2,430 research outputs found
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
Rare K and B Decays in a Warped Extra Dimension with Custodial Protection
We present a complete study of rare K and B meson decays in a warped extra
dimensional model with a custodial protection of (both diagonal and
non-diagonal) Z d_L^i \bar d_L^j couplings, including K^+ -> pi^+ nu anti-nu,
K_L -> pi^0 nu anti-nu, K_L -> pi^0 l^+ l^-, K_L -> mu^+ mu^-, B_{s,d} -> mu^+
mu^-, B -> K nu anti-nu, B -> K^* nu anti-nu and B -> X_{s,d} nu anti-nu. In
this model in addition to Standard Model one loop contributions these processes
receive tree level contributions from the Z boson and the new heavy electroweak
gauge bosons. We analyse all these contributions that turn out to be dominated
by tree level Z boson exchanges governed by right-handed couplings to down-type
quarks. Imposing all existing constraints from Delta F=2 transitions analysed
by us recently and fitting all quark masses and CKM mixing parameters we find
that a number of branching ratios for rare K decays can differ significantly
from the SM predictions, while the corresponding effects in rare B decays are
modest, dominantly due to the custodial protection being more effective in B
decays than in K decays. In order to reduce the parameter dependence we study
correlations between various observables within the K system, within the B
system and in particular between K and B systems, and also between Delta F=2
and Delta F=1 observables. These correlations allow for a clear distinction
between this new physics scenario and models with minimal flavour violation or
the Littlest Higgs Model with T-parity, and could give an opportunity to future
experiments to confirm or rule out the model. We show how our results would
change if the custodial protection of Z d_L^i bar d^j_L couplings was absent.
In the case of rare B decays the modifications are spectacular.Comment: 50 pages, 17 figures. v2: minor clarifying comments and references
added. v3: few clarifying comments added, matches published versio
Top quark chromomagnetic dipole moment in the littlest Higgs model with T-parity
The littlest Higgs model with T-parity, which is called model, predicts
the existence of the new particles, such as heavy top quark, heavy gauge
bosons, and mirror fermions. We calculate the one-loop contributions of these
new particles to the top quark chromomagnetic dipole moment . We find that the contribution of the model is one order of magnitude
smaller than the standard model prediction value.Comment: latex files, 12 pages, 3 figure
Brief review of the searches for the rare decays and
The current experimental status of the searches for the very rare decays
and is discussed.
These channels are highly sensitive to various extensions of the Standard
Model, specially in the scalar and pseudoscalar sector. The recent, most
sensitive measurements from the CDF, ATLAS, CMS and LHCb collaborations are
discussed and the combined upper exclusion limit on the branching fractions
determined by the LHC experiments is shown to be for and for . The implications of these tight bounds on a selected set of New Physics
models is sketched.Comment: 20 pages, 15 figures, invited review for Modern Physics Letters
Transitions in Family-dependent Models
We analyze flavor-changing-neutral-current (FCNC) effects in the
transitions that are induced by family non-universal gauge symmetries.
After systematically developing the necessary formalism, we present a
correlated analysis for the processes. We adopt a
model-independent approach in which we only require family-universal charges
for the first and second generations and small fermion mixing angles. We
analyze the constraints on the resulting parameter space from
mixing and the time-dependent CP asymmetries of the penguin-dominated decays. Our results indicate that the
currently observed discrepancies in some of these modes with respect to the
Standard Model predictions can be consistently accommodated within this general
class of models.Comment: 36 pages, 11 figure
Frank Miller’s Sin City College Football: A Game to Die For And Other Lessons About the Right of Publicity and Video Games
The challenge of finding a workable solution for applying the right of publicity is a formidable one because it implicates not only a delicate balance between First Amendment rights and the rights of publicity, but also the complications of varying state laws. The best of the tests developed by the courts so far—the transformative use test—was borrowed from copyright law and itself reflects a careful balance between First Amendment and copyright interests. Additionally, because of dramatic progress in technology, it is likely that in the near future this balancing will often involve not only the rights of publicity and the First Amendment but also copyright law as well
Privacy and Outrage
It is not an understatement that technology has dramatically altered virtually every aspect of our life in recent years. While technology has always driven change, these changes are occurring more rapidly and more extensively than ever before. We are fully entrenched in the world of Big Data, the Internet of Things, and Smart Cities – and we are never going back. As always, society and its laws must evolve, but it is not always an easy process.
The notion of privacy has certainly changed in our data-driven world and continues to change daily. While it has always been difficult to define exactly what privacy is, it is even more difficult to propose what privacy should become. Technology and its uses – or abuses – are altering the notion of privacy into something that may be unrecognizable in the near future.
Studies show that people say they are still concerned about privacy, but their behavior does not reflect that.1 Like any value, the importance of privacy varies from person to person. This makes it even more difficult to establish a one-sizefits-all concept of privacy. This paper explores some of the historical, legal, and ethical development of privacy; discusses how some of the normative values of privacy may survive or change; and examines how outrage has been – and will continue to be – a driver of such change
Minimal Flavour Violation and Beyond
Starting from the effective-theory framework for Minimal Flavour Violation,
we give a systematic definition of next-to-minimal (quark) flavour violation in
terms of a set of spurion fields exhibiting a particular hierarchy with respect
to a small (Wolfenstein-like) parameter. A few illustrative examples and their
consequences for charged and neutral decays with different quark chiralities
are worked out in some detail. Our framework can be used as a model-independent
classification scheme for the parameterization of flavour structure from
physics beyond the Standard Model.Comment: 17 pages, no figures, phenomenological discussion extended,
references adde
Electroweak and Flavour Structure of a Warped Extra Dimension with Custodial Protection
We present the electroweak and flavour structure of a model with a warped
extra dimension and the bulk gauge group SU(3) x SU(2)_L x SU(2)_R x P_LR x
U(1)_X. The presence of SU(2)_R implies an unbroken custodial symmetry in the
Higgs system allowing to eliminate large contributions to the T parameter,
whereas the P_LR symmetry and the enlarged fermion representations provide a
custodial symmetry for flavour diagonal and flavour changing couplings of the
SM Z boson to left-handed down-type quarks. We diagonalise analytically the
mass matrices of charged and neutral gauge bosons including the first KK modes.
We present the mass matrices for quarks including heavy KK modes and discuss
the neutral and charged currents involving light and heavy fields. We give the
corresponding complete set of Feynman rules in the unitary gauge.Comment: 74 pages, 2 figures. clarifying comments and references added,
version to be published in JHE
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