Measurement of the γ * γ * → η ′ transition form factor
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Engineering topics
Li, Y.
Publications and source records attributed to Li, Y..
Technical supplement to “Polarization transfer observables in elastic electron-proton scattering at Q 2 = 2 . 5 , 5 . 2 , 6 . 8 and 8 . 5 GeV 2 ”
Here, this technical note provides supplemental material for the archival publication of the measure- ments of polarization transfer observables in elastic e → p → e→p scattering from the GEp-III and GEp-2γ experiments in Jefferson Lab's Hall C.
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
Characterization of the Mid-Frequency Arrays for Advanced ACTPol
The Advanced ACTPol upgrade on the Atacama Cosmology Telescope aims to improve the measurement of the cosmic microwave background anisotropies and polarization, using four new dichroic detector arrays fabricated on 150-mm silicon wafers. These bolometric cameras use AlMn transition-edge sensors, coupled to feedhorns with orthomode transducers for polarization sensitivity. The first deployed camera is sensitive to both 150 and 230 GHz. Here, we present the laboratory characterization of the thermal parameters and optical efficiencies for the two newest fielded arrays, each sensitive to both 90 and 150 GHz. We provide assessments of the parameter uniformity across each array with evaluation of systematic uncertainties. Lastly, we show the arrays’ initial performance in the field.
42 ENGINEERING↗
Search for the decay mode B 0 → p p p ¯ p ¯
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Measurement of η c ( 1 S ) , η c ( 2 S ) , and nonresonant η ′ π + π − production via two-photon collisions
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Tuning the activity/stability balance of anion doped CoS Se2- dichalcogenides
Not provided.
08 HYDROGEN↗
Revealing a structural transition in typical Fe-based glass-forming alloy melts
Not Available
Dong, B. S.↗
The CBETA Fractional Arc Test
As part of this development effort, the Cornell-BNL Energy recovery linac Test Accelerator (CBETA) [3], a 4-pass, 150 MeV energy recovery linac (ERL), utilizing a Non-scaling Fixed Field Alternating-gradient (NS-FFA) permanent magnet return loop, is currently under design and construction at Cornell University through the joint collaboration of Brookhaven National Lab (BNL) and the Cornell Laboratory for Accelerator based Sciences and Education (CLASSE). Building on the significant advancements in high-brightness photoelectron sources and SRF technology at Cornell, as well as the FFA magnet and lattice design expertise from BNL, CBETA will establish the operation of a multi-turn SRF based ERL utilizing a compact FFA return loop with large energy acceptance (a factor of roughly 3.6 in energy), and thus demonstrate one possible cost-reduction technology under consideration for the eRHIC design. Moreover, successful completion of the CBETA project requires the study and measurement of many critical phenomena relevant to designing the EIC: the Beam-Breakup (BBU) instability, halo-development and collimation, growth in energy spread from Coherent Synchrotron Radiation (CSR), and CSR micro bunching, and thus should provide valuable insight to the EIC and ERL communities. In order to demonstrate the viability of the CBETA design, the Fractional Arc Test (FAT) was added to the CBETA commissioning sequence.
43 PARTICLE ACCELERATORS↗
CBETA Technical Report (CBETA Note #31)
This document includes twelve sections related to the previous Fractional Arc Test (FAT), CBETA final installation plan has which follows the milestones signed in the contract with the New York State Energy Development Authority (NYSERDA). In the second part we provide a plan for final installation, hardware and software preparation and the beam commissioning.
43 PARTICLE ACCELERATORS↗
Semi‐dominant mutation in the cysteine‐rich receptor‐like kinase gene, ALS 1 , conducts constitutive defence response in rice
Abstract Plants have evolved a sophisticated two‐branch defence system to prevent the growth and spread of pathogen infection. The novel Cys‐rich repeat ( CRR ) containing receptor‐like kinases, known as CRK s, were reported to mediate defence resistance in plants. For rice, there are only two reports of CRK s. A semi‐dominant lesion mimic mutant als1 (apoptosis leaf and sheath 1) in rice was identified to demonstrate spontaneous lesions on the leaf blade and sheath. A map‐based cloning strategy was used for fine mapping and cloning of ALS 1 , which was confirmed to be a typical CRK in rice. Functional studies of ALS 1 were conducted, including phylogenetic analysis, expression analysis, subcellular location and blast resistance identification. Most pathogenesis‐related ( PR ) genes and other defence‐related genes were activated and up‐regulated to a high degree. ALS 1 was expressed mainly in the leaf blade and sheath, in which further study revealed that ALS 1 was present in the vascular bundles. ALS 1 was located in the cell membrane of rice protoplasts, and its mutation did not change its subcellular location. Jasmonic acid ( JA ) and salicylic acid ( SA ) accumulation were observed in als1 , and enhanced blast resistance was also observed. The mutation of ALS 1 caused a constitutively activated defence response in als1 . The results of our study imply that ALS 1 participates in a defence response resembling the common SA ‐, JA ‐ and NH 1 ‐mediated defence responses in rice.
Du, D.↗
Electronic Structures, Magnetic Properties and Half-Metallicity of Heusler Compounds Hf{sub 2}VZ (Z = Ga, In, Tl, Si, Ge, Sn and Pb): First-Principle Calculations
We investigate the electronic structures, magnetic properties and half-metallicity of Heusler compounds Hf{sub 2}VZ (Z = Ga, In, Tl, Si, Ge, Sn and Pb) with Hg{sub 2}CuTi-type structure by using the first-principle calculations based on density-functional theory. It is found that the equilibrium lattice constants of Hf{sub 2}VZ (Z = Ga, In, Tl, Si, Ge, Sn and Pb) compounds are 6.68, 6.88, 6.91, 6.57, 6.63, 6.85 and 6.94 Å, respectively. Hf{sub 2}VZ (Z = Ga, In, Tl, Si and Sn) compounds exhibit half-metallicity at their respective equilibrium lattice constants. Hf{sub 2}VGe and Hf{sub 2}VPb do not exhibit half-metallicity at their equilibrium lattice constants but can present the half-metallicity when the lattice constant decreases to 6.51 and 6.71 Å, respectively. In case of the lattice thermal expansion, the half-metallicity can be kept in the range of 6.30∼ 7.27, 6.36∼ 7.80, 6.46∼ 7.35, 6.00∼ 6.70 and 6.10∼ 6.95 Å (lattice constant) for Hf{sub 2}VZ (Z = Ga, In, Tl, Si and Sn). Under the unaxial strain, the half-metallicity can still be kept for Hf{sub 2}VZ (Z = Ga, In, Tl) when the lattice distortion is up to ± 10% (c/a) and be kept for Hf{sub 2}VZ (Z = Si, Sn) when the lattice distortion is 0.88∼ 1.09, 0.91∼ 1.09 (c/a). For the Hf{sub 2}VZ compounds with half-metallicity, the total magnetic moment is 2 μ{sub B} when Z is the third main group elements and is 1 μ{sub B} when Z is the fourth main group elements. The Hf{sub 2}VZ compounds with half-metallicity obey the Slater-Pauling formula: M{sub t} = 18 − Z{sub t} rule.
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
Acceleration of electrons in the plasma wakefield of a proton bunch
High-energy particle accelerators have been crucial in providing a deeper understanding of fundamental particles and the forces that govern their interactions. To increase the energy of the particles or to reduce the size of the accelerator, new acceleration schemes need to be developed. Plasma wakefield acceleration, in which the electrons in a plasma are excited, leading to strong electric fields (so called ‘wakefields’), is one such promising acceleration technique. Experiments have shown that an intense laser pulse or electron bunch traversing a plasma can drive electric fields of tens of gigavolts per metre and above—well beyond those achieved in conventional radio-frequency accelerators (about 0.1 gigavolt per metre). However, the low stored energy of laser pulses and electron bunches means that multiple acceleration stages are needed to reach very high particle energies. The use of proton bunches is compelling because they have the potential to drive wakefields and to accelerate electrons to high energy in a single acceleration stage. Long, thin proton bunches can be used because they undergo a process called self-modulation, a particle–plasma interaction that splits the bunch longitudinally into a series of high-density microbunches, which then act resonantly to create large wakefields. The Advanced Wakefield (AWAKE) experiment at CERN uses high-intensity proton bunches—in which each proton has an energy of 400 gigaelectronvolts, resulting in a total bunch energy of 19 kilojoules—to drive a wakefield in a ten-metre-long plasma. Electron bunches are then injected into this wakefield. Here we present measurements of electrons accelerated up to two gigaelectronvolts at the AWAKE experiment, in a demonstration of proton-driven plasma wakefield acceleration. Measurements were conducted under various plasma conditions and the acceleration was found to be consistent and reliable. The potential for this scheme to produce very high-energy electron bunches in a single accelerating stage means that our results are an important step towards the development of future high-energy particle accelerators.
70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
Measurement of the spectral function for the τ − → K − K S ν τ decay
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Inclusive study of bottomonium production in association with an $\eta $ meson in $e^+e^-$ annihilations near $\varUpsilon (5S)$: Belle Collaboration
We study bottomonium production in association with an η meson in e + e - annihilations near the Υ(5S), at a centre-of-mass energy of s√=10.866 GeV. The results are based on the 121.4 fb -1 data sample collected by the Belle experiment at the asymmetric-energy KEKB collider. Only the η meson is reconstructed and the missing-mass spectrum of η candidates is investigated. We observe the e + e - →ηΥ J (1D) process and find evidence for the e + e - →ηΥ(2S) process, while no significant signals of Υ(1S), hb(1P) , nor h b (2P) are found. Cross sections for the studied processes are reported.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Local Radiation Shielding Design Methodology
The NSLS-II accelerators are housed within a radiation enclosure of normal concrete (and in some places high density concrete) that has been designed to reduce the radiation generated from an assumed operational beam loss or bulk shielding current (BCS) from each accelerator. The beam loss model used to estimate the thickness of this bulk shielding, assumed a beam energy at the expected operating energy and a current loss based on reasonable assumptions for the fraction of the expected operating current. The thickness of the shield was determined to be the amount required to reduce the radiation outside the shield to a maximum dose rate of <0.5mrem/hr. for occupied areas for these normal operational losses. These assumed beam losses and the bulk shielding thicknesses required are given in reference [1]. Abnormal operating conditions generating higher than normal beam losses must also be considered, and additional engineering controls will be required depending on the magnitude of the radiation levels generated during the abnormal condition. Additional local shielding subject to configuration control may be utilized to reduce radiation levels associated with these abnormal loss conditions. Interlocked area radiation monitors are another means to prevent continued operation with higher than an acceptable level. The NSLS-II Shielding Policy requires that an engineered system be utilized to mitigate an abnormal condition producing radiation levels greater than 100 mR/h, and that two systems are required if the projected radiation levels during a fault condition are > 2000 mR/h. It is intended that shielding limits the dose rate to < 0.5 mR/h in occupied areas for normal operational losses, and the combination of administrative and engineered controls for abnormal losses will maintain radiation exposure to trained personnel working at the NSLS-II facility to as low as reasonably achievable. It is anticipated that all individual exposures will be well within the planned administrative control level of 100mrem/year. This technical note presents the method used to identify these potential high beam loss locations, evaluate the potential radiation risk these losses create outside the enclosure shield and the design process that specifies the required local radiation shielding needed to reduce this risk below the maximum dose rate of the bulk shield design, listed above. If shielding can’t be adequately provided or if other fault initiated losses could occur, then the necessary engineering controls will be indicated that will limit the energy, current or duration of the beam transport that constitute this high beam loss risk.
36 MATERIALS SCIENCE↗
Measurement of the branching fraction of B → D ( * ) π ℓ ν at Belle using hadronic tagging in fully reconstructed events
Not Available
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Erratum: Polarization transfer observables in elastic electron-proton scattering at Q 2 =2.5 , 5.2, 6.8, and 8.5GeV 2 [Phys. Rev. C 96 , 055203 (2017)]
Subsequent to the release of our original paper, we discovered in the context of preparing our technical supplement [1] for journal publication that a typographical error had existed in the text file that the analysis program used to construct the beam polarization "database" for both the original analysis, published in Ref. [2], and our final analysis. The electron-beam polarization P e and the analyzing power A y cancel exactly in the ratio R, which is proportional to the ratio P t / P l of the transferred polarization components. On the other hand, the extraction of the relative e dependence of P l / P Born l relies on knowledge of the beam polarization. As such, data taking was interrupted roughly every two days during the GEp - 2γ experiment to perform invasive measurements of the beam polarization using the Hall C Moller polarimeter [3].
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗