The Super Charm-Tau Factory project proposed at Budker Institute of Nuclear Physics, Siberian Branch, Russian Academy of Sciences, in Novosibirsk is discussed. An electron–positron collider with the ...luminosity of
cm
s
and energies of 2 to 6 GeV in the beam center-of-mass frame and with a state-of-the-art particle detector arranged at the point of
interaction will permit studying, at a new precision level, the physics of charmonium, exotic charmonium-like states, charmed mesons and baryons, and the tau lepton, as well as the production of light hadrons in
-annihilation processes and in two-photon processes. A longitudinal polarization of the electron beam at the interaction point will provide a number of competitive advantages to the Super Charm-Tau Factory in relation to Super B factories such as Belle II and LHCb.
A
bstract
We propose a new method to probe the magnetic and electric dipole moments of the
τ
lepton using precise measurements of the differential rates of radiative leptonic
τ
decays at ...high-luminosity
B
factories. Possible deviations of these moments from the Standard Model values are analyzed in an effective Lagrangian approach, thus providing model-independent results. Analytic expressions for the relevant non-standard contributions to the differential decay rates are presented. Earlier proposals to probe the
τ
dipole moments are examined. A detailed feasibility study of our method is performed in the conditions of the Belle and Belle II experiments at the KEKB and Super-KEKB colliders, respectively. This study shows that our approach, applied to the planned full set of Belle II data for radiative leptonic
τ
decays, has the potential to improve the present experimental bound on the
τ
anomalous magnetic moment. On the contrary, its foreseen sensitivity is not expected to lower the current experimental limit on the
τ
electric dipole moment.
Michel parameters are kinematic values defined as bilinear combinations of the coupling terms in the general matrix element of the Fermi interaction where all possible Lorentz-invariant scalar, ...vector and tensor terms are included. The leptonic τ decays provide an excellent laboratory in which to measure the Michel parameters. Any deviation of these parameters from the Standard Model expectation would indicate New Physics. Two Michel parameters, η¯ and ξκ, can only be measured in the radiative leptonic decay. These parameters have previously been measured in the radiative decay of the muon but as yet have not been measured in τ decays. We report the results of a feasibility study of the measurement of η¯ and ξκ in radiative leptonic τ decays at Belle and Belle II.
Nowadays, vertebral stenosis is the most common indication for surgical treatment in patients over 65 years old in spine surgery. According to the literature, there are conflicting data on the ...incidence and indications for revision surgery after previous spinal decompression and fusion for lumbar spinal stenosis.
To evaluate the incidence and indications for revision surgery after previous spinal decompression and fusion for lumbar spinal stenosis.
A retrospective single-center study enrolled 1233 patients with lumbar spine stenosis who underwent spinal decompression and fusion surgery between 2014 and 2018. The number and causes of readmission were evaluated.
There were 164 readmissions. Revision surgery at the same level was performed in 63 patients (38.4%), at the higher level - 72 (43.9%), at the lower level - in 29 (17.7%) patients. The most common indication for readmission was spondyloarthrosis with facet joint syndrome (94 (57.3%) patients). The second common complication was pseudoarthrosis (26 (15.9%) patients). These ones comprised 2.1% of all patients with lumbar spine stenosis.
The most common indication for readmission was adjacent segment degeneration. The most severe complications requiring complex and even multiple stage revision surgery were pseudoarthrosis and postoperative spondylodiscitis. Causes of readmission are significantly changing at different periods after surgery.
To date, only 12 cases of ossifying arachnoiditis with concomitant syringomyelia have been reported in the world literature. In this article, we presented our experience of treating three patients ...with syringomyelia associated with ossifying arachnoiditis.
based on the literature data and our own experience, we tried to define the most optimal treatment approach for this disease.
We analyzed the data of 15 patients (12 cases reported in the literature and 3 our own cases). The diagnosis was established on the basis of complaints, medical history, patient examination, MRI and CT of the spinal cord, and intraoperative data. Progression of syringomyelia was evaluated by comparison of the neurological status and calculation of the Vaquero index before and after surgery; the Domenicucci classification was used to evaluate the severity of ossifying arachnoiditis. Surgical treatment included several stages: decompressive laminectomy, elimination of spinal cord fixation, excision of ossifying arachnoiditis, shunting of the syrinx, and repair of the dura mater.
An analysis of the patient data reported in the literature (12 cases) and those in our series (3) revealed that in the early postoperative period, 7 (46.7%) of these 15 patients had improvements, 5 (33.3%) patients had no changes, and 3 (20%) patients experienced a worsening. At present, there is no clear algorithm for diagnosing and treating this disease.
Further investigation of the problem may facilitate an earlier diagnosis of the disease and provide more effective medical care.
Overview of the CMD-3 recent results Ryzhenenkov, A E; Akhmetshin, R R; Amirkhanov, A N ...
Journal of physics. Conference series,
04/2020, Letnik:
1526, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The CMD-3 detector started data taking at the electron-positron collider VEPP-2000 in December 2010 with a goal to collect about 1 fb−1. The collected data sample corresponds to an integrated ...luminosity of 200 pb−1 in the center-of-mass energy range from 0.32 up to 2 GeV. This paper reports recent results on the hadronic cross sections measurements with the CMD-3 detector.
We present a study of Michel parameters in leptonic τ decays using experimental information collected at the Belle detector. Michel parameters are extracted in the unbinned maximum likelihood fit of ...the (τ∓→ℓ∓νν; τ±→π±π0ν) (ℓ=e, μ) events in the full nine-dimensional phase space. We exploit the spin-spin correlation of tau leptons to extract ξρξ and ξρξδ in addition to the ρ and η parameters. Sensitivity of the method and systematic effects will be discussed.
Recent results from CMD-3 Ignatov, F. V.; Akhmetshin, R. R.; Amirkhanov, A. N. ...
EPJ Web of Conferences,
2019, Letnik:
212
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
Regular data taking with the CMD-3 at the electron-positron collider VEPP-2000 is under way since 2010. The collected data sample corresponds to about 200 inverse picobarns of integrated luminosity ...per detector in the energy range from 0.32 up to 2 GeV, with a goal to collect about 1
fb
−1
during next five years. Some of the recent results from the CMD-3 detector are discussed.
The results of the experiment on the measurement of the e+e− → π+π− cross section in a cm energy range of 370–520 MeV are presented. The systematic measurement error is equal to 0.7%. In the vector ...dominance model, the pion electromagnetic radius is calculated using all the CMD-2 data on the pion form factor. The cross section for the production of a muon pair is measured in the energy range of the experiment.
Electromagnetic calorimeter for Belle II Belle-ECL; Aulchenko, V; Bobrov, A ...
Journal of physics. Conference series,
01/2015, Letnik:
587, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The electromagnetic calorimeter of the BELLE II detector for experiments at Super B-factory SuperKEKB is briefly described. The project of the calorimeter upgrade to meet severe background conditions ...expected at the upgraded KEK B factory is presented.
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