The performance of the CMS Level-1 Trigger for supersymmetric events at an LHC luminosity of 2 x 1033 cm-2s-1 is reviewed. Energy and momentum trigger thresholds have been chosen to yield a maximum ...Level-1 output rate of 50 kHz, within a safety factor of three. The Level-1 trigger efficiencies for the majority of the channels studied are found to be greater than 90%, which provides a good basis for the High-Level Trigger, where more stringent conditions are applied. Reasons for occasional lower efficiencies are given.
CMS high-level triggering Neumeister, Norbert
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2001, Letnik:
462, Številka:
1
Journal Article
Recenzirano
The LHC at CERN will provide proton–proton collisions at a centre-of-mass energy of
14
TeV
and a bunch crossing interval of
25
ns
. At design luminosity,
L=10
34
cm
−2
s
−1
, this will result in an ...inelastic pp interaction rate of
1
GHz
. The CMS experiment will have a multi-level trigger system in order to reduce this rate to about
100
Hz
for events written to mass storage. The architecture of the CMS Trigger and Data Acquisition system with emphasis on the High Level Trigger system is described.
The event display and data quality monitoring visualisation systems are especially crucial for commissioning CMS in the imminent CMS physics run at the LHC. They have already proved invaluable for ...the CMS magnet test and cosmic challenge. We describe how these systems are used to navigate and filter the immense amounts of complex event data from the CMS detector and prepare clear and flexible views of the salient features to the shift crews and offline users. These allow shift staff and experts to navigate from a top-level general view to very specific monitoring elements in real time to help validate data quality and ascertain causes of problems. We describe how events may be accessed in the higher level trigger filter farm, at the CERN Tier-0 centre, and in offsite centres to help ensure good data quality at all points in the data processing workflow. Emphasis has been placed on deployment issues in order to ensure that experts and general users may use the visualization systems at CERN, in remote operations and monitoring centres offsite, and from their own desktops.
We have analysed a sample of 2.36 million minimum bias events produced in
p
p
collisions at
s
=630
GeV
in the UA1 experiment at the CERN
Sp
pS
collider. We have studied the production of
K
S
0, Λ and
...Λ
particles with transverse momenta (
p
t
) up to 7 GeV/c and
K
± up to 2 GeV/c. The kaon data are compared with a recent QCD prediction and are found to be in good agreement. The <
p
t
> for
K
S
0, Λ and
Λ
is seen to increase as a function of the charged particle multiplicity and is compared with charged particle production.
From a sample of 2.36 million minimum bias events produced in
p
p
collisions at
s
=630
GeV
in the UA1 experiment and from other published data at the CERN
S
p
p
S
collider we have estimated the ...relative production of
π
±,
π
0,
K
±,
K
S
0, Λ,
Λ
,
p and
p
. We obtain a meson over baryon ratio
M
B
= 6.4 ± 1.1
. From the
K
S
0
π
±
ratio we measure the strangeness suppression factor
λ = 0.29 ± 0.02 ± 0.01 which, combining with other available data provides a new world average of 0.29 ± 0.015. Both the
K
S
0
π
±
ratio and the strangeness suppression factor λ as a function of
s
are investigated, and an extrapolation to the LHC energy is performed.
Endocannabinoids and their attending cannabinoid type 1 (CB1) receptor have been implicated in animal models of post-traumatic stress disorder (PTSD). However, their specific role has not been ...studied in people with PTSD. Herein, we present an in vivo imaging study using positron emission tomography (PET) and the CB1-selective radioligand (11)COMAR in individuals with PTSD, and healthy controls with lifetime histories of trauma (trauma-exposed controls (TC)) and those without such histories (healthy controls (HC)). Untreated individuals with PTSD (N=25) with non-combat trauma histories, and TC (N=12) and HC (N=23) participated in a magnetic resonance imaging scan and a resting PET scan with the CB1 receptor antagonist radiotracer (11)COMAR, which measures the volume of distribution (VT) linearly related to CB1 receptor availability. Peripheral levels of anandamide, 2-arachidonoylglycerol, oleoylethanolamide, palmitoylethanolamide and cortisol were also assessed. In the PTSD group, relative to the HC and TC groups, we found elevated brain-wide (11)COMAR VT values (F(2,53)=7.96, P=0.001; 19.5% and 14.5% higher, respectively), which were most pronounced in women (F(1,53)=5.52, P=0.023). Anandamide concentrations were reduced in the PTSD relative to the TC (53.1% lower) and HC (58.2% lower) groups. Cortisol levels were lower in the PTSD and TC groups relative to the HC group. Three biomarkers examined collectively--OMAR VT, anandamide and cortisol--correctly classified nearly 85% of PTSD cases. These results suggest that abnormal CB1 receptor-mediated anandamide signaling is implicated in the etiology of PTSD, and provide a promising neurobiological model to develop novel, evidence-based pharmacotherapies for this disorder.
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