702 research outputs found
The Physics Case for the New Muon (g-2) Experiment
This White Paper briefly reviews the present status of the muon (g-2)
experiment and the physics motivation for a new effort. The present comparison
between experiment and theory indicates a tantalizing deviation.
An improvement in precision on this comparison by a factor of 2--with the
central value remaining unchanged--will exceed the ``discovery'' threshold,
with a sensitivity above . The 2.5-fold reduction improvement goal of
the new Brookhaven E969 experiment, along with continued steady reduction of
the standard model theory uncertainty, will achieve this more definitive test.
Already, the (g-2) result is arguably the most compelling indicator of
physics beyond the standard model and, at the very least, it represents a major
constraint for speculative new theories such as supersymmetry or extra
dimensions. In this report, we summarize the present experimental status and
provide an up-to-date accounting of the standard model theory, including the
expectations for improvement in the hadronic contributions, which dominate the
overall uncertainty. Our primary focus is on the physics case that motivates
improved experimental and theoretical efforts. Accordingly, we give examples of
specific new-physics implications in the context of direct searches at the LHC
as well as general arguments about the role of an improved (g-2) measurement. A
brief summary of the plans for an upgraded effort complete the report.Comment: 18 pages, 7 figure
A diagrammatic treatment of neutrino oscillations
We present a covariant wave-packet approach to neutrino flavor transitions in
vacuum. The approach is based on the technique of macroscopic Feynman diagrams
describing the lepton number violating processes of production and absorption
of virtual massive neutrinos at the macroscopically separated space-time
regions ("source" and "detector"). Accordingly, the flavor transitions are a
result of interference of the diagrams with neutrinos of different masses in
the intermediate states. The statistically averaged probability of the process
is representable as a multidimensional integral of the product of the factors
which describe the differential flux density of massless neutrinos from the
source, differential cross section of the neutrino interaction with the
detector and a dimensionless factor responsible for the flavor transition. The
conditions are analyzed under which the last factor can be treated as the
flavor transition probability in the usual quantum-mechanical sense.Comment: 27 pages,7 figures, iopart class. Includes minor corrections made in
proofs. References update
Neutrino oscillations and the effect of the finite lifetime of the neutrino source
We consider a neutrino source at rest and discuss a condition for the
existence of neutrino oscillations which derives from the finite lifetime
of the neutrino source particle. This condition is present if the
neutrino source is a free particle such that its wave function is
non-stationary. For a Gaussian wave function and with some simplifying
assumptions, we study the modification of the usual oscillation probability
stemming from . In the present accelerator experiments the effect of
can be neglected. We discuss some experimental situations where the
source lifetime becomes relevant in the oscillation formula.Comment: 13 pages latex file with 2 figure
Effects of neutrino oscillations and neutrino magnetic moments on elastic neutrino-electron scattering
We consider elastic antineutrino-electron scattering taking into account
possible effects of neutrino masses and mixing and of neutrino magnetic moments
and electric dipole moments. Having in mind antineutrinos produced in a nuclear
reactor we compute, in particular, the weak-electromagnetic interference terms
which are linear in the magnetic (electric dipole) moments and also in the
neutrino masses. We show that these terms are, however, suppressed compared to
the pure weak and electromagnetic cross section. We also comment upon the
possibility of using the electromagnetic cross section to investigate neutrino
oscillations.Comment: 12 pages, REVTEX file, no figures, submitted to Phys.Rev.
Object Serialization and Deserialization Using XML
Interoperability of potentially heterogeneous databases has been an ongoing
research issue for a number of years in the database community. With the trend
towards globalization of data location and data access and the consequent
requirement for the coexistence of new data stores with legacy systems, the
cooperation and data interchange between data repositories has become
increasingly important. The emergence of the eXtensible Markup Language (XML)
as a database independent representation for data offers a suitable mechanism
for transporting data between repositories. This paper describes a research
activity within a group at CERN (called CMS) towards identifying and
implementing database serialization and deserialization methods that can be
used to replicate or migrate objects across the network between CERN and
worldwide centres using XML to serialize the contents of multiple objects
resident in object-oriented databases.Comment: 14 pages 7 figure
Applying Control-Value Theory for Examining Multiple Emotions in Second Language Classrooms: Validating the Achievement Emotions Questionnaire-Second Language Learning
This study used Pekrun’s (2006, 2018) control-value theory (CVT) as a framework to validate the Achievement Emotion Questionnaire-Second Language Learning (AEQ-L2L) for assessing eight student emotions in L2 learning. We tested and validated the instrument in two samples using three waves of data, with a total number of 1,021 Chinese university students. Item and scale statistics indicate the AEQ-L2L is reliable. Moreover, single- and multi-group confirmatory factor analysis supported the hierarchical four-factor component structure of L2 emotions in and across the two student groups. Furthermore, multi-model comparison indicated that language emotions are best represented by considering both the distinctiveness of the eight examined emotions and their component structure. Finally, latent correlation analysis demonstrated the external validity of the AEQ-L2L in terms of linkages with appraisals, motivation and language achievement. Findings are discussed by highlighting the unique value of the AEQ-L2L for investigating a broad range of emotions in language education
Preclinical animal acute toxicity studies of new developed MRI contrast agent based on gadolinium
Acute toxicity test of new developed MRI contrast agent based on disodium salt of gadopentetic acid complex were carried out on Mus musculus and Sprague Dawley rats according to guidelines of preclinical studies [1]. Groups of six animals each were selected for experiment. Death and clinical symptoms of animals were recorded during 14 days. As a result the maximum tolerated dose (MTD) for female mice is 2.8 mМ/kg of body weight, male mice - 1.4 mМ/kg, female rats - 2.8 mМ/kg, male rats - 5.6 mМ/kg of body weight. No Observed Adverse Effect Dose (NOAEL) for female mice is 1.4 mМ/kg, male mice - 0.7 mМ/kg, male and female rats - 0.7 mМ/kg. According to experimental data new developed MRI contrast agent based on Gd-DTPA complex is low-toxic
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