claudioc/SSPAS2010/cms.tex

\section{The CMS detector}
\label{sec:detector}
A detailed description of the Compact Muon Solenoid (CMS) experiment
can be found elsewhere~\cite{CMS}. The central feature of the CMS detector
is a 3.8~T superconducting solenoid enclosing the
silicon pixel and strip tracker, the crystal electromagnetic
calorimeter (ECAL), and the brass-scintillator hadronic calorimeter
(HCAL).  Muons are measured in gaseous detectors embedded in the iron
return yoke. The ECAL has an energy resolution of better than 0.5\,\% above
100~GeV.  The HCAL, when combined with the ECAL, measures jets with a
resolution $\Delta E/E \approx 100\,\% / \sqrt{E} \oplus 5\,\%$.  The
calorimeter cells are grouped in projective towers, of granularity
$\Delta \eta \times \Delta \phi = 0.087\times0.087$ at central
rapidities and $0.175\times0.175$ in the forward region.
The muons are measured in the pseudorapidity\footnote{Pseudorapidity $\eta$ is defined as $\eta = -\ln(\tan\frac{\theta}{2})$, where
$\theta$ is a polar angle with respect to the direction of the counterclockwise beam} window $|\eta|< 2.4$.  
Matching the muons to the tracks measured in the silicon tracker results in a transverse
momentum resolution between 1 and 5\,\%, for $p_T$ values up to
1~TeV/$c$. The CMS trigger system consists of two levels. The first level (L1), composed of custom
hardware, uses information from the calorimeters and muon
detectors to select a fraction of a per cent of most interesting events for
further readout and analysis. The High Level Trigger
(HLT) processor farm further decreases the event rate to
$\sim 500$~Hz for data storage. The instantaneous luminosity of the machine is measured using information from forward hadronic calorimeters~\cite{lumi}.

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#	User	Rev	Content
1	claudioc	1.1	\section{The CMS detector}
2			\label{sec:detector}
3			A detailed description of the Compact Muon Solenoid (CMS) experiment
4			can be found elsewhere~\cite{CMS}. The central feature of the CMS detector
5			is a 3.8~T superconducting solenoid enclosing the
6			silicon pixel and strip tracker, the crystal electromagnetic
7			calorimeter (ECAL), and the brass-scintillator hadronic calorimeter
8			(HCAL). Muons are measured in gaseous detectors embedded in the iron
9			return yoke. The ECAL has an energy resolution of better than 0.5\,\% above
10			100~GeV. The HCAL, when combined with the ECAL, measures jets with a
11			resolution $\Delta E/E \approx 100\,\% / \sqrt{E} \oplus 5\,\%$. The
12			calorimeter cells are grouped in projective towers, of granularity
13			$\Delta \eta \times \Delta \phi = 0.087\times0.087$ at central
14			rapidities and $0.175\times0.175$ in the forward region.
15			The muons are measured in the pseudorapidity\footnote{Pseudorapidity $\eta$ is defined as $\eta = -\ln(\tan\frac{\theta}{2})$, where
16			$\theta$ is a polar angle with respect to the direction of the counterclockwise beam} window $\|\eta\|< 2.4$.
17			Matching the muons to the tracks measured in the silicon tracker results in a transverse
18			momentum resolution between 1 and 5\,\%, for $p_T$ values up to
19			1~TeV/$c$. The CMS trigger system consists of two levels. The first level (L1), composed of custom
20			hardware, uses information from the calorimeters and muon
21			detectors to select a fraction of a per cent of most interesting events for
22			further readout and analysis. The High Level Trigger
23			(HLT) processor farm further decreases the event rate to
24			$\sim 500$~Hz for data storage. The instantaneous luminosity of the machine is measured using information from forward hadronic calorimeters~\cite{lumi}.
25