Progress on development of the new FDIRC PID detector Va'vra, J.; Arnaud, N.; Barnyakov, A.Yu ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
08/2013, Letnik:
718
Journal Article
Recenzirano
Odprti dostop
We present a progress status of a new concept of PID detector called FDIRC, intended to be used at the SuperB experiment, which requires π/K separation up to a few GeV/c. The new photon camera is ...made of the solid fused-silica optics with a volume 25× smaller and speed increased by a factor of 10 compared to the BaBar DIRC, and therefore will be much less sensitive to electromagnetic and neutron background.
We analyzed the space weather events of 6–10 September 2017 using the multi‐instrument approach. We focused on the four X‐class flares which emanated from the Active Region AR 12673 and the Ground ...Induced Currents hazard associated with the geomagnetic storm of 7–8 September 2017. The flare effect on the equatorial electrojet (EEJ) recorded on board the SWARM satellite and on the horizontal component of the geomagnetic field (H) records of ground‐based magnetometers was further examined. During the X2.2/X1.3 flares of 6/7 September, the maximum percentage Global Navigation Satellite System (GNSS) vertical Total Electron Content (VTEC) increase was 6.9%/5.0% in Dakar/Porto Velho. During the X9.3/X8.2 flare of 6/10 September it was 7.9%/18.8% in Ascension Island/Kourou. The strongest Solar Flare Effect occurred in Mbour and Kourou during the respective flare. However, the highest EEJ increase was observed during the X2.2 and X9.3 flares. Interestingly, the X.9.3 flare resulted in a stronger ionospheric response than the X8.2 flare. Furthermore, global TEC map showed a higher response in the African and South American longitude during the respective event. The total radio fade‐out lasted from 30 to 90 min at the Hermanus and Sao Luis ionosondes during the flares, while the risk level to critical ground infrastructures based on the geomagnetically induced currents hazard was very low risk. Our results highlight the potential GPS positioning errors induced by sudden increase in TEC and the loss of high‐frequency communication and GNSS navigation signals associated with these solar events.
Plain Language Summary
Space weather refers to changes on the Sun, solar wind and magnetosphere that can affect the performance of technological systems in space and on ground. Solar flares and coronal mass ejections are typical examples of space weather. Several Coronal Mass Ejections (CMEs) and solar flares occurred in the month of September 2017. We have focused on the X‐class solar flares of 4–10 September and the Ground Induced Currents (GICs) related with the geomagnetic storm of 7/8 September. The X9.3/X8.2 flare had enhanced the ionospheric total electron content by about 7.9%/18.8% in Ascension Island/Kourou on 6/10 September. The highest sudden increase in the horizontal component of the geomagnetic field was observed in Mbour and Kourou during the respective flare. The largest changes in ionospheric current in the E region occurred during the X2.2 and X9.3 flares on 6 September. The flares also caused total radio fade‐out for over 30–90 min at the Hermanus and Sao Luis ionosondes. The GICs however, represented a low risk to critical ground infrastructures such as power grids, as well as oil and gas pipelines.
Key Points
The X9.3/X8.7 flare induced peak vertical Total Electron Content increase of 7.9%/18.8% in Ascension Island/Kourou with rise time of 2/9 min
The total radio fade‐out lasted from 30 to 90 min at the Hermanus and Sao Luis ionosondes during the flares
The risk level to critical ground infrastructures based on the Ground Induced Current hazard was very low at the low‐latitude
Based on the full BABAR data sample, we report improved measurements of the ratios R(D(*))=B(B̄→D(*)τ⁻ν¯τ)/B(B̄→D(*)ll¯ν¯l), where l is either e or μ. These ratios are sensitive to new physics ...contributions in the form of a charged Higgs boson. We measure R(D)=0.440±0.058±0.042 and R(D*)=0.332±0.024±0.018, which exceed the standard model expectations by 2.0σ and 2.7σ, respectively. Taken together, our results disagree with these expectations at the 3.4σ level. This excess cannot be explained by a charged Higgs boson in the type II two-Higgs-doublet model.
Study of H-8500 MaPMT for the FDIRC detector at SuperB Gargano, F.; Arnaud, N.; Barnyakov, A.Yu ...
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment,
08/2013, Letnik:
718
Journal Article, Conference Proceeding
Recenzirano
An overview of ongoing studies on the Hamamatsu H-8500 Multi-Anode Photomultiplier (MaPMT) is presented. This device will be used for the FDIRC Particle Identification Detector (PID) of the SuperB ...experiment. The H-8500 MaPMT has been chosen for its excellent single photon timing capabilities and its highly pixilated design. Results on timing studies, gain uniformity, single photoelectron detection efficiency uniformity and cross-talk are presented.
In this paper, through a case study, an attempt has been made to bring out the relationship between post noon E-region electric field and post sunset F-region vertical plasma drift on quiet time ...Counter Electrojet (CEJ) days. Study carried out using the data from a multi frequency HF Doppler Radar and Digital Ionosonde located over Trivandrum (8.5° N; 77° E; 0.5° N dip lat.) a geomagnetic dip equatorial station in India during quite time CEJ days of the years 2004 and 2006, revealed some interesting aspects of the E region electrodynamics and post sunset F region electrodynamics. It has been observed that, in contrast to the normal electrojet (EEJ) days, the Pre-Reversal Enhancement (PRE) is either weakened or inhibited on CEJ days and the field reversal takes place much earlier than that on a normal day. It is suggested that even after the effects of the field reversal ceases to show up in the ground magnetic data, the reversed field may persist and shows up as a decrease in the PRE experienced by the F-region. In other words, the study indicates that the EEJ associated electrodynamics have a significant role in controlling the PRE.
The Heavy Photon Search experiment took its first data in a 2015 engineering run using a 1.056 GeV, 50 nA electron beam provided by CEBAF at the Thomas Jefferson National Accelerator Facility, ...searching for a prompt, electroproduced dark photon with a mass between 19 and 81 MeV/c2. A search for a resonance in the e+e− invariant mass distribution, using 1.7 days (1170 nb−1) of data, showed no evidence of dark photon decays above the large QED background, confirming earlier searches and demonstrating the full functionality of the experiment. Upper limits on the square of the coupling of the dark photon to the standard model photon are set at the level of 6×10−6. Future runs with higher luminosity will explore new territory.
The process e+e−→π+π−2π0γ is investigated by means of the initial-state radiation technique, where a photon is emitted from the incoming electron or positron. Using 454.3 fb−1 of data collected ...around a center-of-mass energy of s=10.58 GeV by the BABAR experiment at SLAC, approximately 150000 signal events are obtained. The corresponding nonradiative cross section is measured with a relative uncertainty of 3.6% in the energy region around 1.5 GeV, surpassing all existing measurements in precision. Using this new result, the channel’s contribution to the leading order hadronic vacuum polarization contribution to the anomalous magnetic moment of the muon is calculated as (gμπ+π−2π0−2)/2=(17.9±0.1stat±0.6syst)×10−10 in the energy range 0.85 GeV<ECM<1.8 GeV. In the same energy range, the impact on the running of the fine-structure constant at the Z0-pole is determined as Δαπ+π−2π0(MZ2)=(4.44±0.02stat±0.14syst)×10−4. Furthermore, intermediate resonances are studied and especially the cross section of the process e+e−→ωπ0→π+π−2π0 is measured.
We present a new way of studying the classical and still unsolved problem of the reconstruction of a domino tiling from its row and column projections. After giving a simple greedy strategy for ...solving the problem from one projection, we introduce the concept of degree of a domino tiling. We generalize an algorithm for the reconstruction of domino tilings of degree two from two projections, to domino tilings of degree three and four.
A precise measurement of the cross section of the process $e^+e^-\to\pi^+\pi^-(\gamma)$ from threshold to an energy of 3GeV is obtained with the initial-state radiation (ISR) method using $232\invfb$ ...of data collected with the BaBar detector at $e^+e^-$ center-of-mass energies near 10.6GeV. The ISR luminosity is determined from a study of the leptonic process $e^+e^-\to\mu^+\mu^-(\gamma)\gamma_{\rm ISR}$, which is found to agree with the next-to-leading-order QED prediction to within 1.1%. The cross section for the process $e^+e^-\to\pi^+\pi^-(\gamma)$ is obtained with a systematic uncertainty of 0.5% in the dominant $\rho$ resonance region. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the measured $\pi\pi$ cross section from threshold to 1.8GeV is $(514.1 \pm 2.2({\rm stat}) \pm 3.1({\rm syst}))\times 10^{-10}$.
The aim of the study was to measure circulating BDNF levels, a neurotrophin recently identified in the ovary, in parallel with estradiol, to verify if assessing this factor could add any predictive ...value to the outcome of in vitro fertilization.
Blood sampling for BDNF and estradiol was performed in 23 subjects undergoing IVF on day 1 (D1), day 8 (D8), day of HCG administration (DHCG) and day of oocyte retrieval.(DOR).
There was a positive correlation between BDNF and estradiol throughout the stimulation cycle in all subjects. In both pregnant and nonpregnant patients, the values of BDNF grew significantly only between D8 and DHCG and remained constant until DOR. Between-group comparisons showed no statistically significant differences in both BDNF and estradiol values throughout the IVF cycle.
Although BDNF plasma concentrations are not seemingly predictive of IVF outcome, this neurotrophin is highly correlated to estradiol levels and seems to be an important factor especially in the periovulatory period.
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