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 article describes a new method of reliability assessment of human performance that derives from systemic-structural activity theory (SSAT). This method is demonstrated by applying it to the ...study of a human-computer interaction task. The task that has been selected is typical for users who interact with computers. One of the basic methods of SSAT called morphological analysis of activity has been used to examine and describe the computer-based task that was the object of study. Cognitive and behavioral actions and members of human algorithm have been utilized as main units of analysis. Suggested method provides analytical description of activity during task performance. It allows to determine the reliability of task performance and to find more reliable performance methods.
The electronic width of the
J
/
ψ
meson and its product by the branching fractions of
J
/
ψ
meson decay to hadrons and electrons measured with the KEDR detector at the VEPP-4M
e
+
e
−
collider have ...been reported in ref. 1.
Measurement of Γee(J/ψ) with KEDR detector Anashin, V. V; Aulchenko, V. M; Baldin, E. M ...
The journal of high energy physics,
05/2018, Letnik:
2018, Številka:
5
Journal Article
Recenzirano
Odprti dostop
A
bstract
The product of the electronic width of the
J/ψ
meson and the branching fractions of its decay to hadrons and electrons has been measured using the KEDR detector at the VEPP-4M
e
+
e
−
...collider. The obtained values are
Γ
e
e
J
/
ψ
=
5.550
±
0.056
±
0.089
keV
,
Γ
e
e
J
/
ψ
·
ℬ
hadrons
J
/
ψ
=
4.884
±
0.048
±
0.078
keV
,
Γ
e
e
J
/
ψ
·
ℬ
e
e
J
/
ψ
=
0.3331
±
0.0066
±
0.0040
keV
.
The uncertainties shown are statistical and systematic, respectively. Using the result presented and the world-average value of the electronic branching fraction, one obtains the total width of the
J/ψ
meson:
Γ
=
92.94
±
1.83
keV
.
These results are consistent with the previous experiments.
The KEDR detector Anashin, V. V.; Aulchenko, V. M.; Baldin, E. M. ...
Physics of particles and nuclei,
07/2013, Letnik:
44, Številka:
4
Journal Article
Recenzirano
The KEDR detector is a universal magnetic detector designed for studying the
c
- and
b
-quarks and two-photon physics, and is employed at the VEPP-4M
e
+
e
−
collider. A specific feature of the ...experiment is the measurement of absolute beam energy using two methods: the resonant depolarization and the faster but less precise Compton backscattering of laser photons. This allowed a large series of measurements to be performed, in which the accuracy of determination of such fundamental parameters of particles as mass and total and leptonic widths was improved.
The mathematical model for determining the errors during manufacturing of satellite gears of planetary gearboxes is modified. The algorithm for revealing and rejecting incorrect source data in an ...automated and manual mode has been developed and implemented in software. The directions of further studies are outlined.
Study of the radiation hardness of the pure CsI crystals Bedny, I.V.; Bondar, A.E.; Cherepkov, V.V. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2009, 2009-1-00, Letnik:
598, Številka:
1
Journal Article
Recenzirano
This study was initiated by the Belle detector upgrade plan including the replacement of the CsI(Tl) crystals in the endcaps by the pure CsI. Within this work five samples of pure CsI crystals were ...irradiated by the beam of
0.6
MeV
γ
-quanta. The absorbed dose accumulated in several runs reached 55
krad for two samples and 13
krad for three others. Four of these samples were found to satisfy the super B-factory conditions. The light output reduction for them does not exceed 15% at 13
krad of absorbed dose. One sample had poor radiation resistance.
An algorithm and program to calculate the pressure distribution on the surface of a cylindrical oscillating shell immersed into a fluid with a given form of its oscillations have been developed. ...Pressure calculation examples are presented.
In the paper, practical control methods for complex errors of satellite units of planetary reducers used in manufacturing plants are considered. Proposals to improve the evaluation accuracy of these ...errors are formulated. A mathematical model for implementing these proposals is presented.
We search for lepton-flavor-violating τ decays into a lepton (electron or muon) and an f0(980) meson using 671 fb−1 of data collected with the Belle detector at the KEKB asymmetric-energy e+e− ...collider. No events are observed and we set the following 90% C.L. upper limits on the branching fraction products: B(τ−→e−f0(980))×B(f0(980)→π+π−)<3.2×10−8 and B(τ−→μ−f0(980))×B(f0(980)→π+π−)<3.4×10−8. This is the first search performed for these modes.
PDF
