We present the observation of doubly produced $J / \psi$ mesons as an example of processes containing a substantial fraction of double parton scattering. Measurements of the production cross sections ...for singly and doubly-produced $J/\psi$ mesons were done with the D0 detector at Fermilab in $p\bar{p}$ collisions at $\sqrt{s}$ = 1.96 TeV with an integrated luminosity of 8.1 fb$^{-1}$. For the first time, the double $J / \psi$ production cross section is separated into two parts: contributions from both single and double parton scattering. Lastly, this separation allowed us to determine the effective cross section σeff, a parameter related to the parton spatial density inside the hadron.
A
bstract
The production of
D
0
,
D
*
+
,
D
+
,
and
charm hadrons and their antiparticles in
ep
scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 ...pb
−1
. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged
D
-meson production rates, the fraction of charged
D
mesons produced in a vector state, and the stangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum
p
T
>
3
.
8 GeV and pseudorapidity |
η
|
<
1
.
6. The charm fragmentation fractions are compared to previous results from HERA and from
e
+
e
−
experiments. The data support the hypothesis that fragmentation is independent of the production process.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
We measure the top quark mass in dilepton final states of tt¯ events in pp¯ collisions at s=1.96 TeV, using data corresponding to an integrated luminosity of 9.7 fb−1 at the Fermilab Tevatron ...Collider. The analysis features a comprehensive optimization of the neutrino weighting method to minimize the statistical uncertainties. We also improve the calibration of jet energies using the calibration determined in tt¯→lepton+jets events, which reduces the otherwise limiting systematic uncertainty from the jet energy scale. The measured top quark mass is mt=173.32±1.36(stat)±0.85(syst) GeV.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A search for single-top production, ep→etX, has been performed with the ZEUS detector at HERA using data corresponding to an integrated luminosity of 0.37 fb−1. No evidence for top production was ...found, consistent with the expectation from the Standard Model. Limits were computed for single-top production via flavour changing neutral current transitions involving a neutral electroweak vector boson, γ or Z. The result was combined with a previous ZEUS result yielding a total luminosity of 0.50 fb−1. A 95% credibility level upper limit of 0.13 pb was obtained for the cross section at the centre-of-mass energy of s=315 GeV.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Abstract We report results from a study of B ± → DK ± decays followed by D decaying to the CP-even final state K + K − and CP-odd final state K S 0 π 0 $$ {K}_S^0{\pi}^0 $$ , where D is an admixture ...of D 0 and D ¯ 0 $$ {\overline{D}}^0 $$ states. These decays are sensitive to the Cabibbo-Kobayashi-Maskawa unitarity-triangle angle ϕ 3. The results are based on a combined analysis of the final data set of 772 × 106 B B ¯ $$ B\overline{B} $$ pairs collected by the Belle experiment and a data set of 198 × 106 B B ¯ $$ B\overline{B} $$ pairs collected by the Belle II experiment, both in electron-positron collisions at the Υ(4S) resonance. We measure the CP asymmetries to be A $$ \mathcal{A} $$ CP+ = (+12.5 ± 5.8 ± 1.4)% and A $$ \mathcal{A} $$ CP− = (−16.7 ± 5.7 ± 0.6)%, and the ratios of branching fractions to be R $$ \mathcal{R} $$ CP+ = 1.164 ± 0.081 ± 0.036 and R $$ \mathcal{R} $$ CP− = 1.151 ± 0.074 ± 0.019. The first contribution to the uncertainties is statistical, and the second is systematic. The asymmetries A $$ \mathcal{A} $$ CP+ and A $$ \mathcal{A} $$ CP− have similar magnitudes and opposite signs; their difference corresponds to 3.5 standard deviations. From these values we calculate 68.3% confidence intervals of (8.5 ° < ϕ 3 < 16.5 ° ) or (84.5 ° < ϕ 3 < 95.5 ° ) or (163.3 ° < ϕ 3 < 171.5 ° ) and 0.321 < r B < 0.465.
Single- and double-differential inclusive dijet cross sections in neutral current deep inelastic
ep
scattering have been measured with the ZEUS detector using an integrated luminosity of 374 pb
−1
. ...The measurement was performed at large values of the photon virtuality,
Q
2
, between 125 and 20 000 GeV
2
. The jets were reconstructed with the
k
T
cluster algorithm in the Breit reference frame and selected by requiring their transverse energies in the Breit frame,
, to be larger than 8 GeV. In addition, the invariant mass of the dijet system,
, was required to be greater than 20 GeV. The cross sections are described by the predictions of next-to-leading-order QCD.
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DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, SIK, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Abstract We measure CP asymmetries and branching-fraction ratios for B ± → DK ± and Dπ ± decays with D → K S 0 $$ {K}_{\textrm{S}}^0 $$ K ± π ∓, where D is a superposition of D 0 and D ¯ $$ ...\overline{D} $$ 0. We use the full data set of the Belle experiment, containing 772 × 106 B B ¯ $$ B\overline{B} $$ pairs, and data from the Belle II experiment, containing 387 × 106 B B ¯ $$ B\overline{B} $$ pairs, both collected in electron-positron collisions at the Υ(4S) resonance. Our results provide model-independent information on the unitarity triangle angle ϕ 3.
Conducting a study on this topic becomes relevant due to the great importance of the safety of critical infrastructure facilities and the presence of operational defects in equipment elements and ...pipelines, which poses serious threats, including the possibility of equipment destruction and negative environmental impact. The purpose of this work is to study the possibility of using the diffraction-time technique of ultrasonic non-destructive testing together with a deep convolutional neural network to accurately determine the numerical value of the height of an operational crack. The methods used include the analytical method, classification method, functional method, statistical method, synthesis method, and others. The study found that an automated approach to measuring crack height, based on diffraction signals and the use of neural networks, significantly improved the quality and accuracy of non-destructive testing. Ultrasonic testing is one of the most common inspection methods for detecting service cracks and is considered to be the most effective. It allows for reliable detection of defects and determination of their size without destroying the product. The results of the study emphasize the high potential and efficiency of the method in analysing the data obtained and provide confirmation of its applicability for determining the condition of objects during ultrasonic inspection. The paper emphasizes that these technologies are particularly important and effective. It is noted that their widespread use in various industries, such as medicine, aviation, and machine learning, demonstrates their power in solving complex problems. The practical significance of the work lies in the development of advanced approaches that provide new insights and methods to improve the efficiency of analysing the results, which can be applied in industry to improve the quality of control and reliability of technical facilities
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