A new high precision measurement of the J/ψ- and ψ′-meson masses has been performed at the VEPP-4M collider using the KEDR detector. The resonant depolarization method has been employed for the ...absolute calibration of the beam energy. The following mass values have been obtained: MJ/ψ=3096.917±0.010±0.007 MeV,Mψ′=3686.111±0.025±0.009 MeV. The relative measurement accuracy has reached 4×10−6 for J/ψ and 7×10−6 for ψ′, approximately 3 times better than in the previous precise experiments.
We report on quantum electrical characteristics of dendritic copper point contacts (PCs) formed through an electrochemical process via a new cyclic switchover effect that is demonstrated by the ...occurrence of steps in the time dependence of the dendritic-PCs conductance. We show that this quantization of the electrical conductance is due to an electronic shell effect governing the dendrite growth. The cyclic variations of conductance during dendritic PCs electrosynthesis offer the possibility for forming nanostructures of preassigned sizes controlled through their electrical resistance.
Particle physics today faces the challenge of explaining the mystery of dark matter, the origin of matter over anti-matter in the Universe, the origin of the neutrino masses, the apparent fine-tuning ...of the electro-weak scale, and many other aspects of fundamental physics. Perhaps the most striking frontier to emerge in the search for answers involves new physics at mass scales comparable to familiar matter, below the GeV-scale, or even radically below, down to sub-eV scales, and with very feeble interaction strength. New theoretical ideas to address dark matter and other fundamental questions predict such feebly interacting particles (FIPs) at these scales, and indeed, existing data provide numerous hints for such possibility. A vibrant experimental program to discover such physics is under way, guided by a systematic theoretical approach firmly grounded on the underlying principles of the Standard Model. This document represents the report of the FIPs 2022 workshop, held at CERN between the 17 and 21 October 2022 and aims to give an overview of these efforts, their motivations, and the decadal goals that animate the community involved in the search for FIPs.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The paper studies the genetic diversity of microorganisms isolated from root nodules of wild populations of the legumes
Lathyrus pratensis
L.,
Vicia cracca
L.,
Trifolium repens
L., and
Astragalus ...schelichowii
Turcz. collected near Norilsk (Arctic Russia). The taxonomic position of the 19 isolates obtained was determined by sequencing the 16S rRNA gene (
rrs
). The isolates were assigned to four genera of the order
Hyphomicrobiales
:
Rhizobium
,
Pararhizobium
,
Bosea
and
Tardiphaga
. Nine fast-growing isolates belonged to the genera
Rhizobium
and
Pararhizobium
. ITS region sequencing clarified the species identity of 6 rhizobial isolates. Isolates from
V. cracca
nodules were identified as
Pararhizobium
sp.,
P. herbae
. Microsymbionts from
T. repens
were assigned to
Rhizobium
sp. and to the species
R. beringeri
, while isolates from
L. pratensis
were identified as
P. herbae
and
R. beringeri
. Symbiotic
nodA
and
nodC
genes were found in the
Rhizobium
strains P8/5-2, P9/1-1 and P9/3-2 from
L. pratensis
and
T. repens
nodules,
nodA
gene was detected in the
Pararhizobium
strains P7/3-1, P7/4-1, P7/5-1 from
V. cracca
nodules. Nine out of ten slow-growing isolates were assigned to the genus
Bosea
. Three isolates from the nodules of
V. cracca
were assigned to the species
B. psychrotolerans
. Six isolates from the nodules of
A. schelichowii
were identified as
B. vaviloviae
,
B. lathyri
and
Bosea
sp. The strain P22/3-5 isolated from the nodule of
A. schelichowii
was identified as
Tardiphaga robiniae
. Simultaneous presence of strains belonging to different genera of the order
Hyphomicrobiales
was detected in the nodules of
V. cracca
and
A. schelichowii.
The paper considers various compensating devices of power system network parameters. A special attention has been given to controlled flexible power lines and control over them.
The paper considers longitudinal and lateral compensation of a.c. power line parameters. It is shown that controlled and shunt reactor creates controlled longitudinal compensation.
In the present study, chitosan coatings modified with g-C
3
N
4
were prepared for AZ91 magnesium alloy. The microstructure of the chitosan–g-C
3
N
4
coatings, depending on the concentration of the ...particles of the modifying phase in the chitosan solution, was investigated by scanning electron microscopy and X-ray phase analysis. It was found that coatings prepared in suspension of chitosan containing more than 30 g/dm
3
g-C
3
N
4
exhibited a complete wettability with a sodium-phosphate buffer solution. Confocal microscopy established the degree of inhibition of E. coli biofilm formation on the surface of the prepared coatings. It was found by using linear voltammetry and electrochemical impedance spectroscopy that the modification of chitosan by the g-C
3
N
4
particles led to an improvement in the protective properties of coatings.
Flavor physics of leptons and dipole moments Raidal, M.; van der Schaaf, A.; Bigi, I. ...
European physical journal. C, Particles and fields (Print),
09/2008, Letnik:
57, Številka:
1-2
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
This chapter of the report of the “Flavor in the era of the LHC” Workshop discusses the theoretical, phenomenological and experimental issues related to flavor phenomena in the charged lepton sector ...and in flavor conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavor structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the standard model, presenting benchmarks for the discovery potential of forthcoming measurements both at the LHC and at low energy, and exploring options for possible future experiments.
This letter reports on a search for hypothetical heavy neutrinos,
N
, and right-handed gauge bosons,
W
R
, in events with high transverse momentum objects which include two reconstructed leptons and ...at least one hadronic jet. The results were obtained from data corresponding to an integrated luminosity of 2.1 fb
−1
collected in proton–proton collisions at
with the ATLAS detector at the CERN Large Hadron Collider. No excess above the Standard Model background expectation is observed. Excluded mass regions for Majorana and Dirac neutrinos are presented using two approaches for interactions that violate lepton and lepton-flavor numbers. One approach uses an effective operator framework, the other approach is guided by the Left–Right Symmetric Model. The results described in this letter represent the most stringent limits to date on the masses of heavy neutrinos and
W
R
bosons obtained in direct searches.
This paper presents a search for the
t
-channel exchange of an
R
-parity violating scalar top quark (
) in the
e
±
μ
∓
continuum using 2.1 fb
−1
of data collected by the ATLAS detector in
pp
...collisions at the Large Hadron Collider. Data are found to be consistent with the expectation from the Standard Model backgrounds. Limits on
R
-parity-violating couplings at 95 % C.L. are calculated as a function of the scalar top mass (
). The upper limits on the production cross section for
pp
→
eμX
, through the
t
-channel exchange of a scalar top quark, ranges from 170 fb for
to 30 fb for
.
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