64 research outputs found
Non-commutative SU(N) gauge theories and asymptotic freedom
In this paper we analyze the one-loop renormalization of the
-expanded Yang-Mills theory. We show that the {\it freedom
parameter} , key to renormalization, originates from higher order
non-commutative gauge interaction, represented by a higher derivative term . The renormalization condition fixes the allowed values of the
parameter to one of the two solutions: or , i.e. to or to
, respectively. When the higher order interaction is switched on,
(), pure non-commutative SU(N) gauge theory at first order in
-expansion becomes one-loop renormalizable for various representations
of the gauge group. We also show that, in the case and the adjoint
representation of the gauge fields, the non-commutative deformation parameter
has to be renormalized and it is asymptotically free.Comment: 16 pages, no figure
The one-loop renormalization of the gauge sector in the noncommutative standard model
In this paper we construct a version of the standard model gauge sector on
noncommutative space-time which is one-loop renormalizable to first order in
the expansion in the noncommutativity parameter . The one-loop
renormalizability is obtained by the Seiberg-Witten redefinition of the
noncommutative gauge potential for the model containing the usual six
representations of matter fields of the first generation.Comment: 16 pages, 2 figure
Renormalizability of noncommutative SU(N) gauge theory
We analyze the renormalizability properties of pure gauge noncommutative
SU(N) theory in the -expanded approach. We find that the theory is
one-loop renormalizable to first order in .Comment: 11 pages, minor changes, accepted for publication in JHE
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Psychometric properties of the Serbian Smartphone Application-Based Addiction Scale (SABAS) and validation of the English version among non-native English speakers problematic smartphone use and smartphone addiction
The present study evaluated the psychometric properties of the Serbian Smartphone Application-Based Addiction Scale (SABAS) and the original English version of the same scale administered to a Serbian-speaking sample. In Study 1, 599 participants completed Serbian SABAS, with 189 having both test and retest data. Results suggested good internal consistency (α = .81) and test–retest reliability (ICC = .795, p < .001, 95% CI [.731, .844], rtest-retest = .803) of the scale. Convergent validity of the SABAS was evaluated through correlations with the Smartphone Addiction Scale–Short Version (SAS-SV), as well as with anxiety, depression, worry, duration, and purpose of smartphone use. Divergent validity of the SABAS was evaluated through comparing the correlations with entertainment and productive smartphone use. The modified CFA model showed an acceptable fit (χ2(8) = 25.53, p = .001, CFI = .961, TLI = .926, RMSEA = .096, SRMR = .042), confirming the unidimensionality of the SABAS. In the second study, the English SABAS, completed by 335 non-native speakers from Serbia, also showed a good fit of the single-factor model (χ2(9) = 12.56, p = .184, CFI = .990, TLI = .984, RMSEA = .036, SRMR = 0.026), and good psychometric features. Based on the study’s findings, the Serbian version of SABAS is a reliable and valid measure for screening the risk of smartphone addiction. Moreover, the English version can be used among non-native Serbian English speakers
The absence of the 4 divergence in noncommutative chiral models
In this paper we show that in the noncommutative chiral gauge theories the
4-fermion vertices are finite. The -vertices appear in linear order in
quantization of the -expanded noncommutative gauge theories; in all
previously considered models, based on Dirac fermions, the -vertices
were divergent and nonrenormalizable.Comment: 7 page
Factors affecting consistency and accuracy in identifying modern macroperforate planktonic foraminifera
Planktonic foraminifera are widely used in biostratigraphic, palaeoceanographic and evolutionary studies, but the strength of many study conclusions could be weakened if taxonomic identifications are not reproducible by different workers. In this study, to assess the relative importance of a range of possible reasons for among-worker disagreement in identification, 100 specimens of 26 species of macroperforate planktonic foraminifera were selected from a core-top site in the subtropical Pacific Ocean. Twenty-three scientists at different career stages – including some with only a few days experience of planktonic foraminifera – were asked to identify each specimen to species level, and to indicate their confidence in each identification. The participants were provided with a species list and had access to additional reference materials. We use generalised linear mixed-effects models to test the relevance of three sets of factors in identification accuracy: participant-level characteristics (including experience), species-level characteristics (including a participant’s knowledge of the species) and specimen-level characteristics (size, confidence in identification). The 19 less experienced scientists achieve a median accuracy of 57 %, which rises to 75 % for specimens they are confident in. For the 4 most experienced participants, overall accuracy is 79 %, rising to 93 % when they are confident. To obtain maximum comparability and ease of analysis, everyone used a standard microscope with only 35× magnification, and each specimen was studied in isolation. Consequently, these data provide a lower limit for an estimate of consistency. Importantly, participants could largely predict whether their identifications were correct or incorrect: their own assessments of specimen-level confidence and of their previous knowledge of species concepts were the strongest predictors of accuracy
TeV Scale Implications of Non Commutative Space time in Laboratory Frame with Polarized Beams
We analyze , and processes within the
Seiberg-Witten expanded noncommutative scenario using polarized beams. With
unpolarized beams the leading order effects of non commutativity starts from
second order in non commutative(NC) parameter i.e. , while with
polarized beams these corrections appear at first order () in cross
section. The corrections in Compton case can probe the magnetic
component() while in Pair production and Pair annihilation
probe the electric component() of NC parameter. We include the
effects of earth rotation in our analysis. This study is done by investigating
the effects of non commutativity on different time averaged cross section
observables. The results which also depends on the position of the collider,
can provide clear and distinct signatures of the model testable at the
International Linear Collider(ILC).Comment: 22 pages, 19 figures, new comments and references added, few typos
corrected, Published in JHE
On UV/IR mixing in noncommutative gauge field theories
In formulating gauge field theories on noncommutative (NC) spaces it is
suggested that particles carrying gauge invariant quantities should not be
viewed as pointlike, but rather as extended objects whose sizes grow linearly
with their momenta. This and other generic properties deriving from the
nonlocal character of interactions (showing thus unambiguously their
quantum-gravity origin) lead to a specific form of UV/IR mixing as well as to a
pathological behavior at the quantum level when the noncommutativity parameter
theta is set to be arbitrarily small. In spite of previous suggestions that in
a NC gauge theory based on the theta-expanded Seiberg-Witten (SW) maps UV/IR
mixing effects may be under control, a fairly recent study of photon
self-energy within a SW theta-exact approach has shown that UV/IR mixing is
still present. We study the self-energy contribution for neutral fermions in
the theta-exact approach of NC QED, and show by explicit calculation that all
but one divergence can be eliminated for a generic choice of the
noncommutativity parameter theta. The remaining divergence is linked to the
pointlike limit of an extended object.Comment: 10 pages, a figure added, version to appear in JHE
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