Muon Trigger for Mobile Phones Borisyak, M; Usvyatsov, M; Mulhearn, M ...
Journal of physics. Conference series,
10/2017, Letnik:
898, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The CRAYFIS experiment proposes to use privately owned mobile phones as a ground detector array for Ultra High Energy Cosmic Rays. Upon interacting with Earth's atmosphere, these events produce ...extensive particle showers which can be detected by cameras on mobile phones. A typical shower contains minimally-ionizing particles such as muons. As these particles interact with CMOS image sensors, they may leave tracks of faintly-activated pixels that are sometimes hard to distinguish from random detector noise. Triggers that rely on the presence of very bright pixels within an image frame are not efficient in this case. We present a trigger algorithm based on Convolutional Neural Networks which selects images containing such tracks and are evaluated in a lazy manner: the response of each successive layer is computed only if activation of the current layer satisfies a continuation criterion. Usage of neural networks increases the sensitivity considerably comparable with image thresholding, while the lazy evaluation allows for execution of the trigger under the limited computational power of mobile phones.
Evidence for a B-s(0)pi(+/-) State Askew, A.; Aushev, V.; Avila, C. ...
Physical review letters,
07/2016, Letnik:
117, Številka:
2
Journal Article
Recenzirano
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We report evidence for a narrow structure, X(5568), in the decay sequence X(5568) -> B-s(0)pi(+/-), B-s(0) -> J/psi phi, J/psi -> mu(+)mu(-), phi -> K+K-. This is evidence for the first ...instance of a hadronic state with valence quarks of four different flavors. The mass and natural width of this state are measured to be m = 5567.8 +/- 2.9(stat)(-1.9)(+0.9) (syst) MeV/c(2) and Gamma = 21.9 +/- 6.4(stat)(-2.5)(+5.0) (syst) MeV/c(2). If the decay is X(5568) -> B-s*pi(+/-). B-s(0)gamma pi(+/-) with an unseen gamma, m(X(5568)) will be shifted up by m(B-s*) - m(B-s(0)) similar to 49 MeV/c(2). This measurement is based on 10.4 fb(-1) of p (p) over bar collision data at root s = 1.96 TeV collected by the D0 experiment at the Fermilab Tevatron collider.
We present the observation of doubly-produced $J/\psi$ mesons with the D0 detector at Fermilab in $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV. The production cross section for both singly and ...doubly-produced $J/\psi$ mesons is measured using a sample with an integrated luminosity of 8.1~fb$^{-1}$. For the first time, the double $J/\psi$ production cross section is separated into contributions due to single and double parton scatterings. Using these measurements, we determine the effective cross section \sigteff, a parameter characterizing an effective spatial area of the parton-parton interactions and related to the parton spatial density inside the nucleon.
We describe an analysis comparing the p (p) over bar elastic cross section as measured by the D0 Collaboration at a center-of-mass energy of 1.96 TeV to that in pp collisions as measured by the TOTEM ...Collaboration at 2.76, 7, 8, and 13 TeVusing a model-independent approach. The TOTEM cross sections, extrapolated to a center-of-mass energy of root s = 1.96 TeV, are compared with the D0 measurement in the region of the diffractive minimum and the second maximum of the pp cross section. The two data sets disagree at the 3.4s level and thus provide evidence for the t-channel exchange of a colorless, C-odd gluonic compound, also known as the odderon. We combine these results with a TOTEM analysis of the same C-odd exchange based on the total cross section and the ratio of the real to imaginary parts of the forward elastic strong interaction scattering amplitude in pp scattering for which the significance is between 3.4s and 4.6s. The combined significance is larger than 5 sigma and is interpreted as the first observation of the exchange of a colorless, C-odd gluonic compound.
Few paleoecological records are available to document the history of mid-elevation montane forests in the tropical Andes between 1500 and 2500 m above sea level. Archaeological studies have ...identified late-Holocene human modification of these landscapes, but it is not clear when and to what degree such alteration began. Here, we report fossil pollen, X-ray fluorescence, and charcoal data from Lake Progreso, which lies at 2013 m elevation in the eastern Peruvian Andes. The reconstruction of the effects of climate and human activity on an Andean lower montane forest is the first such high-resolution paleoecological record to span the Holocene.
The record begins in the early Holocene, with lake formation in a forested setting that lacked fire. Marked erosive events were recorded in the early and late Holocene, but not the mid-Holocene. The first evidence of human disturbance in the record was the appearance of charcoal c. 6300 cal BP. This onset of burning was followed by maize cultivation c. 4520 cal BP. The basin surrounding Lake Progreso was disturbed and burned by humans intermittently thereafter but retained a predominance of forest throughout its history. The pollen, charcoal, and XRF data suggested that the site was generally used by small groups of people or settled by a small community. The Progreso record bore overall similarities in the timing of human occupation to records from nearby Lake Pomacochas, and the lower elevation site of Lake Sauce, though both those sites showed far greater deforestation. Collectively, these data suggested that Lake Progreso supported much smaller human populations and retained more of its forest than lakes Sauce or Pomacochas. While all sites shared a history of forest burning and maize cultivation, sufficient dissimilarities existed to indicate contrasting histories of site usage.
•New data show a long history of human occupation in an Andean cloud forest.•Fires were first set 6300 years ago and maize was grown 4500 years ago.•The human footprint on the forest remained small for thousands of years.•The site was occupied during dry times and probably abandoned during wet ones.
A boundary layer field experiment in the Mexico City basin during the period 24 February–22 March 1997 is described. A total of six sites were instrumented. At four of the sites, 915-MHz radar wind ...profilers were deployed and radiosondes were released five times per day. Two of these sites also had sodars collocated with the profilers. Radiosondes were released twice per day at a fifth site to the south of the basin, and rawinsondes were flown from another location to the northeast of the city three times per day. Mixed layers grew to depths of 2500–3500 m, with a rapid period of growth beginning shortly before noon and lasting for several hours. Significant differences between the mixed-layer temperatures in the basin and outside the basin were observed. Three thermally and topographically driven flow patterns were observed that are consistent with previously hypothesized topographical and thermal forcing mechanisms. Despite these features, the circulation patterns in the basin important for the transport and diffusion of air pollutants show less day-to-day regularity than had been anticipated on the basis of Mexico City’s tropical location, high altitude and strong insolation, and topographical setting.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We present evidence for the exotic charged charmoniumlike state Zc±(3900) decaying to J/ψπ± in semi-inclusive weak decays of b-flavored hadrons. The signal is correlated with a parent J/ψπ+π− system ...in the invariant-mass range 4.2–4.7 GeV that would include the exotic structure Y(4260). The study is based on 10.4 fb−1 of pp¯ collision data collected by the D0 experiment at the Fermilab Tevatron collider.
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