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All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

From CRID to DIRC

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Va'vra, J.↗
DOE OSTI2024

Construction of a Cosmic Ray Telescope for the hpDIRC Radiators at the Electron Ion Collider

Nuclear physics pertains to the understanding of the structure and dynamics of the nuclei of atoms, accounting for almost all of the visible matter in the universe. The future Electron-Ion Collider (EIC) will play a crucial role in discovering new laws of Nuclear physics. A pivotal aspect of the EIC is exceptional particle identification (PID). Identifying charged hadrons in their final state can be done with special types of Cherenkov Detectors. One type of detector utilizes the Detection of Internally Reflected Cherenkov radiation (DIRC) phenomena. Able to provide precise PID separation up to relatively high momenta, DIRC radiators, made of synthetic fused silica, produce Cherenkov radiation when hit by high energy electromagnetically charged particles. In this thesis we present details of the construction of a cosmic ray telescope (CRT) to utilize high energy muons from cosmic rays to test DIRC radiators. These types of radiators will be used for the high-performance DIRC (hpDIRC) to be used in the ePIC detector in the future EIC. We go into detail on the DIRC process and the individual pieces of hardware required to make the CRT. Lots of labor was used for certain parts of the CRT, specifically the construction of a dark box for the DIRC radiators. The CRT construction and implementation of all of its components are planned to be completed before 2025.

Shankman, Nathan↗
DOE OSTI2012

Measurement of the D - s Decay Constant f Ds and Observation of New Charm Resonances Decaying to D*π

The absolute branching fractions for the decays D - s → ℓ-$\bar{v}$ - (ℓ = e, μ, or τ) are measured using a data sample corresponding to an integrated luminosity of 521 fb -1 collected at center of mass energies near 10.58 GeV with the BABAR detector at the PEPII e + e - collider at SLAC. The number of D s - mesons is determined by reconstructing the recoiling system DKXγ in events of the type e + e - → DKXD* s - , where D* s - → D s - γ and X represents additional pions from fragmentation. The D s - → ℓ - v ℓ events are detected by full or partial reconstruction of the recoiling system DKX{gamma}ℓ. The following results are obtained: β(D s - → μ - v) = (6.02 ± 0.38 ± 0.34) x 10 -3 , {Beta}(D s - → τ - v) = (5.00 ± 0.35 ± 0.49) x 10 -2 , and B(D s - → e - ν) < 2.8 x 10 -4 at 90% C.L., where the first uncertainty is statistical and the second is systematic. The branching fraction measurements are combined to determine the D s - decay constant f Ds = (258.6 ± 6.4 ± 7.5) MeV. In addition, a study has been performed of the D + π} - , D 0 π} + , and D* + π - systems in inclusive e + e - → c c interactions in a search for excited D meson states. The dataset used consists of {approx}454 fb -1 . The mass spectra for these systems show, for the first time, candidates for the radial excitations of the D 0 , D* 0 , and D* + , as well as the L = 2 excited states of the D 0 and D - , where L is the orbital angular momentum of the quarks. Finally, a prototype of a next generation Detector of Internally Reflected Cherenkov radiation (Focusing DIRC) has been tested using a 10 GeV electron beam at SLAC. The Focusing DIRC is based on the DIRC which was used in the BABAR detector, but has new pixel photon detectors which improve the resolution on the single photon time of propagation by about an order of magnitude allowing, for the first time, to correct the chromatic smearing in the Cherenkov angle. The Focusing DIRC may be used in a future Super-B factory.

43 PARTICLE ACCELERATORS↗