A search for the Bs0 → D∗±D decay is performed using proton-proton collision data at centre-of-mass energies of 7, 8 and 13 TeV collected by the LHCb experiment, corresponding to an integrated luminosity of 9 fb...
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In this paper, we present a method of estimating the vanishing point from the railway environment images. Vanishing point plays a very important role in the machine vision based railway-environment surveillance method...
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In this paper, we present a method of estimating the vanishing point from the railway environment images. Vanishing point plays a very important role in the machine vision based railway-environment surveillance methods, e.g. estimating the pose of the camera, video segmentation and panorama. In the application of railway-environment surveillance, we most care about the vanishing point corresponding to the lines parallel to the rails. Based on the prior, we design a fast and effective method-Selected Line Segment Detector(SLSD) to detect the line segments corresponding to the scene-lines parallel to the rails, and then use a cross-iteration method to find the vanishing point in the railway environment images. We give both theoretical analysis and algorithm implementation. Our experimental results show the validation of the proposed method.
New results on the galactic cosmic ray (GCR) short-term intensity variation associated with Forbush decrease and co-rotating interaction regions (CIRs) measured by the PAMELA instrument between November 2006 and March...
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A general wireless sensor network (WSN) is a system composed of a large number of sensor nodes. In the WSN system, all sensor nodes are responsible for sensing the interested events and transmitting the related inform...
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An angular analysis of B0→J/ψK+π− decays is performed, using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected with the LHCb detector. The m(K+π−) spectrum is divided into...
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An angular analysis of B0→J/ψK+π− decays is performed, using proton-proton collision data corresponding to an integrated luminosity of 3 fb−1 collected with the LHCb detector. The m(K+π−) spectrum is divided into fine bins. In each m(K+π−) bin, the hypothesis that the three-dimensional angular distribution can be described by structures induced only by K* resonances is examined, making minimal assumptions about the K+π− system. The data reject the K*-only hypothesis with a large significance, implying the observation of exotic contributions in a model-independent fashion. Inspection of the m(J/ψπ−) vs m(K+π−) plane suggests structures near m(J/ψπ−)=4200 and 4600 MeV.
A search for charge-parity (CP) violation in Cabibbo-suppressed Ds+→KS0π+, D+→KS0K+, and D+→ϕπ+ decays is reported using proton-proton collision data, corresponding to an integrated luminosity of 3.8 fb−1, colle...
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A search for charge-parity (CP) violation in Cabibbo-suppressed Ds+→KS0π+, D+→KS0K+, and D+→ϕπ+ decays is reported using proton-proton collision data, corresponding to an integrated luminosity of 3.8 fb−1, collected at a center-of-mass energy of 13 TeV with the LHCb detector. High-yield samples of kinematically and topologically similar Cabibbo-favored D(s)+ decays are analyzed to subtract nuisance asymmetries due to production and detection effects, including those induced by CP violation in the neutral kaon system. The results are ACP(Ds+→KS0π+)=(1.3±1.9±0.5)×10−3,ACP(D+→KS0K+)=(−0.09±0.65±0.48)×10−3,ACP(D+→ϕπ+)=(0.05±0.42±0.29)×10−3,where the first uncertainties are statistical and the second systematic. They are the most precise measurements of these quantities to date, and are consistent with CP symmetry. A combination with previous LHCb measurements, based on data collected at 7 and 8 TeV, is also reported.
Results are reported from a search for the rare decays Bs0→τ±μ∓ and B0→τ±μ∓, where the τ lepton is reconstructed in the channel τ−→π−π+π−ντ. These processes are effectively forbidden in the sta...
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Results are reported from a search for the rare decays Bs0→τ±μ∓ and B0→τ±μ∓, where the τ lepton is reconstructed in the channel τ−→π−π+π−ντ. These processes are effectively forbidden in the standard model, but they can potentially occur at detectable rates in models of new physics that can induce lepton-flavor-violating decays. The search is based on a data sample corresponding to 3 fb−1 of proton-proton collisions recorded by the LHCb experiment in 2011 and 2012. The event yields observed in the signal regions for both processes are consistent with the expected standard model backgrounds. Because of the limited mass resolution arising from the undetected τ neutrino, the Bs0 and B0 signal regions are highly overlapping. Assuming no contribution from B0→τ±μ∓, the upper limit B(Bs0→τ±μ∓)<4.2×10−5 is obtained at 95% confidence level. If no contribution from Bs0→τ±μ∓ is assumed, a limit of B(B0→τ±μ∓)<1.4×10−5 is obtained at 95% confidence level. These results represent the first limit on B(Bs0→τ±μ∓) and the most stringent limit on B(B0→τ±μ∓).
The production of charged hadrons within jets recoiling against a Z boson is measured in proton-proton collision data at s=8 TeV recorded by the LHCb experiment. The charged-hadron structure of the jet is studied lon...
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The production of charged hadrons within jets recoiling against a Z boson is measured in proton-proton collision data at s=8 TeV recorded by the LHCb experiment. The charged-hadron structure of the jet is studied longitudinally and transverse to the jet axis for jets with transverse momentum pT>20 GeV and in the pseudorapidity range 2.5<η<4. These are the first measurements of jet hadronization at these forward rapidities and also the first where the jet is produced in association with a Z boson. In contrast to previous hadronization measurements at the Large Hadron Collider, which are dominated by gluon jets, these measurements probe predominantly light-quark jets which are found to be more longitudinally and transversely collimated with respect to the jet axis when compared to the previous gluon dominated measurements. Therefore, these results provide valuable information on differences between quarks and gluons regarding nonperturbative hadronization dynamics.
The first observation of the decays B(s)0→J/ψpp¯ is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb−1, collected with the LHCb detector. These decays are suppre...
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The first observation of the decays B(s)0→J/ψpp¯ is reported, using proton-proton collision data corresponding to an integrated luminosity of 5.2 fb−1, collected with the LHCb detector. These decays are suppressed due to limited available phase space, as well as due to Okubo-Zweig-Iizuka or Cabibbo suppression. The measured branching fractions are B(B0→J/ψpp¯)=[4.51±0.40(stat)±0.44(syst)]×10−7, B(Bs0→J/ψpp¯)=[3.58±0.19(stat)±0.39(syst)]×10−6. For the Bs0 meson, the result is much higher than the expected value of O(10−9). The small available phase space in these decays also allows for the most precise single measurement of both the B0 mass as 5279.74±0.30(stat)±0.10(syst) MeV and the Bs0 mass as 5366.85±0.19(stat)±0.13(syst) MeV.
A measurement of the ratio of branching fractions of the decays B+→K+μ+μ− and B+→K+e+e− is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0 fb−1 recorded with the LHC...
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A measurement of the ratio of branching fractions of the decays B+→K+μ+μ− and B+→K+e+e− is presented. The proton-proton collision data used correspond to an integrated luminosity of 5.0 fb−1 recorded with the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV. For the dilepton mass-squared range 1.1ainty is statistical and the second systematic. This is the most precise measurement of RK to date and is compatible with the standard model at the level of 2.5 standard deviations.
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