11057739
Initial experience with the CDF layer 00 silicon detector
We report on initial experience with the CDF Layer 00 Detector. Layer 00 is an innovative, low-mass, silicon detector installed in CDF during the upgrade for Run 2A of the Tevatron. Noise pickup present during operation at CDF is discussed. An event-by-event pedestal correction implemented by CDF is presented. This off-line solution prevents L00 from being used in the current incarnation of the on-line displaced track trigger. Preliminary performance of Layer 00 is described.
125438498
Top quark mass measurements
The top quark, with its extraordinarily large mass (nearly that of a gold atom), plays a significant role in the phenomenology of EWSB in the Standard Model. In particular, the top quark mass when combined with the W mass constrains the mass of the as yet unobserved Higgs boson. Thus, a precise determination of the mass of the top quark is a principal goal of the CDF and D0 experiments. With the data collected thus far in Runs 1 and 2 of the Tevatron, CDF and D0 have measured the top quark mass in both the lepton+jets and dilepton decay channels using a variety of complementary experimental techniques. The author presents an overview of the most recent of the measurements.
111000899
Operational experience and performance of the CDFII silicon detector
The CDFII silicon detector consists of 8 layers of double-sided silicon micro-strip sensors totaling 722,432 readout channels, making it one of the largest silicon detectors in present use by an HEP experiment. After nearly 2 years of data taking, we report on our experience operating the complex device. The performance of the CDFII silicon detector is presented and its effect on physics analyses is discussed. The CDFII silicon detector has begun to show measurable effects of radiation damage. These results and their impact on the expected lifetime of the detector are briefly reviewed.
119530771
Acceleration in the linear non-scaling fixed-field alternating-gradient accelerator EMMA
In a fixed-field alternating-gradient (FFAG) accelerator, eliminating pulsed magnet operation permits rapid acceleration to synchrotron energies, but with a much higher beam-pulse repetition rate. Conceived in the 1950s, FFAGs are enjoying renewed interest, fuelled by the need to rapidly accelerate unstable muons for future high-energy physics colliders. Until now a ‘scaling’ principle has been applied to avoid beam blow-up and loss. Removing this restriction produces a new breed of FFAG, a non-scaling variant, allowing powerful advances in machine characteristics. We report on the first non-scaling FFAG, in which orbits are compacted to within 10 mm in radius over an electron momentum range of 12–18 MeV/c. In this strictly linear-gradient FFAG, unstable beam regions are crossed, but acceleration via a novel serpentine channel is so rapid that no significant beam disruption is observed. This result has significant implications for future particle accelerators, particularly muon and high-intensity proton accelerators.
117063283
Measurement of the production cross-section ratio top anti-top + jets to top anti-top inclusive in 106.0 +/- 4.1 pb(-1) of data collected by CDF during Run 1A + 1 $B$ of the Tevatron
119432345
Electroweak symmetry breaking by extra dimensions
Electroweak symmetry breaking may be naturally induced by the observed quark and gauge fields in extra dimensions without a fundamental Higgs field. The authors show that a composite Higgs doublet can arise as a bound state of (t,b){sub L} and a linear combination of the Kaluza-Klein states of t{sub R}, due to QCD in extra dimensions. The top quark mass depends on the number of active t{sub R} Kaluza-Klein modes, and is consistent with the experimental value.
14475053
EXPERIENCE WITH THE GTS-LHC ION SOURCE
For the heavy ion programme of the LHC a new ECRIS type heavy ion source had to be designed and built for Linac3 to fullfill the intensity requirements. Experience acquired during the installation and commissioning of the source and during operation for the LEIR ring commissioning will be presented. The performance of the source and its reliability are evaluated. Further requirements for high reliability, low down time, easy maintenance and for future physics needs will be discussed.
10472717
Chiral multiplets of heavy-light mesons
The recent discovery of a narrow resonance in ${D}_{s}{\ensuremath{\pi}}^{0}$ by the BaBar Collaboration is consistent with the interpretation of a heavy ${J}^{P}{(0}^{+}{,1}^{+})$ spin multiplet. This system is the parity partner of the ground state ${(0}^{\ensuremath{-}}{,1}^{\ensuremath{-}})$ multiplet, which we argue is required in the implementation of ${\mathrm{SU}(3)}_{L}\ifmmode\times\else\texttimes\fi{}{\mathrm{SU}(3)}_{R}$ chiral symmetry in heavy-light meson systems. The ${(0}^{+}{,1}^{+})\ensuremath{\rightarrow}{(0}^{\ensuremath{-}}{,1}^{\ensuremath{-}})+\ensuremath{\pi}$ transition couplings satisfy a Goldberger-Treiman relation, ${g}_{\ensuremath{\pi}}=\ensuremath{\Delta}{M/f}_{\ensuremath{\pi}},$ where $\ensuremath{\Delta}M$ is the mass gap. The BaBar resonance fits the ${0}^{+}$ state, with a kinematically blocked principal decay mode to $D+K.$ The allowed ${D}_{s}+\ensuremath{\pi},$ ${D}_{s}+2\ensuremath{\pi},$ and electromagnetic transitions are computed from the full chiral theory and found to be suppressed, consistent with the narrowness of the state. This state establishes the chiral mass difference for all such heavy-quark chiral multiplets, and precise predictions exist for the analogous ${B}_{s}$ and strange doubly heavy baryon states.
122678636
One Loop Operator Matrix Elements in the Unruh Vacuum
Abstract We present the details of a study of the matrix elements of local operators in the Unruh vacuum for real massive scalar fields in arbitrary d -spatial dimensions (also the Casimir effects for an infinite plane conductor). This state produces negative expectations for renormalized operators such as φ 2 and T μν with the structure of thermal corrections where the temperature is a local Hawking temperature. We trace this to the lack of precise boundary conditions for the theory on the horizon. Though the Minkowski vacuum appears to be populated with Rindler particles, it produces the general coordinate transform of the Minkowski results as dictated by general covariance. A simple corollary is that broken symmetries are not seen to be restored at large acceleration; the dynamical interpretation of this fact by the accelerating observer is surprising.
107927154
Operation of the GTS-LHC Source for the Hadron Injector at CERN
The GTS-LHC ion source, designed and build by CEA Grenoble, was installed and commissioned at CERN in 2005. Since than the source has delivered oxygen and lead ion beams (O 4+ and Pb 27+ from the source, Pb 54+ from the linac) for the commissioning of the Low Energy Ion Ring (LEIR). Results of this operation and attempts to improve the source performance and reliability, and the linac performance will be presented in this paper.