A
bstract
The first measurements of energy spectra and substructure of anti-
k
T
jets in hadronic
Z
0
decays in
e
+
e
−
collisions are presented. The archived
e
+
e
−
annihilation data at a ...center-of-mass energy of 91.2 GeV were collected with the ALEPH detector at LEP in 1994. In addition to inclusive jet and leading dijet energy spectra, various jet substructure observables are analyzed as a function of jet energy which includes groomed and ungroomed jet mass to jet energy ratios, groomed momentum sharing, and groomed jet radius. The results are compared with perturbative QCD calculations and predictions from the S
herpa
, H
erwig
v7.1.5, P
ythia
6, P
ythia
8 and P
yquen
event generators. The jet energy spectra agree with perturbative QCD calculations which include the treatment of logarithms of the jet radius and threshold logarithms. None of the event generators give a fully satisfactory description of the data.
The Fast Timing Micro-Pattern Gaseous Detector (FTM) has been recently introduced as a promising alternative for applications that require improved time resolution, such as high-luminosity ...accelerators and medical imaging. The FTM consists of a stack of several coupled gas layers alternating drift and multiplication stages. The time resolution is determined by the time of the fastest signal among all amplification stages, read out by external electrodes through capacitive couplings. In the present work, we use the Garfield++ simulation toolkit in order to investigate and optimize the FTM performances. Gain, timing, and efficiency of the FTM are studied as a function of different parameters, such as detector geometry, gas mixture, and applied electric fields. The simulations that are presented in this paper show that a time resolution as low as 160 ps can be reached with a 32-layers FTM.
Simulation is a powerful tool for designing new detectors and guide the construction of new prototypes. Advances in photolithography and micro-electronics led to the development of a new family of ...devices named Micro-Pattern Gas Detectors (MPGDs) 1, with main features: flexible geometry; high rate capability (
>
MHz/cm
2
); excellent spatial resolution ( 100µ m); good time resolution (5-10 ns); and reduced radiation length. A new detector layout, named Fast Timing MPGD (FTM), has been recently proposed 2 that would combine both the high spatial resolution and high rate capability of the MPGDs, while improving the time resolution with nearly two orders of magnitude to ~100ps. However charged particle timing with gaseous detector time resolution below 100 ps has been established with another detection scheme 3, this approach might not be able to sustain high particle rates. This contribution investigates the use of the FTM technology for an innovative TOF-PET imaging detector and emphases the importance of full detector simulation to guide the design of the detector geometry and performance.
The first measurements of two-particle angular correlations for charged particles emitted in e+e− collisions at a center-of-mass energy of 91 GeV are presented. The archived data are collected with ...the ALEPH detector at LEP. The correlation functions are measured over a broad range of pseudorapidity and azimuthal angle of the charged particles. Those results are compared to predictions from the PYTHIA event generator. In contrast to the results from high charged particle multiplicity nucleon-nucleon, nucleon-nucleus and nucleus-nucleus collisions, where long-range correlations with a large pseudorapidity gap are observed, no significant enhancement of long-range correlations is observed with respect to PYTHIA predictions, which do not include additional final state interactions of the outgoing partons.
Measurements of two-particle angular correlations of charged particles emitted in hadronic Z decays are presented. The archived e^{+}e^{-} annihilation data at a center-of-mass energy of 91 GeV were ...collected with the ALEPH detector at LEP between 1992 and 1995. The correlation functions are measured over a broad range of pseudorapidity and full azimuth as a function of charged particle multiplicity. No significant long-range correlation is observed in either the lab coordinate analysis or the thrust coordinate analysis, where the latter is sensitive to a medium expanding transverse to the color string between the outgoing qqover ¯ pair from Z boson decays. The associated yield distributions in both analyses are in better agreement with the prediction from the pythia v6.1 event generator than from herwig v7.1.5. They provide new insights to showering and hadronization modeling. These results serve as an important reference to the observed long-range correlation in proton-proton, proton-nucleus, and nucleus-nucleus collisions.
Objective: To evaluate the anticonvulsant effect of the essential oil of Myrothamnus moschatus(M. moschatus) in convulsion induced by pentylenetetrazole and picrotoxin in rodent models.Methods: The ...essential oil of the aerial parts of M. moschatus was extracted by steam distillation. Thereafter, it was injected subcutaneously to rats and mice at escalating doses(0.1–0.8 m L/kg). Ten minutes after drug injection, pentylenetetrazole was injected intraperitoneally to rats and picrotoxin was administered to mice by the same route.Diazepam served as the positive control. Every single animal was placed into transparent cage and observed for convulsive behavior for 30 min by using ordinary security cameras connected to a video recorder. Death occurring for a period of 24 h was also recorded.Results: The essential oil at 0.8 m L/kg completely arrested the pentylenetetrazole-induced convulsion without any sedative effect and delayed its appearance at lower doses, but showed moderate activities on picrotoxin-induced convulsion. For the rats treated with pentylenetetrazole alone, the mortality was 100% within 1 h, but for the rats pre-treated with the essential oil, the mortality was 0%. For the mice treated with picrotoxin, the mortality rate was also 100%, while 20%–100% died in those that had been pre-treated with the oil.Conclusions: The results confirmed at least partly the traditional uses of the smoke of M. moschatus for the management of convulsion, and implied that the essential oil may inhibit the convulsion by GABAergic neuromodulation.
The ALEPH Collaboration 1 took data at the LEP (CERN) electron-positron collider in the period 1989-2000, producing more than 300 scientific papers. While most of the Collaboration activities stopped ...in the last years, the data collected still has physics potential, with new theoretical models emerging, which ask checks with data at the Z and WW production energies. An attempt to revive and preserve the ALEPH Computing Environment is presented; the aim is not only the preservation of the data files (usually called bit preservation), but of the full environment a physicist would need to perform brand new analyses. Technically, a Virtual Machine approach has been chosen, using the VirtualBox platform. Concerning simulated events, the full chain from event generators to physics plots is possible, and reprocessing of data events is also functioning. Interactive tools like the DALI event display can be used on both data and simulated events. The Virtual Machine approach is suited for both interactive usage, and for massive computing using Cloud like approaches.
We present the first measurement of two-particle angular correlations of
charged particles produced in $e^+e^-$ annihilation up to $\sqrt{s}=$ 209 GeV.
This analysis utilized the archived hadronic ...$e^+e^-$ data at center-of-mass
energy between 91 and 209 GeV collected with the ALEPH detector at LEP between
1992 and 2000. The angular correlation functions are measured over a broad
range of pseudorapidity and full azimuth as a function of charged particle
multiplicity for the first time with LEP-2 data. At 91 GeV, no significant
long-range correlation is observed in either the beam coordinate analysis or
the thrust coordinate analysis, where the latter is sensitive to a medium
expanding transverse to the color string between the outgoing $q\bar{q}$ pair
from the Z boson decays. Results with $e^+e^-$ data at higher collision energy
than 91 GeV, providing higher event multiplicity reach up to around 50, are
presented for the first time. The thrust axis analysis shows a long-range
near-side excess in the two-particle correlation function. We performed Fourier
series decomposition of the two-particle correlation functions. In high
multiplicity events with more than 50 particles, the extracted Fourier
coefficients $v_2$ and $v_3$ magnitudes in data are larger than the MC
reference.
The first measurement of two-particle angular correlations for charged
particles produced in $e^+e^-$ annihilation up to $\sqrt{s}$ = 209 GeV is
presented. Hadronic $e^+e^-$ data, archived at ...center-of-mass energies ranging
from 91 to 209 GeV, were collected using the ALEPH detector at LEP between 1992
and 2000. The angular correlation functions have been measured across a wide
range of pseudorapidities and the full azimuth in bins of charged particle
multiplicity. This is the first such measurement using LEP-II data. With LEP-II
data at 91 GeV, neither the beam coordinate analysis nor the thrust coordinate
analysis reveals significant long-range correlations, consistent with the
finding in the previous measurement with the LEP-I sample. Results for $e^+e^-$
data at energies above 91 GeV, which allow for higher event multiplicities
reaching approximately 50, are presented for the first time. A long-range
near-side excess in the correlation function has been identified in the thrust
axis analysis. Moreover, the two-particle correlation functions were decomposed
using a Fourier series, and the resulting Fourier coefficients $v_n$ were
compared with event generator outputs. In events with high multiplicity,
featuring more than 50 particles, the extracted $v_2$ and $v_3$ magnitudes from
the data are higher than those from the Monte Carlo reference.
The first measurement of two-particle angular correlations for charged
particles produced in $e^+e^-$ annihilation up to $\sqrt{s} = 209$ GeV with
LEP-II data is presented. Hadronic $e^+e^-$ data, ...archived at center-of-mass
energies ranging from 183 to 209 GeV, were collected using the ALEPH detector
at LEP. The angular correlation functions have been measured across a wide
range of pseudorapidities and the full azimuth in bins of charged particle
multiplicity. Results for $e^+e^-$ data at high energies, which allow for
higher event multiplicities reaching approximately 50 than LEP-I at Z pole
energy, are presented for the first time. A long-range near-side excess in the
correlation function has been identified in the analysis when calculating
particle kinematic variables with respect to the thrust axis. Moreover, the
two-particle correlation functions were decomposed using a Fourier series, and
the resulting Fourier coefficients $v_n$ were compared with event generator
outputs. In events with high multiplicity featuring more than 50 particles, the
extracted $v_2$ magnitude from the data are compared to those from the Monte
Carlo reference.
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