88,646 research outputs found
Consequences of R-Parity violating interactions for anomalies in and
We investigate the possibility of explaining the enhancement in semileptonic
decays of , the anomalies induced by in and violation of lepton
universality in
within the framework of R-parity violating (RPV) MSSM. Exchange of down type
right-handed squark coupled to quarks and leptons yield interactions which are
similar to leptoquark induced interactions that have been proposed to explain
the by tree level interactions and anomalies by loop induced interactions, simultaneously. However,
the Yukawa couplings in such theories have severe constraints from other rare
processes in and decays. Although this interaction can provide a viable
solution to anomaly, we show that with the severe constraint from
, it is impossible to solve the anomalies in process simultaneously.Comment: RevTex, 13 pages, three figures. In our earlier version, we had
neglected a contribution to C^{NP}_9 and obtained erroneous conclusions which
we have corrected them in this versio
Triple Neutral Gauge Boson Couplings in Noncommutative Standard Model
It has been shown recently that the triple neutral gauge boson couplings are
not uniquely determined in noncommutative extension of the Standard Model
(NCSM). Depending on specific schemes used, the couplings are different and may
even be zero. To distinguish different realizations of the NCSM, additional
information either from theoretical or experimental considerations is needed.
In this paper we show that these couplings can be uniquely determined from
considerations of unification of electroweak and strong interactions. Using
SU(5) as the underlying theory and integrating out the heavy degrees of
freedom, we obtain unique non-zero new triple , , , , , and couplings at the
leading order in the NCSM. We also briefly discuss experimental implications.Comment: 8 pages, Latex, no figur
S-OHEM: Stratified Online Hard Example Mining for Object Detection
One of the major challenges in object detection is to propose detectors with
highly accurate localization of objects. The online sampling of high-loss
region proposals (hard examples) uses the multitask loss with equal weight
settings across all loss types (e.g, classification and localization, rigid and
non-rigid categories) and ignores the influence of different loss distributions
throughout the training process, which we find essential to the training
efficacy. In this paper, we present the Stratified Online Hard Example Mining
(S-OHEM) algorithm for training higher efficiency and accuracy detectors.
S-OHEM exploits OHEM with stratified sampling, a widely-adopted sampling
technique, to choose the training examples according to this influence during
hard example mining, and thus enhance the performance of object detectors. We
show through systematic experiments that S-OHEM yields an average precision
(AP) improvement of 0.5% on rigid categories of PASCAL VOC 2007 for both the
IoU threshold of 0.6 and 0.7. For KITTI 2012, both results of the same metric
are 1.6%. Regarding the mean average precision (mAP), a relative increase of
0.3% and 0.5% (1% and 0.5%) is observed for VOC07 (KITTI12) using the same set
of IoU threshold. Also, S-OHEM is easy to integrate with existing region-based
detectors and is capable of acting with post-recognition level regressors.Comment: 9 pages, 3 figures, accepted by CCCV 201
A Study of Some Methods for Measuring CKM CP Violating Phases
We study the influence of penguin (especially, electroweak penguin) effects
on some methods of measuring the angles , , and in the
CKM unitarity triangle. We use next-to-leading order effective Hamiltonian, and
present numerical estimates based on the factorization approximation. We find
that some techniques suggested in the literature, especially for
determination, are not workable in light of the electroweak penguin effects.
Nevertheless, there are methods that would work for each angle determination.
For angle we consider mode and estimate the
penguin contamination. For angle we consider a method based on SU(3)
symmetry and carefully consider SU(3) breaking effects. We point out regions in
the parameter space where this method could be used reliably.Comment: 25 pages (Latex), 5 PS figs (uuencoded, epsf.tex
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