P. Dauncey

We have measured the mass of the Z boson to be 91.14±0.12 GeV/c2, and its width to be 2.42+0.45−0.35 GeV. If we constrain the visible width to its standard-model value, we find the partial width to invisible decay modes to be 0.46±0.10 GeV, corresponding to 2.8±0.6 neutrino species, with a 95%-confidence-level upper limit of 3.9.Received 12 October 1989DOI:https://doi.org/10.1103/PhysRevLett.63.2173©1989 American Physical Society

The Technical Design for the COMET Phase-I experiment is presented in this paper. COMET is an experiment at J-PARC, Japan, which will search for neutrinoless conversion of muons into electrons in the field of an aluminium nucleus ($\mu-e$ conversion, $\mu^- N \to e^- N$); a lepton flavor violating process. The experimental sensitivity goal for this process in the Phase-I experiment is $3.1\times10^{-15}$, or 90 % upper limit of branching ratio of $7\times 10^{-15}$, which is a factor of 100 improvement over the existing limit. The expected number of background events is 0.032. To achieve the target sensitivity and background level, the 3.2 kW 8 GeV proton beam from J-PARC will be used. Two types of detectors, CyDet and StrECAL, will be used for detecting the \mue conversion events, and for measuring the beam-related background events in view of the Phase-II experiment, respectively. Results from simulation on signal and background estimations are also described.

We have measured the mass of the Z boson to be 91.11±0.23 GeV/c2, and its width to be 1.61+0.60−0.43 GeV. If we constrain the visible width to its standard-model value, we find the partial width to invisible decay modes to be 0.62±0.23 GeV, corresponding to 3.8±1.4 neutrino species.Received 24 July 1989DOI:https://doi.org/10.1103/PhysRevLett.63.724©1989 American Physical Society

An analog hadron calorimeter (AHCAL) prototype of 5.3 nuclear interaction lengths thickness has been constructed by members of the CALICE Collaboration. The AHCAL prototype consists of a 38-layer sandwich structure of steel plates and highly-segmented scintillator tiles that are read out by wavelength-shifting fibers coupled to SiPMs. The signal is amplified and shaped with a custom-designed ASIC. A calibration/monitoring system based on LED light was developed to monitor the SiPM gain and to measure the full SiPM response curve in order to correct for non-linearity. Ultimately, the physics goals are the study of hadron shower shapes and testing the concept of particle flow. The technical goal consists of measuring the performance and reliability of 7608 SiPMs. The AHCAL was commissioned in test beams at DESY and CERN. The entire prototype was completed in 2007 and recorded hadron showers, electron showers and muons at different energies and incident angles in test beams at CERN and Fermilab.

The studies presented in this paper provide a first experimental test of the Particle Flow Algorithm (PFA) concept using data recorded in high granularity calorimeters. Pairs of overlaid pion showers from CALICE 2007 test beam data are reconstructed by the PandoraPFA program developed to implement PFA for a future lepton collider. Recovery of a neutral hadron's energy in the vicinity of a charged hadron is studied. The impact of the two overlapping hadron showers on energy resolution is investigated. The dependence of the confusion error on the distance between a 10 GeV neutral hadron and a charged pion is derived for pion energies of 10 and 30 GeV which are representative of a 100 GeV jet. The comparison of these test beam data results with Monte Carlo simulation is done for various hadron shower models within the GEANT4 framework. The results for simulated particles and for beam data are in good agreement thereby providing support for previous simulation studies of the power of Particle Flow Calorimetry at a future lepton collider.

A common problem in data analysis is that the functional form, as well as the parameter values, of the underlying model which should describe a dataset is not known a priori. In these cases some extra uncertainty must be assigned to the extracted parameters of interest due to lack of exact knowledge of the functional form of the model. A method for assigning an appropriate error is presented. The method is based on considering the choice of functional form as a discrete nuisance parameter which is profiled in an analogous way to continuous nuisance parameters. The bias and coverage of this method are shown to be good when applied to a realistic example.

In this paper we present a novel, quadruple well process developed in a modern 0.18 mm CMOS technology called INMAPS. On top of the standard process, we have added a deep P implant that can be used to form a deep P-well and provide screening of N-wells from the P-doped epitaxial layer. This prevents the collection of radiation-induced charge by unrelated N-wells, typically ones where PMOS transistors are integrated. The design of a sensor specifically tailored to a particle physics experiment is presented, where each 50 mm pixel has over 150 PMOS and NMOS transistors. The sensor has been fabricated in the INMAPS process and first experimental evidence of the effectiveness of this process on charge collection is presented, showing a significant improvement in efficiency.

A prototype silicon–tungsten electromagnetic calorimeter (ECAL) for an international linear collider (ILC) detector was installed and tested during summer and autumn 2006 at CERN. The detector had 6480 silicon pads of dimension 1×1cm2. Data were collected with electron beams in the energy range 6–45 GeV. The analysis described in this paper focuses on electromagnetic shower reconstruction and characterises the ECAL response to electrons in terms of energy resolution and linearity. The detector is linear to within approximately the 1% level and has a relative energy resolution of (16.53±0.14(stat)±0.4(syst))/E(GeV)⊕(1.07±0.07(stat)±0.1(syst))(%). The spatial uniformity and the time stability of the ECAL are also addressed.

The Mark II detector has been upgraded in preparation for its role as the first detector to take data at the Stanford Linear Collider. The new detector components include the central drift chamber, the time-of-flight system, the coil, the endcap electromagnetic calorimeters and the beam energy and luminosity measuring devices. There have also been improvements in detector hermeticity. All of the major components were installed for a test run at the PEP storage ring (√s = 29 GeV) in 1985. This paper describes the upgraded detector, including its trigger and data acquisition systems, and gives performance figures for its components. Future improvements are also discussed.

The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the electromagnetic calorimeter, the current baseline choice is a high granularity sampling calorimeter with tungsten as absorber and silicon detectors as sensitive material. A ``physics prototype'' has been constructed, consisting of thirty sensitive layers. Each layer has an active area of 18 × 18 cm2 and a pad size of 1 × 1 cm2. The absorber thickness totals 24 radiation lengths. It has been exposed in 2006 and 2007 to electron and hadron beams at the DESY and CERN beam test facilities, using a wide range of beam energies and incidence angles. In this paper, the prototype and the data acquisition chain are described and a summary of the data taken in the 2006 beam tests is presented. The methods used to subtract the pedestals and calibrate the detector are detailed. The signal-over-noise ratio has been measured at 7.63±0.01. Some electronics features have been observed; these lead to coherent noise and crosstalk between pads, and also crosstalk between sensitive and passive areas. The performance achieved in terms of uniformity and stability is presented.

We measured the differential jet-multiplicity distribution in ${e}^{+}$${e}^{\mathrm{\ensuremath{-}}}$ annihilation with the Mark II detector. This distribution is compared with the second-order QCD prediction and ${\ensuremath{\alpha}}_{s}$ is determined to be 0.123\ifmmode\pm\else\textpm\fi{}0.009\ifmmode\pm\else\textpm\fi{}0.005 at \ensuremath{\surd}s\ensuremath{\approxeq}${\mathit{M}}_{\mathit{Z}}$ (at the SLAC Linear Collider) and 0.149\ifmmode\pm\else\textpm\fi{}0.002\ifmmode\pm\else\textpm\fi{}0.007 at \ensuremath{\surd}s=29 GeV (at the SLAC storage ring PEP). The running of ${\mathrm{\ensuremath{\alpha}}}_{\mathit{s}}$ between these two center-of-mass energies is consistent with the QCD prediction.

The energy resolution of a highly granular 1 m3 analogue scintillator-steel hadronic calorimeter is studied using charged pions with energies from 10 GeV to 80 GeV at the CERN SPS. The energy resolution for single hadrons is determined to be approximately 58%/sqrt(E/GeV}. This resolution is improved to approximately 45%/sqrt(E/GeV) with software compensation techniques. These techniques take advantage of the event-by-event information about the substructure of hadronic showers which is provided by the imaging capabilities of the calorimeter. The energy reconstruction is improved either with corrections based on the local energy density or by applying a single correction factor to the event energy sum derived from a global measure of the shower energy density. The application of the compensation algorithms to Geant4 simulations yield resolution improvements comparable to those observed for real data.

We have measured inclusive distributions for charged particles in hadronic decays of the Z boson. The variables chosen for study were charged-particle multiplicity, scaled momentum, and momenta transverse to the sphericity axes. The distributions have been corrected for detector effects and are compared with data from ${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ annihilation at lower energies and with the predictions of several QCD-based models. The data are in reasonable agreement with expectations.

Abstract As part of its HL-LHC upgrade program, the CMS collaboration is developing a High Granularity Calorimeter (CE) to replace the existing endcap calorimeters. The CE is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic (CE-E) and hadronic (CE-H) compartments. The calorimeter will be built with ∼30,000 hexagonal silicon modules. Prototype modules have been constructed with 6-inch hexagonal silicon sensors with cell areas of 1.1 cm 2 , and the SKIROC2-CMS readout ASIC. Beam tests of different sampling configurations were conducted with the prototype modules at DESY and CERN in 2017 and 2018. This paper describes the construction and commissioning of the CE calorimeter prototype, the silicon modules used in the construction, their basic performance, and the methods used for their calibration.

We have searched for events with new-particle topologies in 390 hadronic Z decays with the Mark II detector at the SLAC Linear Collider. We place 95%-confidence-level lower limits of 40.7 GeV/${c}^{2}$ for the top-quark mass, 42.0 GeV/${c}^{2}$ for the mass of a fourth-generation charge -(1/3 quark, and 41.3 GeV/${c}^{2}$ for the mass of an unstable Dirac neutral lepton.

The evidence for an accelerating Hubble expansion appears to have confirmed the heuristic prediction, from causal set theory, of a fluctuating and “ever‐present” cosmological term in the Einstein equations. A more concrete phenomenological model incorporating this prediction has been devised and tested, but it remains incomplete. I will review these developments and also mention a possible consequence for the dimensionality of spacetime.

The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the hadronic calorimeter, one option is a highly granular sampling calorimeter with steel as absorber and scintillator layers as active material. High granularity is obtained by segmenting the scintillator into small tiles individually read out via silicon photo-multipliers (SiPM). A prototype has been built, consisting of thirty-eight sensitive layers, segmented into about eight thousand channels. In 2007 the prototype was exposed to positrons and hadrons using the CERN SPS beam, covering a wide range of beam energies and angles of incidence. The challenge of cell equalization and calibration of such a large number of channels is best validated using electromagnetic processes. The response of the prototype steel-scintillator calorimeter, including linearity and uniformity, to electrons is investigated and described.

Calorimeters with a high granularity are a fundamental requirement of the Particle Flow paradigm. This paper focuses on the prototype of a hadron calorimeter with analog readout, consisting of thirty-eight scintillator layers alternating with steel absorber planes. The scintillator plates are finely segmented into tiles individually read out via Silicon Photomultipliers. The presented results are based on data collected with pion beams in the energy range from 8 GeV to 100 GeV. The fine segmentation of the sensitive layers and the high sampling frequency allow for an excellent reconstruction of the spatial development of hadronic showers. A comparison between data and Monte Carlo simulations is presented, concerning both the longitudinal and lateral development of hadronic showers and the global response of the calorimeter. The performance of several GEANT4 physics lists with respect to these observables is evaluated.

Abstract The Compact Muon Solenoid collaboration is designing a new high-granularity endcap calorimeter, HGCAL, to be installed later this decade. As part of this development work, a prototype system was built, with an electromagnetic section consisting of 14 double-sided structures, providing 28 sampling layers. Each sampling layer has an hexagonal module, where a multipad large-area silicon sensor is glued between an electronics circuit board and a metal baseplate. The sensor pads of approximately 1.1 cm 2 are wire-bonded to the circuit board and are readout by custom integrated circuits. The prototype was extensively tested with beams at CERN's Super Proton Synchrotron in 2018. Based on the data collected with beams of positrons, with energies ranging from 20 to 300 GeV, measurements of the energy resolution and linearity, the position and angular resolutions, and the shower shapes are presented and compared to a detailed Geant4 simulation.

We have observed hadronic final states produced in the decays of Z bosons. In order to study the parton structure of these events, we compare the distributions in sphericity, thurst, aplanarity, and number of jets to the predictions of several QCD-based models and to data from lower energies. The data and models agree within the present statistical precision.

We have designed and fabricated a CMOS monolithic active pixel sensor (MAPS) in a novel 0.18 micrometer image-sensor technology (INMAPS) which has a 100% fill factor for charged particle detection and full CMOS electronics in the pixel. The first test sensor using this technology was received from manufacture in July 2007. The key component of the INMAPS process is the implementation of a deep p-well beneath the active circuits. A conventional MAPS design for charged-particle imaging will experience charge sharing between the collection diodes and any PMOS active devices in the pixel which can dramatically reduce the efficiency of the pixel. By implementing a deep p-well, the charge deposited in the epitaxial layer is reflected and conserved for collection at only the exposed collection diode nodes. We have implemented two pixel architectures for charged particle detection. The target application for these pixels is for the sensitive layers of an electromagnetic calorimeter (ECAL) in an international linear collider (ILC) detector. Both pixel architectures contain four n- well diodes for charge-collection; analog front-end circuits for signal pulse shaping; comparator for threshold discrimination; digital logic for threshold trim adjustment and pixel masking. Pixels are served by shared row-logic which stores the location and time-stamp of pixel hits in local SRAM, at the bunch crossing rate of the ILC beam. The sparse hit data are read out from the columns of logic after the bunch train. Here we present design details and preliminary results.

A first prototype of a scintillator strip-based electromagnetic calorimeter was built, consisting of 26 layers of tungsten absorber plates interleaved with planes of 45×10×3 mm3 plastic scintillator strips. Data were collected using a positron test beam at DESY with momenta between 1 and 6 GeV/c. The prototype׳s performance is presented in terms of the linearity and resolution of the energy measurement. These results represent an important milestone in the development of highly granular calorimeters using scintillator strip technology. A number of possible design improvements were identified, which should be implemented in a future detector of this type. This technology is being developed for a future linear collider experiment, aiming at the precise measurement of jet energies using particle flow techniques.

We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters.

We have searched for supersymmetric particles in 528 Z decays with the Mark II detector at the SLAC Linear Collider. We place 95%-confidence-level lower mass limits on degenerate squarks, nondegenerate up-type squarks, nondegenerate down-type squarks, charginos, pair-produced unstable neutralinos, and neutralinos from associated production.Received 19 March 1990DOI:https://doi.org/10.1103/PhysRevLett.64.2984©1990 American Physical Society

Application Specific Integrated Circuits, ASICs, similar to those envisaged for the readout electronics of the central calorimeters of detectors for a future lepton collider have been exposed to high-energy electromagnetic showers. A salient feature of these calorimeters is that the readout electronics will be embedded into the calorimeter layers. In this article it is shown that interactions of shower particles in the volume of the readout electronics do not alter the noise pattern of the ASICs. No signal at or above the MIP level has been observed during the exposure. The upper limit at the 95% confidence level on the frequency of faked signals is smaller than 1x10^{-5} for a noise threshold of about 60% of a MIP. For ASICs with similar design to those which were tested, it can thus be largely excluded that the embedding of the electronics into the calorimeter layers compromises the performance of the calorimeters.

We present a study of a CMOS test sensor which has been designed, fabricated and characterised to investigate the parameters required for a binary readout electromagnetic calorimeter. The sensors were fabricated with several enhancements in addition to standard CMOS processing. Detailed simulations and experimental results of the performance of the sensor are presented. The sensor and pixels are shown to behave in accordance with expectations and the processing enhancements are found to be essential to achieve the performance required.

A prototype module for an International Linear Collider (ILC) detector was built, installed, and tested between 2006 and 2009 at CERN and Fermilab as part of the CALICE test beam program, in order to study the possibilities of extending energy sampling behind a hadronic calorimeter and to study the possibilities of providing muon tracking. The "tail catcher/muon tracker" (TCMT) is composed of 320 extruded scintillator strips (dimensions 1000 mm x 50 mm x 5 mm) packaged in 16 one-meter square planes interleaved between steel plates. The scintillator strips were read out with wavelength shifting fibers and silicon photomultipliers. The planes were arranged with alternating horizontal and vertical strip orientations. Data were collected for muons and pions in the energy range 6 GeV to 80 GeV. Utilizing data taken in 2006, this paper describes the design and construction of the TCMT, performance characteristics, and a beam-based evaluation of the ability of the TCMT to improve hadronic energy resolution in a prototype ILC detector. For a typical configuration of an ILC detector with a coil situated outside a calorimeter system with a thickness of 5.5 nuclear interaction lengths, a TCMT would improve relative energy resolution by 6-16 % for pions between 20 and 80 GeV.

Lepton colliders are considered as options to complement and to extend the physics programme at the Large Hadron Collider. The Compact Linear Collider (CLIC) is an $e^+e^-$ collider under development aiming at centre-of-mass energies of up to 3 TeV. For experiments at CLIC, a hadron sampling calorimeter with tungsten absorber is proposed. Such a calorimeter provides sufficient depth to contain high-energy showers, while allowing a compact size for the surrounding solenoid. A fine-grained calorimeter prototype with tungsten absorber plates and scintillator tiles read out by silicon photomultipliers was built and exposed to particle beams at CERN. Results obtained with electrons, pions and protons of momenta up to 10 GeV are presented in terms of energy resolution and shower shape studies. The results are compared with several GEANT4 simulation models in order to assess the reliability of the Monte Carlo predictions relevant for a future experiment at CLIC.

To extract the physics required at the International Linear Collider, the detectors will need a jet energy resolution of 30%/radicE (GeV). The most promising approach to reach that goal is the use of particle flow algorithms. Particle flow algorithms measure jet energies by combining both tracking and calorimeter information. This requires the use of highly granular calorimeter systems. For the electromagnetic calorimeter (ECAL) the choice is to use silicon-tungsten sampling calorimeters with a highly granular readout. We propose to use Monolithic Active Pixel Sensors (MAPS) as both sensor and readout for such a calorimeter. This novel design would have an extremely fine granularity of 50 x 50 mum <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> with binary readout. With a total area of 2000 m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> of silicon this leads to a "Tera-Pixel" ECAL. An overview of the MAPS detector concept will be given along with the potential advantages of this design. For the optimization of the design detailed sensor simulations have been used. A first prototype sensor using MAPS has been produced and we show first results obtained with this sensor. We also address system level issues like the required DAQ bandwidth and the power consumption.

A silicon strip vertex detector consisting of 36 modules has been built and operated in the Mark II solenoidal detector at the Stanford Linear Collider. The construction of the detector modules, their performance tests, the stability and accuracy of their placement, and the precision alignment of the complete device prior to and after installation are discussed. We also describe the operation of the vertex detector, and we discuss the measurement of impact parameters of charged particle tracks in conjunction with the Mark II wire drift chambers.

Using isolated leptons reconstructed in the Mark II detector to tag bb\ifmmode\bar\else\textasciimacron\fi{} events, we measure the fraction of bb\ifmmode\bar\else\textasciimacron\fi{} events in hadronic ${\mathit{Z}}^{0}$ decays to be 0.${23}_{\mathrm{\ensuremath{-}}0.09}^{+0.11}$, in good agreement with the standard-model prediction of 0.22. We find \ensuremath{\Gamma}(Z\ensuremath{\rightarrow}bb\ifmmode\bar\else\textasciimacron\fi{})=0.${43}_{\mathrm{\ensuremath{-}}0.17}^{+0.21}$ GeV.

We present measurements by the Mark II experiment of the ratios of the leptonic partial widths of the Z boson to the hadronic partial width. The results are ${\mathrm{\ensuremath{\Gamma}}}_{\mathit{ee}}$/${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{had}}$=0.${037}_{\mathrm{\ensuremath{-}}0.012}^{+0.016}$, =0.${053}_{\mathrm{\ensuremath{-}}0.015}^{0.020}$, and ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{\ensuremath{\tau}}\mathrm{\ensuremath{\tau}}}$/${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{had}}$=0.${066}_{\mathrm{\ensuremath{-}}0.017}^{+0.021}$, in good agreement with the standard-model prediction of 0.048. From the average leptonic width result, ${\mathrm{\ensuremath{\Gamma}}}_{\mathit{ll}}$/${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{had}}$=0.${053}_{\mathrm{\ensuremath{-}}0.009}^{+0.010}$, we derive ${\mathrm{\ensuremath{\Gamma}}}_{\mathrm{had}}$=1.${56}_{\mathrm{\ensuremath{-}}0.24}^{+0.28}$ GeV. We find for the vector coupling constants of the tau and muon ${\mathit{v}}_{\mathrm{\ensuremath{\tau}}}^{2}$=0.31\ifmmode\pm\else\textpm\fi{}0.${31}_{\mathrm{\ensuremath{-}}0.30}^{+0.43}$ and ${\mathit{v}}_{\mathrm{\ensuremath{\mu}}}^{2}$=0.05\ifmmode\pm\else\textpm\fi{}0.${30}_{\mathrm{\ensuremath{-}}0.23}^{+0.34}$.

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The CALICE collaboration is studying the design of high performance electromagnetic and hadronic calorimeters for future International Linear Collider detectors. For the electromagnetic calorimeter, the current baseline choice is a high granularity sampling calorimeter with tungsten as absorber and silicon detectors as sensitive material. A ``physics prototype'' has been constructed, consisting of thirty sensitive layers. Each layer has an active area of 18x18 cm2 and a pad size of 1x1 cm2. The absorber thickness totals 24 radiation lengths. It has been exposed in 2006 and 2007 to electron and hadron beams at the DESY and CERN beam test facilities, using a wide range of beam energies and incidence angles. In this paper, the prototype and the data acquisition chain are described and a summary of the data taken in the 2006 beam tests is presented. The methods used to subtract the pedestals and calibrate the detector are detailed. The signal-over-noise ratio has been measured at 7.63 +/- 0.01. Some electronics features have been observed; these lead to coherent noise and crosstalk between pads, and also crosstalk between sensitive and passive areas. The performance achieved in terms of uniformity and stability is presented.

We have measured the fraction of bb\ifmmode\bar\else\textasciimacron\fi{} events in hadronic ${\mathit{Z}}^{0}$ decays, ${\mathit{R}}_{\mathit{b}\mathit{b}\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}$, using the vertex detector system of the Mark II detector at the SLAC Linear Collider. We tag bb\ifmmode\bar\else\textasciimacron\fi{} events by requiring the coincidence of three or more tracks with significant impact parameters. This tag is 50% efficient and results in a sample of 85% purity. We find ${\mathit{R}}_{\mathit{b}\mathit{b}\mathrm{\ifmmode\bar\else\textasciimacron\fi{}}}$=0.251\ifmmode\pm\else\textpm\fi{}0.049\ifmmode\pm\else\textpm\fi{}0.030, in good agreement with other measurements and the standard model prediction.

We describe a search for the decay of the Z boson into pairs of doubly charged Higgs bosons with the Mark II detector operating at the SLAC Linear Collider. Each Higgs boson is assumed to decay into a same-sign leptonic pair. No event candidates are found in a sample of 528 Z decays. At the 95% confidence level, this result excludes the region of leptonic coupling ${\mathit{g}}_{\mathit{l}\mathit{l}}$&gt;3\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}7}$ and Higgs-boson mass 6.5${\mathit{M}}_{\mathit{H}}$36.5 GeV/${\mathit{c}}^{2}$ for isotriplet (left-handed) Higgs bosons. Isosinglet (right-handed) Higgs bosons are excluded in the same ${\mathit{g}}_{\mathit{l}\mathit{l}}$ interval and in the mass interval 7.3${\mathit{M}}_{\mathit{H}}$34.3 GeV/${\mathit{c}}^{2}$.

The design and status of a silicon strip vertex detector for the Mark II experiment at the SLAC Linear Collider are described.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation T. Bruch, CDMS Collaboration; Status and future of the CDMS experiment: CDMS‐II to SuperCDMS. AIP Conf. Proc. 20 November 2007; 957 (1): 193–196. https://doi.org/10.1063/1.2823758 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

We have developed monolithic silicon pixel sensors as study devices for a digital electromagnetic calorimetry application at future collider detectors, such as a linear collider.The motivation for a digital ECAL and the sensor requirements which arise from this are discussed.We present results from the "TPAC" CMOS sensors produced using the 0.18 µm INMAPS process.The sensors have 50 µm pixel size.The technology is also applicable to tracking and vertexing applications where highly granular pixels with integrated in-pixel readout is needed.Several varieties of the TPAC sensors were fabricated with and without some of the various processing innovations available in INMAPS, specifically deep P-wells and high-resistivity epitaxial silicon.The performance of these sensor variants has been measured both in the laboratory and at beam tests.Comparisons of these sensors with each other are presented, showing that the INMAPS innovations result in significant improvements in the sensor performance.

Using an impact-parameter tag to select an enriched sample of ${Z}^{0}\ensuremath{\rightarrow}b\overline{b}$ events, we have measured the difference between the average charged multiplicity of $b\overline{b}$ and all hadronic ${Z}^{0}$ decays to be 2.1\ifmmode\pm\else\textpm\fi{}1.8(stat)\ifmmode\pm\else\textpm\fi{}0.6(syst) tracks per event. The resulting total (nonleading) charged multiplicity for ${Z}^{0}\ensuremath{\rightarrow}b\overline{b}$ events is 23.1(12.0)\ifmmode\pm\else\textpm\fi{}1.8\ifmmode\pm\else\textpm\fi{}0.6 tracks. A comparison of this nonleading multiplicity to hadronic multiplicity data in the range of 10 to 60 GeV supports the hypothesis of flavor-independent hadronic fragmentation, and yields a measurement of the average energy fraction of bottom hadrons in ${Z}^{0}$ decays of ${〈{x}_{E}〉}_{b}=0.62\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.04$.

O'Raifeartaigh models with general R‐charge assignments can have vacua where both supersymmetry and R‐symmetry are spontaneously broken. Most of these vacua are metastable because the potential shows a runaway behaviour. We explain the relation between runaway directions and R‐symmetry.

A silicon-strip vertex detector is being constructed for use in the Mark II detector in the study of Z/sup 0/ decays at the SLAC Linear Collider. The status of the project, including the performance of the individual silicon detector modules, is presented. The discussion covers beam tests, vertex resolution, detector modules, module performance, and mechanical support and alignment.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A class of generalized Randall‐Sundrum type II (RS) brane‐world models with Weyl fluid are confronted with the Gold supernovae data set and BBN constraints. We consider three models with different evolutionary history of the Weyl fluid, characterized by the parameter α. For α = 0 the Weyl curvature of the bulk appears as dark radiation on the brane, while for α = 2 and 3 the brane radiates, leaving a Weyl fluid on the brane with energy density decreasing slower than that of (dark) matter. In each case the contribution Ωd of the Weyl fluid represents but a few percent of the energy content of the Universe. All models fit reasonably well the Gold2006 data. The best fit model for α = 0 is for Ωd = 0.04. In order to obey BBN constraints in this model however, the brane had to radiate at earlier times.

The TeraPixel Active Calorimeter (TPAC) sensor is a novel Monolithic Active Pixel Sensors (MAPS) device developed for use as the active layers of a large area, digital electromagnetic calorimeter (DECAL) at a future e+e− collider. Further applications, which include the tracking and vertex systems for future lepton colliders and LHC upgrades have been proposed and it is therefore essential to characterise the behaviour of the sensor for these applications. We present the first studies of radiation hardness testing of the TPAC sensor. The performance of the sensor has been evaluated after exposures up to 5 Mrad of 50 keV x-rays. Under realistic ILC operating conditions a maximum decrease in the signal to noise ratio of 8% (15%) was observed after 200 krad (5 Mrad) which is already sufficient for proposed applications in future e+e− colliders.

We search for events in the Mark II detector at SLAC Linear Collider with the topology of a Z boson decaying into a pair of long-lived massive particles. No events that are consistent with the search hypothesis are found. Interpreting the long-lived particle as a sequential Dirac neutrino ${\ensuremath{\nu}}_{4}$ of the fourth generation, we exclude at the 95% confidence level a significant range of mixing-matrix elements of ${\ensuremath{\nu}}_{4}$ to other-generation neutrinos for a ${\ensuremath{\nu}}_{4}$ mass from 10 to 43 GeV/${\mathit{c}}^{2}$.

We present a mechanism to create vortices in a plasma via gravitational dragging behind rotating cosmic string loops. The vortical motions create magnetic fields by means of the Harrison‐Rees mechanism; the fields are further enhanced through galactic collapse and dynamo amplification. Employing the Velocity dependent One Scale model (VOS) for the string network and incorporating loop dynamics, we compute the magnetic fields generated around the time of decoupling: these are just strong and coherent enough to account for presently observed magnetic fields in spiral galaxies if efficient dynamos with Γdy−1≈0.3 Gyr are present.

A search for pair production of stable charged particles from Z decay has been performed with the Mark II detector at the SLAC Linear Collider. Particle masses are determined from momentum, ionization energy loss, and time-of-flight measurements. A limit excluding pair production of stable fourth-generation charged leptons and stable mirror fermions with masses between the muon mass and 36.3 GeV/c2 is set at the 95% confidence level. Pair production of stable supersymmetric scalar leptons with masses between the muon mass and 32.6 GeV/c2 is also excluded.Received 5 March 1990DOI:https://doi.org/10.1103/PhysRevLett.64.2980©1990 American Physical Society

Using the Mark II detector at the SLAC Linear Collider, we search for decays of the Z boson to a pair of nonminimal Higgs bosons (Z→Hs0Hp0), where one of them is relatively light (≲10 GeV). We find no evidence for these decays and we obtain limits on the ZHs0Hp0 coupling as a function of the Higgs-boson masses.Received 12 February 1990DOI:https://doi.org/10.1103/PhysRevLett.64.2881©1990 American Physical Society

I discuss the possibility of using a massive vector field to generate the density perturbation in the Universe. I find that a scale‐invariant superhorizon spectrum of vector field perturbations is possible to generate during inflation. The associated curvature perturbation is imprinted onto the Universe following the curvaton scenario. The mechanism does not generate a long‐range anisotropy because an oscillating massive vector field behaves as a pressureless isotropic fluid.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Damien A. Easson; Spinflation and Cycling Branes in Warped Throats. AIP Conf. Proc. 20 November 2007; 957 (1): 313–316. https://doi.org/10.1063/1.2823790 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

As part of its HL-LHC upgrade program, the CMS collaboration is replacing its existing endcap calorimeters with a high-granularity calorimeter (CE). The new calorimeter is a sampling calorimeter with unprecedented transverse and longitudinal readout for both electromagnetic and hadronic compartments. Due to its compactness, intrinsic time resolution, and radiation hardness, silicon has been chosen as active material for the regions exposed to higher radiation levels. The silicon sensors are fabricated as 20 cm (8") wide hexagonal wafers and are segmented into several hundred pads which are read out individually. As part of the sensor qualification strategy, 8" sensor irradiation with neutrons has been conducted at the Rhode Island Nuclear Science Center (RINSC) and followed by their electrical characterisation in 2020-21. The completion of this important milestone in the CE's R&D program is documented in this paper and it provides detailed account of the associated infrastructure and procedures. The results on the electrical properties of the irradiated CE silicon sensors are presented.

For the ILC physics program, the detectors will need an unprecedented jet energy resolution. For the electromagnetic calorimeter, the use of a highly granular silicon-tungsten calorimeter has been proposed. We have developed a Monolithic Active Pixel-based readout for such a calorimeter, which will have extremely fine granularity and will make use of a digital readout. The first generation chip (TPAC1) implements a 168x168 array comprising 50x50 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> pixels. Each pixel has an integrated charge pre-amplifier and comparator. TPACI has been manufactured in the 0.18 μm INMAPS process which includes a deep p-well. We present results of the performance of the TPACI chip together with comparison to simulations and give an outlook to the second generation chip.

The existence of a primordial magnetic field (PMF) would affect both the temperature and polarization anisotropies of the cosmic microwave background (CMB). It also provides a plausible explanation for the disparity between observations and theoretical fits to the CMB power spectrum. Here we report on calculations of not only the numerical power spectrum of the PMF, but also the correlations between the PMF power spectrum and the primary curvature perturbations.

Abstract

The pattern of neutrino masses and mixings is characteristically different from those observed in the quark sector. I discuss why this should be the case and what implications this has for the origin of quark and lepton masses, mixings and CP violation.

The report describes the status of the calorimeter R&D for ILC detector performed in the CALICE collaboration. This status has been presented to the review panel at the LCWS07 workshop at DESY in June 2007.

We have tested the first 4T Monolithic Active Pixel Sensor (MAPS) for particle physics, FORTIS in a beam test. We have measured a signal-to-noise ratio of more than 100 for MIPs due to the excellent noise performance of the 4T architecture. Two versions of the sensor were tested; with and without deep P-well areas in-pixel. The deep P-well areas allow the incorporation of PMOS transistors inside the pixels without signal charge loss. The measured position resolutions were around 2 μm.

Abstract Silicon strip vertex detector consisting of 36 independent detector modules is being constructed for use in the Mark II detector at a SLAC Linear Collider. This paper describes a method for determining the relative alignment of the modules to a precision better than the 5 μm intrinsic resolution of the detectors. The basic procedure involves moving the vertex detector by known amounts through a fixed, collimated X-ray beam, and using the beam position reconstructed from the detected signals to determine the relative positions and orientations of the modules. Results from tests of the method on a subset of detectors are presented.

Using the sample of neutral vector bosons (Z's) produced at the SLAC Linear Collider and detected with the MARK II detector, we search for the decay of the 2

This note describes R&amp;D to be carried out on the data acquisition system for a calorimeter at the future International Linear Collider. A generic calorimeter and data acquisition system is described. Within this framework modified designs and potential bottlenecks within the current system are described. Solutions leading up to a technical design report will to be carried out within CALICE-UK groups.

We present results from the PSI test beam run for the electromagnetic calorimeter of the BABAR experiment. A system of 25 CsI(Tl) crystals was tested with electrons and pions in the momentum range from 100 to 405 MeV/c. Results are presented on crystal light output, on coherent and incoherent noise, on energy resolution and on spatial resolution. The design energy resolutions of the Technical Design Report of BABAR were achieved.

The majority of the proposed detector concepts for the ILC are built around the particle flow algorithm (PFA) approach which requires a highly granular calorimeter. The leading proposed technology for a PFA electromagnetic calorimeter at the ILC is using silicon-tungsten. We have developed a monolithic active pixel sensor for silicon-tungsten calorimeters, which would have extremely fine granularity, allowing binary pixel readout and the usage of digital electromagnetic calorimetry. A first generation chip (TPAC 1.0) has been fabricated, which contains a 168 × 168 pixel array, consisting of 50 × 50 μ m 2 pixels with integrated charge pre-amplifier and comparator. TPAC 1.0 has been manufactured in the 180 nm CMOS INMAPS process which includes a deep p-well implant. We present recent results of the performance of the TPAC 1.0 chip and give an outlook on its successor TPAC 1.1.

The leading proposed technology for electromagnetic calorimeters for ILC detectors is a highly granular silicontungsten calorimeter. We have developed an active pixel sensor for such a calorimeter, which would have extremely fine granularity, allowing binary pixel readout. A first generation chip (TPAC1.0) has been fabricated, and this contains a 168x168 pixel array, consisting of 50x50 micron pixels. Each pixel has an integrated charge pre-amplifier and comparator. TPAC1.0 has been manufactured in a 0.18 micron CMOS “INMAPS” process which includes a deep pwell implant. We present recent results of the performance of the TPAC1.0 sensor together with comparison to device-level simulations.

We present the idea of the GAJET experiment, whose aim is to measure CP asymmetries in B-meson decays at LHC. We propose to construct a spectrometer around the LHC beam pipe using a gas-jet internal target which provides a point-like source. The main consideration of the experiment is to design a first-level trigger which is fast, flexible, robust and technically simple.

Intersecting stacks of supersymmetric fractional branes on the Z6′ orientifold may be used to construct the supersymmetric Standard Model. We construct a four‐stack model, which has the matter spectrum of the supersymmetric Standard Model, including a single pair of Higgs doublets, plus three neutrino‐singlet states. However, the gauge group is SU(3)colour×SU(2)L×U(1)Y×U(1), and there is no overall cancellation of Ramond‐Ramond tadpoles

After a brief description of the main experiments dedicated to the study of high‐energy cosmic rays, the results of the Auger Observatory on anisotropy, mass composition and energy spectrum are presented and compared to those of the other experiments.

In a compact space with non‐trivial cycles, for sufficiently small values of the compact dimensions, charge conjugation (C), spatial reflection (P) and time reversal (J) are spontaneously broken in QCD. The order parameter for the symmetry breaking is the trace of the Wilson line wrapping around the compact dimension, which acquires an imaginary part in the broken phase. We show that a physical signature for the symmetry breaking is a persistent baryonic current wrapping in the compact directions. The existence of such a current is derived analytically at first order in perturbation theory and confirmed in the non‐perturbative regime by lattice simulations.

D‐brane instantons can generate open string couplings in the superpotential which violate global abelian symmetries and are therefore perturbatively forbidden. After discussing the main ingredients, focussing for concretenes on Type IIA orientifold compactifications, we exemplify the generation of perturbatively forbidden Yukawa couplings as well as Majorana mass terms for right‐handed neutrinos in SU(5) GUT‐like models.

Recent data and new data analysis methods show that most probably the parameter w in the equation of state of the dark energy is smaller than −1 at low redshifts. We briefly review some of the models with such a property and without violating null energy condition. We investigate the difference between the observables and predictions of these models, and how they can be explored to single out or constrain the origin of dark energy and its properties.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Neil Turok; Quantum Resolution of Cosmological Singularities using AdS/CFT. AIP Conf. Proc. 20 November 2007; 957 (1): 164–173. https://doi.org/10.1063/1.2823752 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search

We propose a new scenario for D‐term inflation which appears quite straightforwardly in the open string sector of intersecting brane models. We take the inflaton to be a chiral field in a bifundamental representation of the hidden sector and we argue that a sufficiently flat potential can be brane engineered. This type of model generically predicts a near gaussian red spectrum with negligible tensor modes.

Large‐volume models are a promising approach to stabilising moduli and generating the weak hierarchy through TeV‐supersymmetry. I describe the pattern of sparticle mass spectra that arises in these models.

Since May 1999 the BABAR detector has been taking data at the PEP-II asymmetric electron-positron collider at the Stanford Linear Accelerator Center, California. This experiment requires a very large data sample and the PEP-II accelerator uses intense beams to deliver the high collision rates needed. This poses a severe challenge to the BaBar trigger system, which must reject the large rate of background signals resulting from the high beam currents whilst accepting the collisions of interest with very high efficiency. One of the systems that performs this task is the Level 1 Calorimeter Trigger, which identifies energy deposits left by particles in the BABAR calorimeter. It is a digital, custom, fixed latency system which makes heavy use of high-speed FPGA devices to allow flexibility in the choice of data filtering algorithms. Results from several intermediate processing stages are read out, allowing the selection algorithm to be fully analysed and optimized offline. In addition, the trigger is monitored in real time by sampling these data and cross-checking each stage of the trigger calculation against a software model. The design, implementation, construction and performance of the Level 1 Calorimeter Trigger during the first year of BABAR operation are presented.

After a brief discussion of the statistics available to the four LEP experiments at the time of writing and an overview of B-event characteristics, the authors consider in particular the theory, practice and potential pitfalls of neural networks, a new approach to B tagging which attracted a great deal of interest. They then consider some of the QCD aspects of heavy flavour physics. Finally there is a brief discussion of the prospects for heavy flavour physics at HERA.

A silicon strip vertex detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). The performance of the individual modules and the stability and accuracy of their placement in the mechanical support are discussed. Top gain operational experience at the SLC, a telescope made of three silicon detector modules has been assembled and placed inside the Mark II. Results from the first data run of the SLC on the overall performance of the telescope, including backgrounds, charged particle tracking, and spatial resolution, are presented.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

We investigate the three dimensional substructure of hadronic showers in the CALICE scintillator-steel hadronic calorimeter. The high granularity of the detector is used to find track segments of minimum ionising particles within hadronic showers, providing sensitivity to the spatial structure and the details of secondary particle production in hadronic cascades. The multiplicity, length and angular distribution of identified track segments are compared to GEANT4 simulations with several different shower models. Track segments also provide the possibility for in-situ calibration of highly granular calorimeters.

We have developed monolithic silicon pixel sensors as study devices for a digital electromagnetic calorimetry application at future collider detectors, such as a linear collider. The motivation for a digital ECAL and the sensor requirements which arise from this are discussed. We present results from the CMOS sensors produced using the 0.18 μm INMAPS process. The sensors have 50 μm pixel size. The technology is also applicable to tracking and vertexing applications where highly granular pixels with integrated in-pixel readout is needed. Several varieties of the TPAC sensors were fabricated with and without some of the various processing innovations available in INMAPS, specifically deep P-wells and high-resistivity epitaxial silicon. The performance of these sensor variants has been measured both in the laboratory and at beam tests. Comparisons of these sensors with each other are presented, showing that the INMAPS innovations result in significant improvements in the sensor performance.

In this paper we present a novel, quadruple well process developed in a modern 0.18mu CMOS technology called INMAPS. On top of the standard process, we have added a deep P implant that can be used to form a deep P-well and provide screening of N-wells from the P-doped epitaxial layer. This prevents the collection of radiation-induced charge by unrelated N-wells, typically ones where PMOS transistors are integrated. The design of a sensor specifically tailored to a particle physics experiment is presented, where each 50mu pixel has over 150 PMOS and NMOS transistors. The sensor has been fabricated in the INMAPS process and first experimental evidence of the effectiveness of this process on charge collection is presented, showing a significant improvement in efficiency.

Recently, path equations have been obtained for charged and spinning objects in brane world models, using a modified Bazanski Lagrangian. In this study, path deviation equations of extended objects are derived. The significance of moving extended objects in brane world models is examined. Motion in non‐symmetric brane world models is also considered.

Abstract

WIMP models of cold dark matter which exhibit nearly degenerate excited states have a number of interesting signatures that may prove relevant for direct and indirect searches. Such near‐degeneracies form a qualitatively distinct regime in the parameter space of many models which, generically due to the little hierarchy problem, now require efficient co‐annihilation to ensure the correct relic density. This work discusses the relevance of such scenarios for explaining the observed galactic 511 keV line, and also the impact on direct terrestrial searches which may be complicated by recombination‐type processes.

We discuss how the detailed geometry of warped compactification can significantly impact collider data. We show how the details of the cross section for dilepton production (such as the spacing, the width, and the peaks of the KK graviton resonances) for a generic class of warped throats which are closely related to the Randall‐Sundrum model depend sensitively on the precise shape of the warp factor.

Recent searches for non‐SUSY exotics in pp̄ collisions at a center‐of‐mass energy of 1.96 TeV at the Tevatron Run II are reported. The emphasis is put on the results of model‐driven analyses which were updated to the full Run IIa datasets corresponding to integrated luminosities of about 1 fb−1.

In the Brans‐Dicke theory the Planck mass is replaced by a dynamical scalar field. We consider here the supersymmetric analogous of this mechanism replacing in the supergravity Lagrangian the Planck mass with a chiral superfield. This analysis is motivated by the research of possible connections between supersymmetric Dark Matter scenarios and Dark Energy models based on Brans‐Dicke‐like theories. We find that, contrary to the original Brans‐Dicke theory, in its supersymmetric analogous the gravitational sector does not couple to the matter sector in a universal metric way. As a result, violations of the weak equivalence principle could be present in such a scenario.

We discuss the quark EDMs and CEDMs in the MSSM with general flavor‐changing terms in the squark mass matrices. In particular, the charged‐Higgs mediated contributions to the down‐quark EDM and CEDM are evaluated at two‐loop level. We point out that these two‐loop contributions may dominate over the one‐loop induced gluino contribution even when the squark and gluino masses are around few TeV and tan β is moderate.

We present a new model of dark energy which could explain the observed accelerated expansion of our Universe. We show that a five‐dimensional Einstein‐Yang‐Mills theory defined in a flat Friedmann‐Robertson‐Walker universe compactified on a circle possesses degenerate vacua in four dimensions. The present Universe could be trapped in one of these degenerate vacua. With the natural requirement that the size of the extra dimension could be of the GUT scale or smaller, the energy density difference between the degenerate vacua and the true ground state can provide us with just the right amount of dark energy to account for the observed expansion rate of our Universe.

Abstract

We review why detection of non‐Gaussianity in the spectrum of primordial fluctuations would be an indication of interesting inflationary physics and discuss the observational constraints on a simple type of scale‐dependent non‐Gaussianity. In particular, if the amount non‐Gaussianity increases during inflation then observations on scales smaller than those probed by the Cosmic Microwave Background may provide important constraints. Clusters number counts can be a useful tool in this context.

We analyze the effect of variation of fundamental couplings and mass scales on primordial nucleosynthesis in a systematic way. The first step establishes the response of primordial element abundances to the variation of a large number of nuclear physics parameters, including nuclear binding energies. We find a strong influence of the n‐p mass difference, of the nucleon mass and of A = 3,4,7 binding energies. A second step relates the nuclear parameters to the parameters of the Standard Model of particle physics. The deuterium, and, above all, 7Li abundances depend strongly on the average light quark mass. We calculate the behaviour of abundances when variations of fundamental parameters obey relations arising from grand unification. We also discuss the possibility of a substantial shift in the lithium abundance while the deuterium and 4He abundances are only weakly affected.

The CDF and DO/ collaborations at the Tevatron have produced exquisite precision measurements on high‐PT physics with their large datasets of pp̄ collisions. The top quark is being studied in great detail, and a precision of 1.1% in the measurement of its mass has been achieved. The large datasets of W and Z boson decays have allowed the most precise measurement of the W mass to date;; moreover, associated production of pairs of vector bosons have been observed and measured. The precise knowledge of top and W masses is providing decisive new input for the allowed mass range of a standard model Higgs boson, as well as for the parameter space of benchmark scenarios in supersymmetric theories.

We show that the cosmic microwave background (CMB) data of WMAP can give subelectronvolt limit on the neutrino mass. We investigate how much we can make it more stringent by using “standard ruler” measurements such as baryon acoustic oscillation (BAO) and type Ia supernovae (SN).

A time‐dependent bosonic string configuration is discussed, in graviton and dilaton backgrounds, which leads to Weyl‐symmetry beta‐functions which are homogeneous in X0, to any order in α′. As a consequence, a string reparametrization can always be implemented, such that beta functions can be cancelled, to any order in α′. This non‐perturbative conformal invariance is valid for any target space dimension, and leads to a power law expanding Universe, for which the power vanishes if a specific relation between the dimension and dilaton amplitude holds. Finally, D = 4 is the minimum dimension (in the case of a spherical world sheet) for which this configuration is consistent with a Wick rotation in a Minkowski target space.

Two structurally similar versions of an NMOS custom VLSI circuit, fabricated by different manufacturers, have been irradiated with a /sup 60/Co source up to doses of 100 krad. Large differences in their behavior after irradiation have been seen and are thought to be due to the fabrication processes. These differences are observed in test structure measurements and overall chip performance. An increase in circuit noise causes one version of the chip to be unusable after radiation doses of 20 krad. >

Preliminary neutrino oscillation results are presented on data from the MINOS experiment taken up to March 2007, yeilding an exposure of 2.50×1020 protons on target. New values of Δm322 = (2.38−0.16+0.20)×10−3eV2/c4 and sin522θ23 = 1.00−0.08 are obtained.

Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter Facebook Reddit LinkedIn Tools Icon Tools Reprints and Permissions Cite Icon Cite Search Site Citation Y. Verbin; Sigma Model Q‐balls and Q‐Stars. AIP Conf. Proc. 20 November 2007; 957 (1): 275–278. https://doi.org/10.1063/1.2823779 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentAIP Publishing PortfolioAIP Conference Proceedings Search Advanced Search |Citation Search