Physics at BABAR

The BABAR detector at the SLAC PEP-II asymmetric e+e- collider has first started collecting data in May 1999. A study of time-dependent CP-violating asymmetries in B0 --> J/psi K0S and B0 --> psi(2S) K0S decays has been performed on a data sample of 9.0fb-1 taken at the Y(4S) resonance and 0.8fb-1 off-resonance, collected through July 2000. The preliminary result sin2beta = 0.12+/-0.37 (stat) +/- 0.09 (syst) is presented here, together with preliminary results on neutral and charged B meson lifetimes and B0B0bar mixing.Comment: 14 pages, 8 figures (in 12 eps files), 5 tables, submitted to RADCOR-2000, Carmel, September 11-15, 200

A Novel Manufacturing Process for Glass THGEMs and First Characterisation in an Optical Gaseous Argon TPC

This paper details a novel, patent pending, abrasive machining manufacturing process for the formation of sub-millimetre holes in THGEMs, with the intended application in gaseous and dual-phase TPCs. Abrasive machining favours a non-ductile substrate such as glasses or ceramics. This innovative manufacturing process allows for unprecedented versatility in THGEM substrates, electrodes, and hole geometry and pattern. Consequently, THGEMs produced via abrasive machining can be tailored for specific properties, for example: high stiffness, low total thickness variation, radiopurity, moisture absorption/outgassing and/or carbonisation resistance. This paper specifically focuses on three glass substrate THGEMs (G-THGEMs) made from Schott Borofloat 33 and Fused Silica. Circular and hexagonal hole shapes are also investigated. The G-THGEM electrodes are made from Indium Tin Oxide (ITO), with a resistivity of 150 $\Omega$/Sq. All G-THGEMs were characterised in an optical (EMCCD) readout GArTPC, and compared to a traditionally manufactured FR4 THGEM, with their charging and secondary scintillation (S2) light production behaviour analysed

Optical Readout of the ARIADNE LArTPC using a Timepix3-based Camera

The ARIADNE Experiment, utilising a 1-ton dual-phase Liquid Argon Time Projection Chamber (LArTPC), aims to develop and mature optical readout technology for large scale LAr detectors. This paper describes the characterisation, using cosmic muons, of a Timepix3-based camera mounted on the ARIADNE detector. The raw data from the camera are natively 3D and zero suppressed, allowing for straightforward event reconstruction, and a gallery of reconstructed LAr interaction events is presented. Taking advantage of the 1.6 ns time resolution of the readout, the drift velocity of the ionised electrons in LAr was determined to be 1.608 \pm 0.005 mm/{\mu}s at 0.54 kV/cm. Energy calibration and resolution were determined using through-going muons. The energy resolution was found to be approximately 11 % for the presented dataset. A preliminary study of the energy deposition (dE/dx) as a function of distance has also been performed for two stopping muon events, and comparison to GEANT4 simulation shows good agreement. The results presented demonstrate the capabilities of this technology, and its application is discussed in the context of the future kiloton-scale dual-phase LAr detectors that will be used in the DUNE programme

ARIADNE+: Large scale demonstration of fast optical readout for dual-phase LArTPCs at the CERN Neutrino Platform

Optical readout of large scale dual-phase liquid Argon TPCs is an attractive alternative to charge readout and has been successfully demonstrated on a 2x2m active region within the CERN protoDUNE cold box. ARIADNE+ uses four Timepix3 cameras imaging the S2 light produced by 16 novel, patent pending, glass THGEMs. ARIADNE+ takes advantage of the raw Timepix3 data coming natively 3D and zero suppressed with a 1.6ns timing resolution. Three of the four THGEM quadrants implement readout in the visible light range through wavelength shifting, with the fourth featuring a VUV light intensifier, thus removing the need for wavelength shifting altogether. Cosmic ray reconstruction and energy calibration was performed. Presented is a summary of the detector setup and experimental run, preliminary analysis of the run data and future outlook for the ARIADNE program.Comment: Proceedings for NuFACT202

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

Research and Development for Near Detector Systems Towards Long Term Evolution of Ultra-precise Long-baseline Neutrino Experiments

With the discovery of non-zero value of $\theta_{13}$ mixing angle, the next generation of long-baseline neutrino (LBN) experiments offers the possibility of obtaining statistically significant samples of muon and electron neutrinos and anti-neutrinos with large oscillation effects. In this document we intend to highlight the importance of Near Detector facilities in LBN experiments to both constrain the systematic uncertainties affecting oscillation analyses but also to perform, thanks to their close location, measurements of broad benefit for LBN physics goals. A strong European contribution to these efforts is possible

Observation of CP violation in the B 0 system

(for the BABAR Collaboration) The BABAR detector, operating at energies near the Υ(4S) resonance at the PEP-II asymmetric B Factory at SLAC, has collected a sample of 32 million BB pairs by May 2001. A study of timedependent CP-violating asymmetries in events where one neutral B meson is fully reconstructed in a final state containing charmonium has resulted in the measurement sin2β = 0.59 ± 0.14 (stat) ± 0.05 (syst), which establishes CP violation in the B 0 meson system at the 4σ level. B lifetime and mixing measurements from a sub-sample of 23 million BB pairs are also presented. Invited talk presented at the International Europhysics Conference on HEP (HEP2001

Physics at Babar

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