International Journal of Modern Physics A

We investigate the decays D⁰ → π^-ℓ⁺ν and D⁰ → K^-ℓ⁺ν, where ℓ is e or μ, using approximately 7 fb^-1 of data collected with the CLEO III detector. We find . Fits to the kinematic distributions of the data provide parameters describing the form factor of each mode. Combining the form factor results and R₀ gives .

Using data collected by FOCUS, we present a preliminary measurement for the vector meson semileptonic branching ratio . Using a sample of 397 ± 42 and 11, 811 ± 151 D⁺ → ρ⁰μ⁺ν and events, respectively, we find .

Using data collected by the fixed target Fermilab experiment FOCUS, we present several first measurements for the semileptonic decay . Using a model that includes a S-wave component, we measure the form factor ratios to be r_v = 1.706 ± 0.677 ± 0.342 and r₂ = 0.912 ± 0.370 ± 0.104 and the S-wave amplitude to be A = 0.347 ± 0.222 ± 0.053 GeV^-1. Finally, we measure the vector semileptonic branching ratio .

We present a new measurement of the branching ratio of the Cabibbo suppressed decay D⁰ → π^-μ⁺ν relative to the Cabibbo favored decay D⁰ → K^-μ⁺ν and an improved measurement of the ratio . We also report a new measurement of the q² dependence of the form factors for D⁰ → π^-μ⁺ν and D⁰ → K^-μ⁺ν.

Based on a data sample of 60 pb^-1 collected at the ψ(3770) resonance with the CLEO-c detector at CESR, we present improved measurements of absolute branching fractions for exclusive D⁰ semileptonic decays into K^-e⁺ν, π^-e⁺ν and K*^-e⁺ν, and the first observation and measurement of D⁰ → ρ^-e⁺ν. The determinations of the CKM matrix elements V_cs and V_cd are reviewed.

We report the first measurement of the absolute branching fraction at the ϒ(4S) resonance using data collected with the BABAR detector at the PEP-II asymmetric-energy e⁺e^- storage ring. The analysis is performed with partial reconstruction of the decay , where the presence of a signal decay is determined using only the lepton and the soft pion from the D* decay. By reconstructing events with one or two signal decays, we obtain a preliminary result of . Our result does not depend on branching fractions of the and the D*⁺ decays, on the individual simulated reconstruction efficiencies, on the ratio of the charged and neutral B meson lifetimes, or on the assumption of isospin symmetry.

Recent results on charmonia decays at BES II are reported, including the measurements of ψ(2S) → Vector-Pseudoscalar, ψ(2S) → Vector-Tensor and for a test of the pQCD "12% rule" between ψ(2S) and J/ψ decays; the first observations of χ_c0 → f₀(980)f₀(980), ; and a study of the pentaquark state in ψ(2S) and J/ψ decays.

Using 5.46 pb^-1 of e⁺e^- annihilation data collected at the ψ(2S) with the CLEO detector we have observed a variety of new hadronic decay modes of the ψ(2S). A comprehensive set of branching ratios and upper limits is presented.

Extending a previous analysis¹ the double charmonium production and has been investigated with a data set of 155 fb^-1 with the Belle detector. Theoretical predictions for the cross section are one order of magnitude lower than the measured value and this discrepancy is still not understood. In a very recent update with a dataset of 285 fb^-1 strong evidence for a new charmonium state at a mass of 3.940 GeV was found.

Electromagnetic radiative penguin decays of the B meson were studied with the BABAR detector at SLAC's PEP-II asymmetric-energy B Factory. Branching fractions and isospin asymmetry of the decay B → K*γ, branching fractions of , and a search for B⁰ → ϕγ are presented. The decay rates may be enhanced by contributions from non-standard model processes.

A search for the decays B → ρ(770)γ and B⁰ → ω(782)γ is performed on a sample of 211 million events collected by the BABAR detector at the PEP-II asymmetric-energy e⁺e^- storage ring. No evidence for the decays is seen. We set the following limits on the individual branching fractions , , and at the 90% confidence level (C.L.). We use the quark model to limit the combined branching fraction and constrain |V_td|/|V_ts|.

We report search results for flavor-changing neutral current process b → dγ with a data sample containing 275 million B meson pairs accumulated at ϒ(4S) resonance. We studied the exclusive decays B⁺ → ρ⁺γ, B⁰ → ρ⁰γ and B⁰ → ωγ, and find no significant signal. We set an upper limit for combined branching fraction at 90% confidence level.

Results of a search for the Flavor-Changing Neutral Current decay using collision data at collected at Fermilab Tevatron collider by the CDF and DØ detectors are presented. CDF reports upper limits on and at the 95% C.L. using 171 pb^-1. The DØ Collaboration used 240 pb^-1 to set an even more stringent limit on the branching ratio for of 5.0 · 10^-7 at the 95% C.L.

We present preliminary measurements from a combined analysis of lifetimes and transversity amplitudes for and and present the first direct measurement of the width difference in system using 260 pb^-1 CDF Run II data. For , we obtain , , . The decay amplitudes and lifetime are also measured.

We present the more recent measurements of the B hadrons lifetimes and its ratios, performed using 250 pb^-1 of the Run II data collected with the DØ detector at Tevatron.

We report studies of semileptonic decays, B → X_cℓν, based on a sample of 88 million events recorded with the BABAR detector. We have measured four moments of the electron energy and hadronic mass distributions and determined the inclusive branching fraction, the CKM matrix element |V_cb|, and other heavy quark parameters, using Heavy Quark Expansions in the kinetic mass scheme. In addition, we have studied a large sample of B⁰ → D*^-ℓ⁺ν decays and extracted the decay form factors and |V_cb|.

Decay constants and form factors for parity-even (s-wave) and parity-odd (p-wave) mesons are studied within a covariant light-front approach. The three universal Isgur-Wise functions for heavy-to-heavy meson transitions are obtained.

Lattice Monte Carlo simulations now include the effects of 2 light sea quarks and 1 strange sea quark through the use of an improved staggered fermion action. Consequently, results important to phenomenology are free of the approximate 10% errors inherent in the quenched approximation. This talk reports on calculations of the B and B_s, decay constants and B → πℓν form factors. Accurate determinations of these quantities will lead to tighter constraints on CKM matrix elements.

We construct a valid definition of the k_T-dependent B meson wave function, and then calculate next-to-leading-order corrections. We show that the B meson wave function remains normalizable after taking into account renormalization-group evolution effects, contrary to the observation derived from the collinear factorization theorem.

We present a measurement of the first and second moments of the squared-mass distribution of charm hadrons in semileptonic decays of B mesons based on ~ 180 pb^-1 of data taken with the CDF II detector at the Fermilab Tevatron. For a minimum lepton momentum of 0.7 GeV/c in the B meson rest frame, we measure the first two moments of the D** → D^(*)π component to be and . Combining these values with known contributions from the D and D* components, we obtain the overall charm hadron moments and where is the spin-averaged D meson mass and the subscript "BR" denotes the uncertainty from the branching ratios used to combine the D, D* and D** components. From these moments we also determine the non-perturbative Heavy Quark Effective Theory parameters Λ and λ₁ in the pole and 1S mass schemes.

Using 250 pb^-1 of data collected with the DØ detector in Run II of the Tevatron, the two narrow (L = 1) states, D₁(2420) and have been observed in semileptonic decays of B mesons. Results on the D*⁺ π^- decay mode are presented including a measurement of the branching fraction of B mesons to these states.

Using data collected with the DØ detector in Run II of the Tevatron, we study decays of the B** and meson. For the first time the separation of the specific excited states B₁ and has been observed. In addition, we use the B_c candidates to measure the mass and the lifetime of the B_c.

Based on data collected by the CLEO III detector at CESR, we started a series of investigations to open the mysteries of the ϒ(5S) resonance decay properties. B_s mesons are expected to decay predominantly into D_s meson, while the lighter B mesons decay into D_s only about 10% of the time. We exploit this difference to present the first evidence of a substantial production of B_s mesons at the ϒ(5S) resonance. We make here a preliminary model dependent estimate of the ratio of to the total quark pair production at the ϒ(5S) energy to be (21 ± 3 ± 9)%.

The production of 's from continuum and from B decays is studied using 116 fb^-1 of data collected by the BABAR detector. A measurement of the ratio of the branching fractions of the decaying into Ξ^-π⁺ and Ω^-K⁺ final states is presented.

The SELEX Collaboration has announced the first observation of a massive, narrow resonance in the charm-strange system. Seen both in D_Sη and D⁰K⁺ final states, the meson is unusual both in that it is very narrow despite being far above the strong decay threshold and also in that the . Production is also unusual, with a large asymmetry favoring over production from the Σ^- beam.

We report on a search for the flavor-changing neutral current decays D⁰ → e⁺e^- and D⁰ → μ⁺μ^-, and the lepton-flavor violating decay D⁰ → e^±μ^∓. The measurement is based on 122 fb^-1 of data collected by the BABAR detector at the PEP-II asymmetric e⁺e^- collider. No evidence is found for any of the decays. The upper limits on the branching fractions, at the 90% confidence level, are 1.2 × 10^-6 for D⁰ → e⁺e^-, 1.3 × 10^-6 for D⁰ → μ⁺μ^-, and 8.1 × 10^-7 for D⁰ → e^±μ^∓.

In 60 pb^-1 of data taken on the ψ(3770) resonance with the CLEO-c detector, we find 8 D⁺ → μ⁺ν^- event candidates that are mostly signal, containing only 1 estimated background. Using this statistically compelling sample, we measure the value of , and determine f_D⁺ = (198 ± 41 ± 17) MeV.

Preliminary results are reported for measurements of the masses and widths of the L = 1 charm mesons and , using data from Run II of the Fermilab Tevatron. Final results are presented for CP asymmetry and relative branching fraction for the decays D⁰ → K⁺K^- and π⁺π^-.

Based on an 87-fb^-1 dataset collected by the Babar detector at the PEP-II asymmetric-energy B-Factory, a search for mixing has been made using the semileptonic decay modes D*⁺ → π⁺D⁰, D⁰ → Kev (+c.c.). The use of these modes allows unambiguous flavor tagging and a combined fit of the D⁰ decay time and D*⁺-D⁰ mass difference (ΔM) distributions. The high-statistics sample of unmixed semileptonic D⁰ decays is used to model the ΔM distribution and time-dependence of mixed events directly from the data. Neural networks are used to select events and reconstruct the D⁰. A result consistent with no charm mixing has been obtained, R_mix = 0.0023 ± 0.0012 ± 0.0004. This corresponds to an upper limit of R_mix < 0.0042 (90% CL).

We present an analysis of the decay D⁰ → K⁺π^- from FOCUS. From a sample of 234 events we find a branching ratio of under the assumption of no mixing and no CP violation. We also present limits on charm mixing.

Using data from the FOCUS experiment, we report on the decay of D mesons into states containing more than one . We present evidence for two new Cabibbo favored decay modes, and and measure their combined branching fraction relative to . We also report new measurements of , , , and .

We present a search for the decay B⁺ → τ⁺ν_τ in decays recorded with the BABAR detector at the SLAC PEP-II B-Factory. A sample of events with one reconstructed exclusive semi-leptonic B decay is selected, and in the recoil a search for B⁺ → τ⁺ ν_τ signal is performed. The τ is identified in the following channels: , , , , . We find no evidence of signal, and we set a preliminary upper limit on the branching fraction of at the 90% confidence level (CL). This result is then combined with a statistically independent BABAR search for B⁺ → τ⁺ν_τ to give a combined preliminary limit of at 90% CL.

We report on a study of B mesons decaying into one of the narrow P-wave charm resonances, and D₁(2420)⁰. Our preliminary results are based on 89 million pairs collected with the BABAR detector at the PEP-II asymmetric B Factory. Our study will be useful in the investigation of the properties of Heavy Quark Effective Theory.

Using 57.2 pb^-1 of data collected with the CLEO-c detector at the ψ(3770) resonance, we measure absolute branching fractions for three D⁰ and two D⁺ Cabibbo-allowed hadronic decay modes, and the cross section for at .

We present a study of and D_sJ(2460)⁺ meson production in B decays based on a data sample of 122 million pairs collected with the BABAR experiment.

Measurements of charmless semileptonic B-meson decays and the CKM matrix element |V_ub| are reported based on a sample of 88 million events recorded with the BABAR detector. Decays B → X_uℓν are selected from both tagged and untagged events and separated from the dominant charm background, B → X_cℓν, using different kinematic variables: the lepton momentum E_ℓ, the squared four-momentum transfer q², and the hadronic mass m_X. The extrapolation to the total decay rate to determine |V_ub| is performed for different theoretical models. We have also measured branching ratios for the exclusive semileptonic decays B → π(ρ,ω,η,η′,a₀)ℓν, where a high signal purity is reached by fully or partially reconstructing the second B meson.

We present preliminary results on the branching fractions and , based on a data sample of approximately events collected by the BABAR detector at the PEP-II e⁺e^-B–factory. We reconstruct B⁰ mesons using both a partial and a full reconstruction technique. We obtain the following preliminary results:

Correlations in the azimuthal angle between the two largest transverse momentum jets have been measured using the DØ detector in collisions at . The analysis is based on an inclusive dijet event sample in the central rapidity region corresponding to an integrated luminosity of 150 pb^-1. Azimuthal correlations are stronger at larger transverse momenta. These are well-described in NLO pQCD, except at large azimuthal differences where soft effects are significant.

We present a preliminary measurement of angular correlations between b jets. The distribution of Δϕ between a muon-tagged jet and a lifetime-tagged jet in data is compared to individual distributions for gluon splitting, flavor excitation and flavor creation processes, and background. The relative contributions of gluon splitting, flavor excitation and flavor creation to the data distribution are determined.

We present the results on fragmentation differences of quark and gluon jets obtained by CDF at . We compare the multiplicities and momentum distributions of charged particles in two data samples: dijet data and photon+jet data. These two samples have a different quark/gluon jet content, which allows a measurement of the inclusive properties of gluon and quark jets. The results are compared to the earlier measurements obtained at e+e- collisions and to the re-summed perturbative QCD calculations.

I discuss general unified formulas for resumming collinear and soft contributions to QCD hard scattering cross sections at large x. Expansions of the resummed cross sections to next-to-next-to-next-to-leading order are also shown along with applications of the formalism.

As it is well known, large threshold logarithmic contributions can be resummed in the form factors within a fixed order approximation. Such form factors, however, are divergent at large x, as a consequence of the QCD coupling hitting the Landau pole in the resumming procedure. A possible solution is presented here, and it requires using an effective coupling which takes into account additional –usually neglected– absorptive physical effects; as a consequence, the theory becomes completely predictive with regular form factors at large x. These results are pertinent to a wide class of phenomenological applications, and in particular are of interest for processes at the B meson mass scale.

I discuss recent progress in large-N_C inspired determinations of chiral low energy constants of order p⁶. I illustrate the general method and then describe how it works in the case of the 〈VAP〉 three-point function.

With an eye toward LHC processes in which theoretical precisions of 1% are desired, we introduce the theory of the simultaneous YFS resummation of QED and QCD to compute the size of the expected resummed soft radiative threshold effects in precision studies of heavy particle production at the LHC. Our results show that both QED and QCD soft threshold effects must be controlled to be on the conservative side to achieve such precision goals.

Strong and weak decays of pentaquarks are studied in the framework of the light-front approach.

Recently the H1 Collaboration observed a narrow peak in D*^-p invariant mass spectrum from what is believed to be an anti-charmed pentaquark baryon state with quark content, produced in deep inelastic scattering in ep collisions at HERA. This new state was tentatively named as being an anti-charmed analog of Θ⁺ pentaquark discovered in 2003 by LEPS Collaboration. The upgraded CDF detector is sensitive to production of charmed pentaquark states in central rapidity region due to ability to trigger on displaced tracks from weakly decaying daughter hadrons. At this conference we report results of searches for anti-charmed pentaquark and its charged isospin partner in collisions at at Tevatron.

We find no evidence for high-energy photoproduction of pentaquarks at 1540 MeV/c², 1862 MeV/c², or 3099 MeV/c² using decay modes , Ξ^-π^-, and D^(*)-p, respectively.

A study of the decay is performed using 81 fb^-1 of data collected at the ϒ(4S) with the BABAR detector at PEP-II. The branching fraction of is measured to be (6.7 ± 0.9 ± 0.6) × 10⁶. An upper limit on the branching fraction of , where Θ*⁺⁺ is a narrow state decaying to pK⁺, is set to be 1.5 × 10^-7 for 1.43 < m(Θ*⁺⁺) < 1.85 GeV/c² at 90% confidence level. All results are preliminary.

We predict the shape of the transverse momentum p_T spectrum of ϒ production. The distribution at low p_T is dominated by the region of small impact parameter b and may be computed reliably in perturbation theory. We resum to all orders in the strong coupling α_s the process-independent large logarithmic contributions that arise from initial-state gluon showers in the small p_T(≤ M_ϒ) region. The cross section at large p_T is represented by the lowest-order non-vanishing perturbative contribution.

Measurements of the production of high-p_T direct photons by a 515 GeV/c π^- beam and 530 and 800 GeV/c proton beams in interactions with Be and H₂ targets are presented. The data span the kinematic ranges of 3.5 < p_T < 12 GeV/c in transverse momentum and 1.5 units in rapidity. The inclusive direct-photon cross sections are compared with NLO pQCD calculations and expectations based on a phenomenological parton-k_T model.

The NuTeV experiment obtained high statistics samples of neutrino and antineutrino charged current events during the 1996-1997 Fermilab fixed target run. The experiment combines sign-selected neutrino and antineutrino beams and the upgraded CCFR iron-scintillator neutrino detector. A precision continuous calibration beam was used to determine the muon and hadron energy scales to a precision of 0.7% and 0.43% respectively. The structure functions F₂(x, Q²) and xF₃(x, Q²) obtained by fitting the y-dependence of the sum and the difference of the ν and differential cross sections are presented.

The Forward Proton Detector (FPD) is a new sub-system of the DØ detector implemented for Run II at the Fermilab Tevatron which gives access to a wide range of diffractive scattering physics processes. This new detector is described and preliminary results from the diffractive program are presented.

Last year's X(3872) discovery was confirmed with the CDF II detector in collisions. We measure its mass to be 3871.3±0.7±0.4 MeV/c². The source of X-mesons in the large CDF sample is resolved by studying their vertex displacement. We find 16.1±4.9±2.0% of our X-sample comes from decays of b-hadrons, and the remainder from prompt sources: either direct production or by decay of (unknown) short-lived particles. The mix of production sources is similar to that observed for the ψ(2S) charmonium state.

We report measurements of B decay modes involving the newly discovered D_sJ and X(3872) particles. Possible spin-parity and quark content assignments of these new states are discussed. The results are based on a large data sample recorded by the Belle detector at the KEKB e⁺e^- collider.

In my talk I discussed the properties of the newly discovered , D_sJ(2460), X(3872), and SELEX states and suggested experimental measurements that can shed light on them. In this writeup I concentrate on an important facet of under-standing the D_sJ states, the properties of the closely related and D′₁ states. These states are well described as the broad, j = 1/2 non-strange charmed P-wave mesons.

We examine to what extent several recently discovered narrow resonances can be interpreted as conventional bound states describable using a potential model. In doing so, we use a semirelativistic approach, which includes both the v²/c² and QCD one-loop corrections to the short distance potential and a long range linear potential together with its scalar and vector v²/c² spin-dependent terms.

The status of RHIC theory and phenomenology is reviewed with an emphasis on the indications for the creation of a new deconfined state of matter. The critical role of high energy nuclear physics in the development of theoretical tools that address various aspects of the QCD many body dynamics is highlighted. The perspectives for studying nuclear matter under even more extreme conditions at the LHC and the overlap with high energy physics is discussed.

The combination of the ionization energy loss (dE/dx) from Time Projection Chamber (TPC) at ≃ 8% resolution and multi-gap resistive plate chamber time-of-flight (TOF) at 85ps provides powerful particle identification. We present spectra of identified charged pions from transverse momentum p_T≃0.2 GeV/c to 7-8 GeV/c in Au+Au collisions at . Physics implications will be discussed.

We briefly review the nonequilibrium description of parton thermalization then extend the formulation to account for contributions to fluctuations from flow and the energy loss of the high transverse momentum particles. Calculations are then compared to the measured ransverse momentum fluctuations.

Recent performance of Fermilab's Tevatron has exceeded this year's design goals and further accelerator upgrades are underway. The high-luminosity period which follows these improvements is known as Run IIb. The DØ experiment is in the midst of a comprehensive upgrade program designed to enable it to thrive with much higher data rate and occupancy. Extensive modifications of and additions to all levels of the trigger and the silicon tracker are in progress. All upgrade projects are on schedule for installation in the 2005 shutdown.

The DØ trigger system has been upgraded for Run II at the Tevatron. I present the current status of the DØ trigger.

At BABAR, the Level 1 Drift Chamber trigger is being upgraded to reduce increasing background rates while the PEP-II luminosity keeps improving. This upgrade uses the drift time information and stereo wires in the drift chamber to perform a 3D track reconstruction that effectively rejects background events spread out along the beam line.

We have developed two radiation-hard ASICs for optical data transmission in the ATLAS pixel detector at the CERN Large Hadron Collider (LHC): a driver chip for a Vertical Cavity Surface Emitting Laser (VCSEL) diode for 80 Mbit/s data transmission from the detector, and a Bi-Phase Mark decoder chip to recover the control data and 40 MHz clock which is received optically by a PIN diode on the detector side. We present comprehensive results from the final design and from irradiation studies of both circuits with 24 GeV protons up to a total dose of 62 Mrad.

We have designed a hybrid board for optical data transmission in the ATLAS pixel detector. This opto-board features two kinds of ASICs, VDC and DORIC. The former drives a Vertical Cavity Surface Emitting Laser (VCSEL) for data transmission from the pixel detector and the latter recovers Bi-Phase Mark (BPM) encoded command signals received optically by a PIN diode. The opto-board is fabricated with a beryllium-oxide (BeO) substrate for heat management. We present the status of opto-board production and performance.

The innermost layer of the Belle silicon vertex detector operates 1.5 cm away from the collision point of the highest luminosity collider in the world. Occupancy in this innermost layer is already 10% and expected to continue increasing with the planned significant luminosity increases. A pair of prototype detectors has been developed to address this problem, based upon the same CMOS camera technology now widely deployed in low-cost consumer devices such as cellular telephones. Problems unique to operating in a high luminosity B-factory environment are discussed. Results from a number of tests are presented, demonstrating the viability of this detector technology.

A new silicon detector was designed by the CDF collaboration for Run IIb of the Tevatron at Fermilab. The main building block of the new detector is a "supermodule" or "stave", an innovative, compact and lightweight structure of several readout hybrids and sensors with a bus cable running directly underneath the sensors to carry power, data, and control signals to and from the hybrids. The hybrids use a new, radiation-hard readout chip, the SVX4 chip. A number of SVX4 chips, readout hybrids, sensors, and supermodules were produced and tested in preproduction. The performance (including radiation-hardness) and yield of these components met or exceeded all design goals. The detector design goals, solutions, and performance results are presented.

The provision of intense stored muon beams would allow the properties of neutrinos to be measured precisely and provide a route to multi-TeV lepton-anti-lepton collisions. The short muon lifetime makes it impossible to employ traditional cooling techniques while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the proposed cooling technique. The international Muon Ionisation Cooling Experiment (MICE) collaboration has been approved at the Rutherford Appleton Laboratory and proposes to perform an engineering demonstration of ionisation cooling. The MICE experiment will require the measurement of the momentum and position of muons entering and leaving a section of ionisation cooling channel with high precision and purity in the presence of a large background. The technology chosen to meet this challenge is scintillating fibres readout with Visible Light Photon Detectors. The design, construction and operation of a prototype detector is described, as well as a summary of ongoing research and development activities in preparation for supplying the trackers needed for the MICE experiment.

We report on the development of a large Time Projection Chamber (TPC) for the e⁺e^- Linear Collider (LC). Our studies concentrate on the use of Gas Electron Multiplier (GEM) foils for the gas amplification in the TPC. Charge transfer measurements are performed using a triple-GEM structure installed into a small test chamber which is irradiated with an ⁵⁵Fe source. This device is operated in high magnetic fields up to 5 T. No severe drop in primary ionisation statistics is observed, but an improved suppression of ion backdrift is achieved. For optimum settings the relative ion backdrift drops to only 2 per mil. Additionally, the width of the charge cloud created by individual ⁵⁵Fe photons is measured using a finely segmented strip readout behind the triple GEM structure. Charge widths between 0.2 and 0.5 mm RMS are observed. This charge broadening is reduced in high magnetic fields. Based on these experiments a prototype GEM-TPC has been constructed for further tests in the 5 T magnet and in test beams.

The Compact Muon Solenoid (CMS) experiment is a general-purpose detector designed to explore the physics of proton-proton collisions at a centre-of-mass energy of 14 TeV over the full range of luminosities expected at the Large Hadron Collider (LHC). The Electromagnetic Calorimeter (ECAL) will play an essential role in the study of the electroweak symmetry breaking, particularly through the exploration of the Higgs boson sector. To evaluate its characteristics, an ECAL prototype was placed in an electron testbeam at CERN. Highlights of results obtained during the test beam campaign are presented.

Crystals are used as a homogeneous calorimetric medium in many high-energy physics experiments. For some experiments, performance has to be ensured in very difficult operating conditions, like a high radiation environment, very large particle fluxes, high collision rates, placing constraints on response and readout time. An overview is presented of recent achievements in the field, with particular attention given to the performance of Lead Tungstate (PWO) crystals exposed to high particle fluxes.

We report on the development of a digital hadron calorimeter for the future International Linear Collider. Te calorimeter is of the sandwich type with iron absorber plates and resistive plate chamber as active medium. The readout pads are very finely segmented, with an area of 1 cm², and are being read out digitally. We present the design, construction and testing of various prototype chambers as well as the development of a readout system capable of handling a large number of channels. We plan to construct a 1 m³ prototype section of the calorimeter containing approximately 400,000 channels. The section will undergo testing in various particle beams.

The new barrel Instrumented Flux Return (IFR) of BABAR detector will be reported here. Limited Stramer Tubes (LSTs) have been chosen to replace the existing RPCs as active elements of the barrel IFR. The layout of the new detector will be discussed: in particular, a cell bigger than the standard one has been used to improve efficiency and reliability. The extruded profile is coated with a resistive layer of graphite having a typical surface resistivity between 0.2 and 0.4 MOhm/square. The tubes are assembled in modules and installed in 12 active layers of each sextant of the IFR detector. R&D studies which have been done to choose the final design will be discussed, as well as the Quality Control procedure adopted during the tube production to assure high performances of the detector.

The requirements for a linear collider muon detector are discussed and a solution is presented based on solid scintillating strips with embedded wavelength shifting optical fibers. Multi-anode photo-multiplier tubes are a good candidate for photon detection. Their single photo-electron response can be calibrated using fast pulses from light-emitting diodes.

Muon storage rings have been proposed for use as sources of intense high-energy neutrino beams and as the basis for multi-TeV lepton-antilepton colliding beam facilities. To optimise the performance of such facilities is likely to require the phase-space compression (cooling) of the muon beam prior to acceleration and storage. The short muon-lifetime makes it impossible to employ traditional techniques to cool the beam while maintaining the muon-beam intensity. Ionisation cooling, a process in which the muon beam is passed through a series of liquid hydrogen absorbers followed by accelerating RF-cavities, is the technique proposed to cool the muon beam. The international Muon Ionisation Cooling Experiment (MICE) collaboration has been formed to carry out a muon-cooling demonstration experiment, and its proposal to Rutherford Appleton Laboratory has been approved. The MICE cooling channel, the instrumentation and the implementation at the Rutherford Appleton Laboratory is described together with the predicted performance of the channel and the measurements that will be made.

The continuing LH2 R & D by the MuCool group, conducted by Illinois Consortium for Accelerator Research (ICAR) institutions (NIU, IIT and UIUC), the University of Mississippi, Oxford University and Fermilab, are summarized here, including results for the first hydrogen tests of an absorber prototype from Osaka University and KEK cooled by internal convection at the newly constructed FNAL MuCool Test Area (MTA). The program includes designs for the high-powered test of an absorber prototype (external heat exchange) at the MTA which are nearing completion to be installed by fall 2005, an alternative absorber design (internal heat exchange) being finalized for the approved cooling experiment (MICE) at Rutherford-Appleton Laboratory, and a novel idea for gaseous hydrogen absorbers being developed at Fermilab for a high powered test at the MTA in 2006.

Progress on six dimensional ionization muon cooling with relatively small rings of magnets is described. Lattices being explored include scaling sector cyclotrons with edge focusing and strong focusing, fixed field alternating gradient (FFAG) rings. Ionization cooling is provided by high pressure hydrogen gas which removes both transverse and longitudinal momentum. Lost longitudinal momentum is replaced using radio frequency (RF) cavities, giving a net transverse emittance reduction. The longer path length in the hydrogen of higher momentum muons decreases longitudinal emittance at the expense of transverse emittance. Thus emittance exchange allows these rings to cool in all six dimensions and not just transversely. Alternatively, if the RF is located after the ring, it may be possible to cool the muons by stopping them as they spiral adiabatically into a central swarm. As p → 0, Δp → 0. The resulting cooled muons can lead to an intense muon beam which could be a source for neutrino factories or muon colliders.

We discuss particle tracking simulations in a storage ring with Lithium lens inserts designed for the transverse phase space cooling of muons by the ionization cooling. In a hard-edged magnetic element model, we demonstrate the equilibrium normalized transverse emittance of 0.3 mm*rad which is necessary for a Higgs Factory, a low energy mu+mu- Collider. For the 6 dimensional phase space cooling of muons, a method of using bent Lithium lenses were discussed.

Given their 2.2 μs lifetime, muons must be accelerated fairly rapidly for a neutrino factory or muon collider. Muon bunches tend to be large. Progress in fixed field, alternating gradient (FFAG) lattices to meet these challenges are reviewed. FFAG magnets are naturally wide; low momentum muons move from the low field side of a gradient magnet to the high field side as they gain energy. This can be exploited to do double duty and allow a large beam admittance without unduly increasing the magnetic field volume. If the amount of RF must be reduced to optimize cost, an FFAG ring can accommodate extra orbits. I describe scaling FFAGs in which the bends in each magnet are energy independent and non-scaling FFAGs in which the bends in each magnet do vary with muon energy. In all FFAG designs the sum of the bends in groups of magnets are constant; otherwise orbits would not close. Ways of keeping the accelerating beam in phase with the RF are described. Finally, a 1 MeV proof of principle scaling FFAG has been built at KEK and began accelerating protons in June 2000 with a 1 kHz repetition rate.

The BaBar experiment is currently operating near the rate limit of its ability to log event data to disk and tape using the existing hardware and software systems. Consequently we have chosen to design and implement a new system for logging event data. The new system is designed to be scalable, so that the data rate can be increased by adding systems at one of three levels. It also has the property that data can be logged at almost unlimited burst rates without introducing dead time. The key to these features lies in the use of many nodes within the level three trigger system of BaBar. This allows the events to first be logged to local disks within the trigger system, and then later to be merged to any of multiple merge servers in non-real-time.

We discuss the new CLEO-c EventStore: a pluggable system that scales from personal needs up to collaboration-wide managed data. Its indexing and versioning features allow physicists to quickly access raw, reconstructed and MC data. It does simple bookkeeping of desired datasets and guarantees the reproducibility of various details of physics analysis. A wide range of physics queries and a variety of file formats are supported.

Each new generation of collider experiments confronts the challenge of delivering an event store having at least the performance and functionality of current-generation stores, in the presence of an order of magnitude more data and new computing paradigms (object orientation just a few years ago; grid and service-based computing today). The ATLAS experiment at the Large Hadron Collider, for example, will produce 1.6-megabyte events at 200 Hz–an annual raw data volume of 3.2 petabytes. With derived and simulated data, the total volume may approach 10 petabytes per year.

Scale, however, is not the only challenge. In the Large Hadron Collider (LHC) experiments, the preponderance of computing power will come from outside the host laboratory. More significantly, no single site will host a complete copy of the event store–data will be distributed, not simply replicated for convenience, and many physics analyses will routinely require distributed (grid) computing.

This paper uses the emerging ATLAS computing model to provide a glimpse of how next-generation event stores are taking shape, touching on key issues in navigation, distribution, scale, coherence, data models and representation, metadata infrastructure, and the role(s) of databases in event store management.

The DØ experiment at Fermilab's Tevatron will record several petabytes of data over the next five years in pursuing the goals of understanding nature and searching for the origin of mass. Computing resources required to analyze these data far exceed capabilities of any one institution. Moreover, the widely scattered geographical distribution of DØ collaborators poses further serious difficulties for optimal use of human and computing resources. These difficulties will exacerbate in future high energy physics experiments, like the LHC. The computing grid has long been recognized as a solution to these problems. This technology is being made a more immediate reality to end users in DØ by developing a grid in the DØ Southern Analysis Region (DØSAR), DØSAR-Grid, using all available resources within it and a home-grown local task manager, McFarm. We will present the architecture in which the DØSAR-Grid is implemented, the use of technology and the functionality of the grid, and the experience from operating the grid in simulation, reprocessing and data analyses for a currently running HEP experiment.

HEP collaborations are deploying grid technologies to address petabyte-scale data processing challenges. In addition to file-based event data, HEP data processing requires access to terabytes of non-event data (detector conditions, calibrations, etc.) stored in relational databases. Inadequate for non-event data delivery in these amounts, database access control technologies for grid computing are limited to encrypted message transfers. To overcome these database access limitations one must go beyond the existing grid infrastructure. A proposed hyperinfrastructure of distributed database services implements efficient secure data access methods. We introduce several technologies laying a foundation of a new hyperinfrastructure. We present efficient secure data transfer methods and secure grid query engine technologies federating heterogeneous databases. Lessons learned in a production environment of ATLAS Data Challenges are presented.

The DØ experiment faces many challenges in terms of enabling access to large datasets for physicists on four continents. The strategy for solving these problems on worldwide distributed computing clusters is presented. Since the beginning of Run II of the Tevatron (March 2001) all Monte-Carlo simulations for the experiment have been produced at remote systems. For data analysis, a system of regional analysis centers (RACs) was established which supply the associated institutes with the data. This structure, which is similar to the tiered structure foreseen for the LHC was used in Fall 2003 to reprocess all DØ data with a much improved version of the reconstruction software. This makes DØ the first running experiment that has implemented and operated all important computing tasks of a high energy physics experiment on systems distributed worldwide.

Novel String Banana Template Method (SBTM) for track reconstruction in high multiplicity events in non-uniform magnetic field spectrometer with emphasis on the lowest momenta tracks with significant Multiple Scattering (MS) is described. Two steps model of track with additional parameter/s which takes into account MS for this particular track is introduced. SBTM is time efficient and demonstrates better resolutions than another method equivalent to the Least Squares method (LSM).

The Muon Spectrometer of the ATLAS experiment is a large and complex system relying on several detector technologies. The simulation and reconstruction of muon events require a very careful description of these detectors, some of which provide a muon trigger while the others make precision measurements of tracks. A precise description of the passive materials, toroidal magnet systems and shield is also needed to account for Coulomb scattering and energy losses. Finally, the spectrometer performance is enhanced by the alignment of its precision chambers, so the detector description model must fully implement misalignments and deformations. We present the Detector Description chain employed in the Muon system and its integration in the ATLAS software framework. It relies on a database technology and a standard set of geometrical primitives common to all ATLAS subsystems. The Muon Detector Description has been used successfully in the context of the ATLAS Data Challenges, where it provides a unique and coherent geometry source for the simulation and reconstruction algorithms. It has also been validated in the context of the experimental program of the ATLAS testbeams, where analyses of the treatment of chamber alignment in track reconstruction relies crucially upon the detector description model.

A key feature of collaboration in science and software development is to have a log of what and how is being done - for private use and reuse and for sharing selected parts with collaborators, which most often today are distributed geographically on an ever larger scale. Even better if this log is automatic, created on the fly while a scientist or software developer is working in a habitual way, without the need for extra efforts. The CAVES and CODESH projects address this problem in a novel way, building on the concepts of virtual state and virtual transition to provide an automatic persistent logbook for sessions of data analysis or software development in a collaborating group. A repository of sessions can be configured dynamically to record and make available the knowledge accumulated in the course of a scientific or software endeavor. Access can be controlled to define logbooks of private sessions and sessions shared within or between collaborating groups.

The Klein Gordon equation–which describes mesons–can be reformulated to suit students who have no calculus background. The method is arrived at from a review and a reinterpretation of the mechanics of small oscillations. It may serve as a model for the design of new instructions for other areas of particle physics.