Abstract
In 2018, a test run with muons in the North Area at CERN was
performed, running parasitically downstream of the COMPASS
spectrometer. The aim of the test was to investigate the elastic
...interactions of muons on atomic electrons, in an experimental
configuration similar to the one proposed by the project MUonE,
which plans to perform a very precise measurement of the
differential cross-section of the elastic interactions.
COMPASS was taking data with a 190 GeV π beam, stopped in a
tungsten beam dump: the muons from these π decays passed through
a setup including a graphite target followed by 10 planes of Si
tracker and a BGO crystal electromagnetic calorimeter placed at the
end of the tracker. The elastic scattering events were selected and
analysed, and compared to expectations from MonteCarlo
simulation. The agreement found was satisfactory and demonstrated
that measuring the angles of the outgoing particles, a clean sample
of elastic interaction could be identified.
A study of the sensitivity of the CLIC ILD detector model for massive long-lived particles produced in the decay of the Higgs boson is presented, using a data sample of \(e^+e^-\) collisions at ...centre-of-mass energy of 350 GeV and 3 TeV, corresponding to an integrated luminosity of 1 ab-1 and 3 ab-1, respectively. The sensitivity range covers long-lived particle lifetimes from 1 to 300 ps, masses between 25 and 50 GeV, and a parent Higgs mass of 126 GeV. Sensitivities to the production cross-section as a function of the long-lived particle mass and lifetime are determined.
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Using proton-proton collision data at centre-of-mass energies of s=7,8 and 13TeV recorded by the LHCb experiment at the Large Hadron Collider, corresponding to an integrated ...luminosity of 9fb-1, the invariant mass spectrum of J/ψ pairs is studied. A narrow structure around 6.9GeV/c2 matching the lineshape of a resonance and a broad structure just above twice the J/ψ mass are observed. The deviation of the data from nonresonant J/ψ-pair production is above five standard deviations in the mass region between 6.2 and 7.4GeV/c2, covering predicted masses of states composed of four charm quarks. The mass and natural width of the narrow X(6900) structure are measured assuming a Breit-Wigner lineshape.
In cardiac resynchronisation therapy (CRT), the coronary venous system is used for left ventricular pacing electrode placement. Despite the well- -known anatomy of the coronary sinus and its ...tributaries, heart failure patients' remodelled and enlarged left ventricles may impede the successful lead placement because of acquired anatomical obstacles.
Fifty-five patients qualified for CRT treatment were divided into ischaemic and non-ischaemic cardiomyopathy. Forty-four control groups without heart failure underwent dual-source computed tomography (CT). Rendered reconstructions of cardiac coronary systems were compared.
The presence of main tributaries was comparable in all groups. The left marginal vein, small cardiac vein, and oblique vein of the left atrium were present in 63%, 60%, and 51% of the hearts in all the groups. CRT referred CTs had significantly longer distances between posterior and lateral cardiac veins over the left ventricle (p < 0.05), wider angles of tributaries (p = 0.03), and smaller lumen of coronary sinus (p = 0.03). In the non-ischaemic group, the posterior interventricular and great cardiac veins are more extensive than in the control group. Age-related analysis of vessel size shows a moderate correlation between age and diminishing mean vessel size in all the groups studied.
The general structure of the coronary heart system is consistent in patients with and without heart failure. The variance of the general structure, or the presence of adequate veins, is an individual variation. The use of CT and analysis of the coronary veins allow better planning of the CRT-D implantation procedure and may reduce the risk of ineffective left ventricular electrode implantation.
The autonomic nervous system can be visualized with a 3D map created in the CARTO® 3 system. This advanced imaging technology utilizes electromagnetic technology to create real-time three-dimensional ...(3D) maps of a patient's cardiac structures. Unique electrocardiograms with established length and fractionations reflect the position of neuronal ganglionated plexi. Radiofrequency ablation of such ganglionated plexi modifies chronotropic and dromotropic effects, potentially reducing recurrences of atrial fibrillation.
The present study provides quantitative and qualitative information about the presence of ganglionated plexi in specific heart regions among patients with paroxysmal atrial fibrillation.
Thirty-five patients referred for primary atrial fibrillation ablation were retrospectively inspected for ganglionated plexi presence in high-density mapping. Right anterior and left superior ganglionated plexus were consistently observed in all hearts. Other ganglionated plexi were tracked from 85.7 – to 42.8%. Less often, fragmented potentials were observed in the coronary sinus. The highest amount of low amplitude potentials was recorded in the left inferior ganglionated plexus.
Using a high-density mapping, ganglionated plexi identification is quick and feasible in reconsidering ablation strategy for selected patients who develop atrial fibrillation.
•The cardiac autonomic nervous system has an impact on acute atrial electrical remodeling inducing atrial fibrillation.•Fractionated atrial potentials reflect the position of neuronal ganglionated plexi.•The study aimed to localize the fractionated potentials in the left atrium using high-density mapping.
The branching fraction of the rare decay Λ b0 → Λ ( 1520 ) μ+μ- is measured for the first time, in the squared dimuon mass intervals q2 , excluding the J/ψ and ψ ( 2S ) regions. The data sample ...analyzed was collected by the LHCb experiment at center-of-mass energies of 7, 8, and 13 TeV, corresponding to a total integrated luminosity of 9 fb-1 . The result in the highest q2 interval, q2>15.0 GeV2/c4 , where theoretical predictions have the smallest model dependence, agrees with the predictions.
The production rate of $Λ^{0}_{b}$ baryons relative to $B$0 mesons in $pp$ collisions at a center-of-mass energy $\sqrt{s}$ = $13$ $TeV$ is measured by the LHCb experiment. The ratio of $Λ^{0}_{b}$ ...to $B$0 production cross sections shows a significant dependence on both the transverse momentum and the measured charged-particle multiplicity. At low multiplicity, the ratio measured at LHCb is consistent with the value measured in e+e- collisions, and increases by a factor of ~ 2 with increasing multiplicity. At relatively low transverse momentum, the ratio of $Λ^{0}_{b}$ to $B$0 cross sections is higher than what is measured in e+e- collisions, but converges with the e+e- ratio as the momentum increases. These results imply that the evolution of heavy $b$ quarks into final-state hadrons is influenced by the density of the hadronic environment produced in the collision. Comparisons with several models and implications for the mechanisms enforcing quark confinement are discussed.
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