9,871 research outputs found
New Physics Signatures in Kaon Decays
Kaon physics provides a unique opportunity to identify new flavour and CP
violating interactions beyond the Standard Model (SM). In the SM, implied by
the hierarchical structure of the CKM matrix and the GIM mechanism, flavour
changing neutral current processes are most strongly suppressed in the kaon
sector while the suppression is much less effective in the B meson systems.
Thus their theoretical cleanness makes rare K decays, in particular the K -> pi
nu anti-nu system, extremely well suited to look for deviations from their tiny
SM values. Despite the increasingly stringent constraints on new physics from
direct search experiments as well as indirect searches in B meson decays, large
enhancements of both K^+ -> pi^+ nu anti-nu and K_L -> pi^0 nu anti-nu are
still possible, and deviations from the SM could be observed even for a
multi-TeV new physics scale. In addition the correlation betweeen the charged
and neutral K -> pi nu anti-nu modes provides insight on the new physics
operator structure in K^0 - anti-K^0 mixing and its interplay with rare K
decays. Useful model-discriminating correlations exist also in the K_L -> pi^0
l^+ l^- system. Finally the K -> l nu decays provide a clean test of lepton
universality and place constraints on new physics complementary to the ones
obtained from the searches for charged lepton flavour violating decays.Comment: 10 pages, 7 figures. Proceedings for KAON13 - 2013 Kaon Physics
International Conference at the University of Michigan, Ann Arbor, April
29-May 1 201
Phenomenological aspects of flavoured dark matter
Flavour symmetries in the dark sector are a theoretically motivated and
phenomenologically appealing concept. The dark matter particle can be
stabilised with the help of flavour symmetries, without the need to introduce
an additional discrete symmetry by hand. Apart from the usual searches in
direct and indirect detection experiments and high energy colliders, flavoured
dark matter generally also gives rise to new flavour violating interactions
leading to interesting signatures in rare meson decays. This proceedings
article reviews a simplified model of flavoured dark matter in which the dark
matter coupling to quarks constitutes a new source of flavour violation, so
that the model goes beyond Minimal Flavour Violation. Particular emphasis is
put on the discussion of its phenomenological implications in flavour, collider
and direct detection experiments.Comment: 7 pages, proceedings of The European Physical Society Conference on
High Energy Physics, 22-29 July 2015, Vienna, Austri
Quo vadis flavour physics? - FPCP2017 theory summary and outlook
We review the recent highlights of theoretical flavour physics, based on the
theory summary talk given at FPCP2017. Over the past years, a number of
intriguing anomalies have emerged in flavour violating and meson
decays, constituting some of the most promising hints for the presence of
physics beyond the Standard Model. We discuss the theory status of these
anomalies and outline possible future directions to test the underlying New
Physics.Comment: 15 pages, 4 figures. Proceedings for FPCP2017, 5-9 June 2017, Prague.
v2: references added, final version to appear in Po
Introduction to Flavour Physics and CP Violation
These lecture notes provide an introduction to the theoretical concepts of
flavour physics and CP violation, based on a series of lectures given at the
ESHEP 2016 summer school. In the first lecture we review the basics of flavour
and CP violation in the Standard Model. The second lecture is dedicated to the
phenomenology of K and B meson decays, where we focus on a few representative
observables. In the third lecture we give an introduction to flavour physics
beyond the Standard Model, both within the framework of Minimal Flavour
Violation and beyond.Comment: 30 pages, 10 figures. v2: Few references added. Lectures given at the
ESHEP 2016 summer school in Skeikampen, Norway, 15-28 June 2016. To be
published as CERN Yellow Repor
CP Violation in D0 - anti-D0 Oscillations: General Considerations and Applications to the Littlest Higgs Model with T-Parity
The observed D0 - anti-D0 oscillations provide a new stage in our search for
New Physics in heavy flavour dynamics. The theoretical verdict on the observed
values of x_D and y_D remains ambiguous: while they could be totally generated
by Standard Model dynamics, they could also contain a sizable or even leading
contribution from New Physics. Those oscillations are likely to enhance the
observability of CP violation as clear manifestations of New Physics. We
present general formulae for D0 - anti-D0 oscillations, concentrating on the
case of negligible direct CP violation. In particular we derive a general
formula for the time-dependent mixing-induced CP asymmetry in decays to a CP
eigenstate and its correlation with the semileptonic CP asymmetry a_SL(D0) in
D0(t) -> l nu K. We apply our formalism to the Littlest Higgs model with
T-parity, using the time-dependent CP asymmetry in D -> K_S phi as an example.
We find observable effects at a level well beyond anything possible with CKM
dynamics. Comparisons with CP violation in the K and B systems offer an
excellent test of this scenario and reveal the specific pattern of flavour and
CP violation in the D0 - anti-D0 system predicted by this model. We discuss a
number of charm decays that could potentially offer an insight in the dynamics
of CP violation in D decays. We also apply our formalism to B_s - anti-B_s
mixing.Comment: 26 pages, 9 png figures, 1 table. v2: eq. (A.1) corrected, minor
clarifying comments and few references added. v3: typos corrected, matches
published versio
Effect of calcified seaweed application on grazing preference by dairy cows
This report was presented at the UK Organic Research 2002 Conference. An experiment was carried out to determine whether the application of calcified seaweed improved the preference of organic dairy cows for pasture. Two treatments were applied in May 2001; calcified seaweed applied at 625kg/ha (C+) or no application (C-). The number of cows grazing within individual plots was recorded in July and August 2001. A significantly higher number of cows were recorded in C+ plots than in C- plots. This effect could not be explained by changes in soil or herbage analysis. There may have been additional unknown effects of the C+ treatment on herbage palatability but the results may also have been influenced by external factors such as the location of water troughs
Global smoothness estimation of a Gaussian process from regular sequence designs
We consider a real Gaussian process having a global unknown smoothness
,
r_{\scriptscriptstyle 0}\in \mathds{N}_0 and , with (the mean-square derivative of
if ) supposed to be locally stationary with
index . From the behavior of quadratic variations
built on divided differences of , we derive an estimator of
based on - not
necessarily equally spaced - observations of . Various numerical studies of
these estimators exhibit their properties for finite sample size and different
types of processes, and are also completed by two examples of application to
real data.Comment: 28 page
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