A
bstract
Inclusive
ψ
(2S) production is measured in p-Pb collisions at the centre-of-mass energy per nucleon-nucleon pair
s
NN
= 8
.
16 TeV, using the ALICE detector at the CERN LHC. The production ...of
ψ
(2S) is studied at forward (2
.
03
< y
cms
<
3
.
53) and backward (
−
4
.
46
< y
cms
< −
2
.
96) centre-of-mass rapidity and for transverse momentum
p
T
<
12 GeV/
c
via the decay to muon pairs. In this paper, we report the integrated as well as the
y
cms
- and
p
T
-differential inclusive production cross sections. Nuclear effects on
ψ
(2S) production are studied via the determination of the nuclear modification factor that shows a strong suppression at both forward and backward centre-of-mass rapidities. Comparisons with corresponding results for inclusive J/
ψ
show a similar suppression for the two states at forward rapidity (p-going direction), but a stronger suppression for
ψ
(2S) at backward rapidity (Pb-going direction). As a function of
p
T
, no clear dependence of the nuclear modification factor is found. The relative size of nuclear effects on
ψ
(2S) production compared to J/
ψ
is also studied via the double ratio of production cross sections
σ
ψ
(2S)
/σ
J
/ψ
pPb
/
σ
ψ
(2S)
/σ
J
/ψ
pp
between p-Pb and pp collisions. The results are compared with theoretical models that include various effects related to the initial and final state of the collision system and also with previous measurements at
s
NN
= 5
.
02 TeV.
This study examines the pharmacokinetics of oral doses of lithium carbonate immediate-release capsules after administration of 600 or 900 mg in children and adolescents with Diagnostic and ...Statistical Manual of Mental Disorders, Fourth Edition, bipolar I disorder. Lithium plasma concentrations were followed over 48 to 72 hours in 39 subjects (20 male and 19 female subjects; ages, 7-17 years) with mixed or manic episodes enrolled at 7 clinical sites participating in the Collaborative Lithium Trials. Population pharmacokinetic modeling was performed using NONMEM, and influences of patient covariates on pharmacokinetics parameters were examined. The pharmacokinetics of lithium was best described using a 2-compartment model with a lag time and first-order absorption. There was considerable variability in lithium exposures. Lithium clearance related best to fat-free mass. Inclusion of fat-free mass as a covariate reduced the between-subject variability from 52% to 42%. Lithium clearances did not vary systematically with age group, dose, sex, or creatinine clearances. Allometrically scaled clearance and volume of distribution from the population analysis were within the range reported in adults. Single-dose profiles of lithium in young patients with BP-1 show marked variability. Therefore, ongoing serum monitoring is needed during continued therapy. The developed population pharmacokinetic model may be used to predict other dosage regimens, support scaling from adult to pediatric pharmacokinetics, and support the design of future clinical trials.
The measurement of the azimuthal-correlation function of prompt D mesons with charged particles in pp collisions at
s
=
5.02
TeV
and p–Pb collisions at
s
NN
=
5.02
TeV
with the ALICE detector at the ...LHC is reported. The
D
0
,
D
+
, and
D
∗
+
mesons, together with their charge conjugates, were reconstructed at midrapidity in the transverse momentum interval
3
<
p
T
<
24
GeV
/
c
and correlated with charged particles having
p
T
>
0.3
GeV
/
c
and pseudorapidity
|
η
|
<
0.8
. The properties of the correlation peaks appearing in the near- and away-side regions (for
Δ
φ
≈
0
and
Δ
φ
≈
π
, respectively) were extracted via a fit to the azimuthal correlation functions. The shape of the correlation functions and the near- and away-side peak features are found to be consistent in pp and p–Pb collisions, showing no modifications due to nuclear effects within uncertainties. The results are compared with predictions from Monte Carlo simulations performed with the PYTHIA, POWHEG+PYTHIA, HERWIG, and EPOS 3 event generators.
A
bstract
Production of inclusive charmonia in pp collisions at center-of-mass energy of
s
= 13 TeV and p–Pb collisions at center-of-mass energy per nucleon pair of
s
NN
= 8
.
16 TeV is studied as a ...function of charged-particle pseudorapidity density with ALICE. Ground and excited charmonium states (
J/ψ
,
ψ
(2S)) are measured from their dimuon decays in the interval of rapidity in the center-of-mass frame 2
.
5
< y
cms
<
4
.
0 for pp collisions, and 2
.
03
< y
cms
<
3
.
53 and −4
.
46
< y
cms
<
−2
.
96 for p–Pb collisions. The charged-particle pseudorapidity density is measured around midrapidity (|
η
|
<
1
.
0). In pp collisions, the measured charged-particle multiplicity extends to about six times the average value, while in p-Pb collisions at forward (backward) rapidity a multiplicity corresponding to about three (four) times the average is reached. The
ψ
(2S) yield increases with the charged-particle pseudorapidity density. The ratio of
ψ
(2S) over
J/ψ
yield does not show a significant multiplicity dependence in either colliding system, suggesting a similar behavior of
J/ψ
and
ψ
(2S) yields with respect to charged-particle pseudorapidity density. Results for the
ψ
(2S) yield and its ratio with respect to
J/ψ
agree with available model calculations.
A
bstract
The production of strange hadrons (
K
S
0
, Λ, Ξ
±
, and Ω
±
), baryon-to-meson ratios (Λ
/
K
S
0
, Ξ
/
K
S
0
, and Ω
/
K
S
0
), and baryon-to-baryon ratios (Ξ
/
Λ, Ω
/
Λ, and Ω
/
Ξ) ...associated with jets and the underlying event were measured as a function of transverse momentum (
p
T
) in pp collisions at
s
= 13 TeV and p Pb collisions at
s
NN
= 5
.
02 TeV with the ALICE detector at the LHC. The inclusive production of the same particle species and the corresponding ratios are also reported. The production of multi-strange hadrons, Ξ
±
and Ω
±
, and their associated particle ratios in jets and in the underlying event are measured for the first time. In both pp and p–Pb collisions, the baryon-to-meson and baryon-to-baryon yield ratios measured in jets differ from the inclusive particle production for low and intermediate hadron
p
T
(0.6–6 GeV/
c
). Ratios measured in the underlying event are in turn similar to those measured for inclusive particle production. In pp collisions, the particle production in jets is compared with P
ythia
8 predictions with three colour-reconnection implementation modes. None of them fully reproduces the data in the measured hadron
p
T
region. The maximum deviation is observed for Ξ
±
and Ω
±
which reaches a factor of about six. The event multiplicity dependence is further investigated in p−Pb collisions. In contrast to what is observed in the underlying event, there is no significant event-multiplicity dependence for particle production in jets. The presented measurements provide novel constraints on hadronisation and its Monte Carlo description. In particular, they demonstrate that the fragmentation of jets alone is insufficient to describe the strange and multi-strange particle production in hadronic collisions at LHC energies.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract A measurement of the transverse momentum spectra of jets in Pb-Pb collisions at ... = 2.76TeV is reported. Jets ...are reconstructed from charged particles using the anti-k ^sub T^ jet algorithm with jet resolution parameters R of 0.2 and 0.3 in pseudo-rapidity |eta| < 0.5. The transverse momentum p ^sub T^ of charged particles is measured down to 0.15 GeV/c which gives access to the low p ^sub T^ fragments of the jet. Jets found in heavy-ion collisions are corrected event-by-event for average background density and on an inclusive basis (via unfolding) for residual background fluctuations and detector effects. A strong suppression of jet production in central events with respect to peripheral events is observed. The suppression is found to be similar to the suppression of charged hadrons, which suggests that substantial energy is radiated at angles larger than the jet resolution parameter R = 0.3 considered in the analysis. The fragmentation bias introduced by selecting jets with a high p ^sub T^ leading particle, which rejects jets with a soft fragmentation pattern, has a similar effect on the jet yield for central and peripheral events. The ratio of jet spectra with R = 0.2 and R = 0.3 is found to be similar in Pb-Pb and simulated PYTHIA pp events, indicating no strong broadening of the radial jet structure in the reconstructed jets with R < 0.3. Figure not available: see fulltext.
A
bstract
We report about the properties of the underlying event measured with ALICE at the LHC in pp and p–Pb collisions at
$$ \sqrt{s_{\textrm{NN}}} $$
s
NN
= 5
.
02 TeV. The event activity, ...quantified by charged-particle number and summed-
p
T
densities, is measured as a function of the leading-particle transverse momentum
$$ \left({p}_{\textrm{T}}^{\textrm{trig}}\right) $$
p
T
trig
. These quantities are studied in three azimuthal-angle regions relative to the leading particle in the event: toward, away, and transverse. Results are presented for three different
p
T
thresholds (0.15, 0.5 and 1 GeV/
c
) at mid-pseudorapidity (|
η
|
<
0
.
8). The event activity in the transverse region, which is the most sensitive to the underlying event, exhibits similar behaviour in both pp and p–Pb collisions, namely, a steep increase with
$$ {p}_{\textrm{T}}^{\textrm{trig}} $$
p
T
trig
for low
$$ {p}_{\textrm{T}}^{\textrm{trig}} $$
p
T
trig
, followed by a saturation at
$$ {p}_{\textrm{T}}^{\textrm{trig}}\approx 5 $$
p
T
trig
≈
5
GeV/
c
. The results from pp collisions are compared with existing measurements at other centre-of-mass energies. The quantities in the toward and away regions are also analyzed after the subtraction of the contribution measured in the transverse region. The remaining jet-like particle densities are consistent in pp and p–Pb collisions for
$$ {p}_{\textrm{T}}^{\textrm{trig}}>10 $$
p
T
trig
>
10
GeV/
c
, whereas for lower
$$ {p}_{\textrm{T}}^{\textrm{trig}} $$
p
T
trig
values the event activity is slightly higher in p–Pb than in pp collisions. The measurements are compared with predictions from the PYTHIA 8 and EPOS LHC Monte Carlo event generators.
A
bstract
The first measurement of the e
+
e
−
pair production at low lepton pair transverse momentum (
p
T
,
ee
) and low invariant mass (
m
ee
) in non-central Pb–Pb collisions at
$$ ...{\sqrt{s}}_{\textrm{NN}} $$
s
NN
= 5
.
02 TeV at the LHC is presented. The dielectron production is studied with the ALICE detector at midrapidity (
|η
e
| <
0
.
8) as a function of invariant mass (0.4
≤ m
ee
<
2
.
7 GeV/
c
2
) in the 50–70% and 70–90% centrality classes for
p
T
,
ee
<
0.1 GeV/
c
, and as a function of
p
T
,
ee
in three
m
ee
intervals in the most peripheral Pb–Pb collisions. Below a
p
T
,
ee
of 0.1 GeV/
c
, a clear excess of e
+
e
−
pairs is found compared to the expectations from known hadronic sources and predictions of thermal radiation from the medium. The
m
ee
excess spectra are reproduced, within uncertainties, by different predictions of the photon–photon production of dielectrons, where the photons originate from the extremely strong electromagnetic fields generated by the highly Lorentz-contracted Pb nuclei. Lowest-order quantum electrodynamic (QED) calculations, as well as a model that takes into account the impact-parameter dependence of the average transverse momentum of the photons, also provide a good description of the
p
T
,
ee
spectra. The measured
$$ \sqrt{\left\langle {p}_{\textrm{T},\textrm{ee}}^2\right\rangle } $$
p
T
,
ee
2
of the excess
p
T
,
ee
spectrum in peripheral Pb–Pb collisions is found to be comparable to the values observed previously at RHIC in a similar phase-space region.
A
bstract
The
p
T
-differential non-linear flow modes,
v
4
,
22
,
v
5
,
32
,
v
6
,
33
and
v
6
,
222
for
π
±
, K
±
,
K
S
0
, p +
p
¯
, Λ +
Λ
¯
and
ϕ
-meson have been measured for the first time at
s
...NN
= 5
.
02 TeV in Pb-Pb collisions with the ALICE detector at the Large Hadron Collider. The results were obtained with a multi-particle technique, correlating the identified hadrons with reference charged particles from a different pseudorapidity region. These non-linear observables probe the contribution from the second and third order initial spatial anisotropy coefficients to higher flow harmonics. All the characteristic features observed in previous
p
T
-differential anisotropic flow measurements for various particle species are also present in the non-linear flow modes, i.e. increase of magnitude with increasing centrality percentile, mass ordering at low
p
T
and particle type grouping in the intermediate
p
T
range. Hydrodynamical calculations (iEBE-VISHNU) that use different initial conditions and values of shear and bulk viscosity to entropy density ratios are confronted with the data at low transverse momenta. These calculations exhibit a better agreement with the anisotropic flow coefficients than the non-linear flow modes. These observations indicate that non-linear flow modes can provide additional discriminatory power in the study of initial conditions as well as new stringent constraints to hydrodynamical calculations.
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