119 research outputs found
Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at âsNN = 5.02 TeV with the LHCb detector
Flow harmonic coefficients,
v
n
, which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02
TeV
. The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features
Study of the lineshape of the chi(c1) (3872) state
A study of the lineshape of the chi(c1) (3872) state is made using a data sample corresponding to an integrated luminosity of 3 fb(-1) collected in pp collisions at center-of-mass energies of 7 and 8 TeV with the LHCb detector. Candidate chi(c1)(3872) and psi(2S) mesons from b-hadron decays are selected in the J/psi pi(+)pi(-) decay mode. Describing the lineshape with a Breit-Wigner function, the mass splitting between the chi(c1 )(3872) and psi(2S) states, Delta m, and the width of the chi(c1 )(3872) state, Gamma(Bw), are determined to be (Delta m=185.598 +/- 0.067 +/- 0.068 Mev,)(Gamma BW=1.39 +/- 0.24 +/- 0.10 Mev,) where the first uncertainty is statistical and the second systematic. Using a Flatte-inspired model, the mode and full width at half maximum of the lineshape are determined to be (mode=3871.69+0.00+0.05 MeV.)(FWHM=0.22-0.04+0.13+0.07+0.11-0.06-0.13 MeV, ) An investigation of the analytic structure of the Flatte amplitude reveals a pole structure, which is compatible with a quasibound D-0(D) over bar*(0) state but a quasivirtual state is still allowed at the level of 2 standard deviations
Study of CP violation in B0 â DKâ(892)0 decays with D â KÏ(ÏÏ), ÏÏ(ÏÏ), and KK final states
A measurement of CP-violating observables associated with the interference
of B0 â D0Kâ
(892)0 and B0 â DÂŻ 0Kâ
(892)0 decay amplitudes is performed in the
D0 â KâÏ
±(Ï
+Ï
â), D0 â Ï
+Ï
â(Ï
+Ï
â), and D0 â K+Kâ fnal states using data collected
by the LHCb experiment corresponding to an integrated luminosity of 9 fbâ1
. CP-violating
observables related to the interference of B0
s â D0KÂŻ â
(892)0 and B0
s â DÂŻ 0KÂŻ â
(892)0 are also
measured, but no evidence for interference is found. The B0 observables are used to constrain
the parameter space of the CKM angle Îł and the hadronic parameters r
DKâ
B0 and ÎŽ
DKâ
B0 with
inputs from other measurements. In a combined analysis, these measurements allow for four
solutions in the parameter space, only one of which is consistent with the world average
Measurement of the CKM angle in and decays with
A measurement of -violating observables is performed using the decays
and , where the meson is
reconstructed in one of the self-conjugate three-body final states and (commonly denoted ). The decays are analysed in bins of the -decay phase space, leading
to a measurement that is independent of the modelling of the -decay
amplitude. The observables are interpreted in terms of the CKM angle .
Using a data sample corresponding to an integrated luminosity of
collected in proton-proton collisions at centre-of-mass
energies of , , and with the LHCb experiment,
is measured to be . The hadronic
parameters , , , and ,
which are the ratios and strong-phase differences of the suppressed and
favoured decays, are also reported
RECENT CHANGES IN FEDERAL WELFARE LEGISLATION AND THE IMPACT OF REGIONAL ECONOMIC GROWTH ON POVERTY, DEPENDENCY AND WORK INCENTIVES: SOME FINDINGS
Regional economic growth based on private sector job creation is often proposed as a policy for reducing the incidence of regional unemployment, poverty and dependency. One factor that could limit the impact of economic growth on the employment and poverty status of an area's indigenous population is the area's public assistance system. This study evaluates the impact of recent changes in federal welfare legislation (HR 3982) on the work incentives and the poverty and dependency status of Delaware female household heads receiving Aid to Families with Dependent Children (AFDC) assistance. Specifically, the study estimates the implicit marginal tax rates that such household heads would face by accepting employment in private sector jobs to which they are potential entrants under the pre and post HR 3982 conditions. In addition, the study examines the effect of the HR 3982 changes on the poverty and dependency status of such households
FORECASTING AID TO FAMILIES WITH DEPENDENT CHILDREN CASELOADS AND PAYMENTS IN DELAWARE
The purpose of this paper is to present a model which was developed
to forecast Aid to Families with Dependent Children (AFDC) caseloads
and payments in Delaware. The model consists of a caseload equation. a
payments equation. and three labor market equations. The model. which
was fitted statistically using quarterly data for the period 1958-1976,
forecasts significantly better than trend type models. In addition , the
model, unlike trend type models has the potential for forecasting turning
points and can be used to simulate the impact of proposed policy
changes
Cost of Unemployment Insurance for Farmworkers in Selected States
Regression analysis with data for 12 Northeastern States, Ohio, Florida, and Texas explains
93 percent of the variation in cost rates of unemployment insurance coverage among these
States. Of the explained variation in the cost rates of such coverage for farmworkers, 57
percent is accounted for by system variables and 43 percent by labor force variables. Simulation
with a fixed population spotlights the widely varying influences of different States'
qualifying and benefit schedule requirements. Average total benefits per worker ranged
from 486. An attempt was made to adjust the benefit payments to allow for the
cost of living in each State
- âŠ