The Compact Muon Solenoid (CMS) is a general purpose experiment designed to study proton-proton collisions at the Large Hadron Collider (LHC). The CMS L1 Trigger must select interesting collisions at ...a rate smaller than 100 kHz. The CMS Drift Tube (DT) Barrel Muon Trigger performs a full muon tracking analysis in real time for the CMS L1 Trigger. The DT Trigger motivation, hardware implementation, and performance are presented.
Phys.Rev.D71:073008,2005 We present a new, completely revised calculation of the muon anomalous
magnetic moment, $a_\mu=(g_{\mu}-2)/2$, comparing it with the more recent
experimental determination of ...this quantity; this furnishes an important test
of theories of strong, weak and electromagnetic interactions. These theoretical
and experimental determinations give the very precise numbers, $$10^{11}\times
a_\mu=\cases{116 591 806\pm50\pm10 ({\rm rad.})\pm30
(\ell\times\ell)\quad\hbox{Th., no $\tau$}\cr 116 591 889\pm49\pm10 ({\rm
rad.})\pm30 (\ell\times\ell)\quad\hbox{Theory, $\tau$}\cr 116 592
080\pm60\quad\hbox{Experiment}.\cr}$$ In the theoretical evaluations, the
first quantity does not, and the second one does, use information from $\tau$
decay. The first errors for the theoretical evaluations include statistical
plus systematic errors; the other ones are the estimated errors due to
incomplete treatment of radiative corrections and the estimated error in the
light-by-light scattering contribution. We thus have a significant mismatch
between theory and experiment. We also use part of the theoretical calculations
to give a precise evaluation of the electromagnetic coupling on the $Z$,
$\bar{\alpha}_{\rm Q.E.D.}(M^2_{Z})$, of the masses and widths of the (charged
and neutral) rho resonances, of the scattering length and effective range for
the P wave in $\pi\pi$ scattering, and of the quadratic radius and second
coefficient of the pion form factor.
A new combined test of an electromagnetic liquid argon accordion calorimeter and a hadronic scintillating-tile calorimeter was carried out at the CERN SPS. These devices are prototypes of the barrel ...calorimeter of the future ATLAS experiment at the LHC. The energy resolution of pions in the energy range from 10 to 300 GeV at an incident angle
θ of about 12° is well described by the expression
σ/E=((41.9±1.6)%/
E
+(1.8±0.1)%)⊕(1.8±0.1)/E
, where
E is in GeV. The response to electrons and muons was evaluated. Shower profiles, shower leakage and the angular resolution of hadronic showers were also studied. Results are compared with those from the previous beam test.
Phys.Rev. D65 (2002) 093002 We perform a new, detailed calculation of the hadronic contributions to the
running electromagnetic coupling, $\bar{\alpha}$, defined on the Z particle (91
GeV). We find ...for the hadronic contribution, including radiative corrections,
$$10^5\times \deltav_{\rm had.}\alpha(M_Z^2)= 2740\pm12,$$ or, excluding the
top quark contribution, $$10^5\times \deltav_{\rm had.}\alpha^{(5)}(M_Z^2)=
2747\pm12.$$
Adding the pure QED corrections we get a value for the running
electromagnetic coupling of $$\bar{\alpha}_{\rm Q.E.D.}(M_Z^2)=
{{1}\over{128.965\pm0.017}}.$$
Phys.Rev. D65 (2002) 093001 We perform a new calculation of the hadronic contributions, $a({\rm
Hadronic})$ to the anomalous magnetic moment of the muon, $a_\mu$. For the low
energy contributions of ...order $\alpha^2$ we carry over an analysis of the pion
form factor $F_\pi(t)$ using recent data both on $e^+e^-\to\pi^+\pi^-$ and
$\tau^+\to \bar{\nu}_\tau \pi^+\pi^0$. In this analysis we take into account
that the phase of the form factor is equal to that of $\pi\pi$ scattering. This
allows us to profit fully from analyticity properties so we can use also
experimental information on $F_\pi(t)$ at spacelike $t$. At higher energy we
use QCD to supplement experimental data, including the recent measurements of
$e^+e^-\to {\rm hadrons}$ both around 1 GeV and near the $\bar{c}c$ threshold.
This yields a precise determination of the $O(\alpha^2)$ and
$O(\alpha^2)+O(\alpha^3)$ hadronic part of the photon vacuum polarization
pieces, $$10^{11}\times a^{(2)}({\rm h.v.p.})=6 909\pm64;\quad 10^{11}\times
a^{(2+3)}({\rm h.v.p.})=7 002\pm66$$ As byproducts we also get the masses and
widths of the $\rho^0, \rho^+$, and very accurate values for the charge radius
and second coefficient of the pion. Adding the remaining order $\alpha^3$
hadronic contributions we find $$10^{11}\times a^{\rm theory}(\hbox{Hadronic})=
6 993\pm69\quad(e^+e^- + \tau + {\rm spacel.})$$ The figures given are obtained
including $\tau$ decay data. This is to be compared with the recent
experimental value, $$10^{11}\times a^{\rm exp.}(\hbox{Hadronic})=7
174\pm150.$$
We present a new, completely revised calculation of the muon anomalous magnetic moment, \(a_\mu=(g_{\mu}-2)/2\), comparing it with the more recent experimental determination of this quantity; this ...furnishes an important test of theories of strong, weak and electromagnetic interactions. These theoretical and experimental determinations give the very precise numbers, $$10^{11}\times a_\mu=\cases{116 591 806\pm50\pm10 ({\rm rad.})\pm30 (\ell\times\ell)\quad\hbox{Th., no \(\tau\)}\cr 116 591 889\pm49\pm10 ({\rm rad.})\pm30 (\ell\times\ell)\quad\hbox{Theory, \(\tau\)}\cr 116 592 080\pm60\quad\hbox{Experiment}.\cr}$$ In the theoretical evaluations, the first quantity does not, and the second one does, use information from \(\tau\) decay. The first errors for the theoretical evaluations include statistical plus systematic errors; the other ones are the estimated errors due to incomplete treatment of radiative corrections and the estimated error in the light-by-light scattering contribution. We thus have a significant mismatch between theory and experiment. We also use part of the theoretical calculations to give a precise evaluation of the electromagnetic coupling on the \(Z\), \(\bar{\alpha}_{\rm Q.E.D.}(M^2_{Z})\), of the masses and widths of the (charged and neutral) rho resonances, of the scattering length and effective range for the P wave in \(\pi\pi\) scattering, and of the quadratic radius and second coefficient of the pion form factor.
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