =
-0.38\pm0.12\pm0.02$. Constraints on the CKM angle $\gamma$ are calculated from
the eleven reported observables.
JHEP 07 (2022) 026 A precision measurement of the $Z$ boson production cross-section at
$\sqrt{s} = 13$ TeV in the forward region is presented, using $pp$ collision
data collected by the LHCb ...detector, corresponding to an integrated luminosity
of 5.1 fb$^{-1}$. The production cross-section is measured using
$Z\rightarrow\mu^+\mu^-$ events within the fiducial region defined as
pseudorapidity $2.0<\eta<4.5$ and transverse momentum $p_{T}>20$ GeV/$c$ for
both muons and dimuon invariant mass $60<M_{\mu\mu}<120$ GeV/$c^2$. The
integrated cross-section is determined to be \begin{equation*}
\sigma(Z\rightarrow\mu^+\mu^-) = 196.4 \pm 0.2 \pm 1.6 \pm 3.9~pb,
\end{equation*} where the first uncertainty is statistical, the second is
systematic, and the third is due to the luminosity determination. The measured
results are in agreement with theoretical predictions within uncertainties.
