The rules of a game of dice are extended to a ``hyper-die'' with \(n\in\mathbb{N}\) equally probable faces, numbered from 1 to \(n\). We derive recursive and explicit expressions for the probability ...mass function and the cumulative distribution function of the gain \(G_n\) for arbitrary values of \(n\). A numerical study suggests the conjecture that for \(n \to \infty\) the expectation of the scaled gain \(\mathbb{E}{H_n}=\mathbb{E} {G_n/\sqrt{n}\,}\) converges to \(\sqrt{\pi/\,2}\).
The conjecture is proved by deriving an analytic expression of the expected gain \(\mathbb{E} {G_n}\).
An analytic expression of the variance of the gain \(G_n\) is derived by a similar technique. Finally, it is proved that \(H_n\) converges weakly to the Rayleigh distribution with scale parameter~1.
A detector-independent toolkit for vertex reconstruction (RAVE1) is being developed, along with a standalone framework (VERTIGO2) for testing, analyzing and debugging. The core algorithms represent ...state-of-the-art for geometric vertex finding and fitting by both linear (Kalman filter) and robust estimation methods. Main design goals are ease of use, flexibility for embedding into existing software frameworks, extensibility, and openness. The implementation is based on modern object-oriented techniques, is coded in C++ with interfaces for Java and Python, and follows an open-source approach. A beta release is available.
The 'LiC Detector Toy' program Regler, M; Mitaroff, W; Valentan, M ...
Journal of physics. Conference series,
07/2008, Letnik:
119, Številka:
3
Journal Article
Recenzirano
Odprti dostop
LiC is a simple but powerful and flexible software tool, written in MatLab, for basic detector design studies (geometries, material budgets) by determining the resolution of reconstructed track ...parameters. It is based on a helix track model including multiple scattering, and consists of a simplified simulation of the detector followed by track reconstruction using the Kalman filter. After a short description of LiC's main characteristics, we demonstrate its capabilities by applying this tool in a performance study of the LDC and SiD detector concepts at the International Linear Collider (ILC).
We report the observation of a narrow charmoniumlike state produced in the exclusive decay process B+/--->K+/-pi(+)pi(-)J/psi. This state, which decays into pi(+)pi(-)J/psi, has a mass of ...3872.0+/-0.6(stat)+/-0.5(syst) MeV, a value that is very near the M(D0)+M(D(*0)) mass threshold. The results are based on an analysis of 152M B-Bmacr; events collected at the Upsilon(4S) resonance in the Belle detector at the KEKB collider. The signal has a statistical significance that is in excess of 10sigma.
Track finding in silicon trackers with a small number of layers Frühwirth, Rudolf; Glattauer, Robin; Lettenbichler, Jakob ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2013, Letnik:
732
Journal Article
Recenzirano
We present software based on novel techniques, aiming at track finding in silicon trackers with a small number of layers. The core algorithm is a cellular automaton, followed by a Kalman filter and a ...Hopfield neural network.
The first of two test cases is the forward tracking detector (FTD) of the International Large Detector (ILD) at a future linear collider, which covers the forward and backward regions between beam tube and a TPC. It consists of seven disk-shaped silicon detectors (pixels and strips) on either side. Results presented on simulated events without and with background show that our method performs better than a previous one in terms of efficiency, ghost rate and processing speed.
The second test case is the silicon vertex detector (SVD) of the Belle II experiment at the B factory at KEK, which is a new device located between a vertex pixel detector and a central drift chamber. It consists of only four cylindrical layers of silicon strip sensors. The focus of this study is on the reconstruction of tracks with very low momentum that miss the surrounding drift chamber. We present results from simulated data, including ghost hits and hits from the machine background.
Equal amounts of matter and antimatter are predicted to have been produced in the Big Bang, but our observable Universe is clearly matter-dominated. One of the prerequisites for understanding this ...elimination of antimatter is the nonconservation of charge-parity (CP) symmetry. So far, two types of CP violation have been observed in the neutral K meson (K0) and B meson (B0) systems: CP violation involving the mixing between K0 and its antiparticle (and likewise for B0 and ), and direct CP violation in the decay of each meson. The observed effects for both types of CP violation are substantially larger for the B0 meson system. However, they are still consistent with the standard model of particle physics, which has a unique source of CP violation that is known to be too small to account for the matter-dominated Universe. Here we report that the direct CP violation in charged B±→K± 0 decay is different from that in the neutral B0 counterpart. The direct CP-violating decay rate asymmetry, (that is, the difference between the number of observed B-→K- 0 event versus B+→K+ 0 events, normalized to the sum of these events) is measured to be about +7%, with an uncertainty that is reduced by a factor of 1.7 from a previous measurement. However, the asymmetry for versus B0→K+ - is at the -10% level. Although it is susceptible to strong interaction effects that need further clarification, this large deviation in direct CP violation between charged and neutral B meson decays could be an indication of new sources of CP violation-which would help to explain the dominance of matter in the Universe.
This paper presents the application of a robust estimator to the problem of finding and estimating secondary vertices. After a brief review of the standard Kalman filter and its extension to an
...M-estimator, both estimators are studied on simulated samples of charm and bottom decays. It is shown that the
M-estimator is superior to the Kalman filter. The implementation is shown to work also on real data from the LEP collider.
The lifetimes of the B(0) and B- mesons are extracted from 29.1 fb(-1) of data collected with the Belle detector at the KEK B factory. A fit to the decay length differences of neutral and charged B ...meson pairs, measured in events where one of the B mesons is fully reconstructed in several hadronic modes, yields tau(B(0)) = 1.554+/-0.030(stat)+/-0.019(syst) ps, tau(B-) = 1.695+/-0.026(stat)+/-0.015(syst) ps, and tau(B-)/tau(B(0)) = 1.091+/-0.023(stat)+/-0.014(syst).
We report the first measurement of the branching fraction for the inclusive decay B-->X(s)l(+)l(-), where l is either an electron or a muon, and X(s) is a hadronic recoil system that contains an s ...quark. We analyzed a data sample of 65.4 x 10(6) B meson pairs collected with the Belle detector at the KEKB e(+)e(-) asymmetric-energy collider. We find B(B-->X(s)l(+)l(-))=6.1 +/-1.4(stat) +1.4-1.1(syst) x 10(-6) for dilepton masses greater than 0.2 GeV/c(2).
We report the first measurements of the doubly charmed baryonic B decays B --> Lambda c+ Lambda c- K. The B+ --> Lambda c+ Lambda c- K+ decay is observed with a branching fraction of ...(6.5(-0.9)(+1.0)+/-1.1+/-3.4)x10(-4) and a statistical significance of 15.4sigma. The B0 --> Lambda c+ Lambda c- K0 decay is observed with a branching fraction of (7.9(-2.3)(+2.9)+/-1.2+/-4.1)x10(-4) and a statistical significance of 6.6sigma. The branching fraction errors are statistical, systematic, and the error resulting from the uncertainty of the Lambda c+ --> pK- pi+ decay branching fraction. The analysis is based on 357 fb(-1) of data accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.
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