A
bstract
B
decays proceeding via
b
→
cℓν
transitions with
ℓ
=
e
or
μ
are tree-level processes in the Standard Model. They are used to measure the CKM element
V
cb
, as such forming an important ...ingredient in the determination of e.g. the unitarity triangle; hence the question to which extent they can be affected by new physics contributions is important, specifically given the long-standing tension between
V
cb
determinations from inclusive and exclusive decays and the significant hints for lepton flavour universality violation in
b
→
cτ ν
and
b
→
sℓℓ
decays. We perform a comprehensive model-independent analysis of new physics in
b
→
cℓν
, considering all combinations of scalar, vector and tensor interactions occuring in single-mediator scenarios. We include for the first time differential distributions of
B
→
D
∗
ℓν
angular observables for this purpose. We show that these are valuable in constraining non-standard interactions. Specifically, the zero-recoil endpoint of the
B
→
Dℓν
spectrum is extremely sensitive to scalar currents, while the maximum-recoil endpoint of the
B
→
D
∗
ℓν
spectrum with transversely polarized
D
∗
is extremely sensitive to tensor currents. We also quantify the room for
e
-
μ
universality violation in
b
→
cℓν
transitions, predicted by some models suggested to solve the
b
→
cτ ν
anomalies, from a global fit to
B
→
Dℓν
and
B
→
D
∗
ℓν
for the first time. Specific new physics models, corresponding to all possible tree-level mediators, are also discussed. As a side effect, we present
V
cb
determinations from exclusive
B
decays, both with frequentist and Bayesian statistics, leading to compatible results. The entire numerical analysis is based on open source code, allowing it to be easily adapted once new data or new form factors become available.
wilson
is a Python library for matching and running Wilson coefficients of higher-dimensional operators beyond the Standard Model. Provided with the numerical values of the Wilson coefficients at a ...high new physics scale, it automatically performs the renormalization group evolution within the Standard Model effective field theory (SMEFT), matching onto the weak effective theory (WET) at the electroweak scale, and QCD/QED renormalization group evolution below the electroweak scale down to hadronic scales relevant for low-energy precision tests. The matching and running encompasses the complete set of dimension-six operators in both SMEFT and WET. The program builds on the Wilson coefficient exchange format (WCxf) and can thus be easily combined with a number of existing public codes.
We present a global likelihood function in the space of dimension-six Wilson coefficients in the Standard Model Effective Field Theory. The likelihood includes contributions from flavour-changing ...neutral current
B
decays, lepton flavour universality tests in charged- and neutral-current
B
and
K
decays, meson-antimeson mixing observables in the
K
,
B
, and
D
systems, direct CP violation in
K
→
π
π
, charged lepton flavour violating
B
, tau, and muon decays, electroweak precision tests on the
Z
and
W
poles, the anomalous magnetic moments of the electron, muon, and tau, and several other precision observables, 265 in total. The Wilson coefficients can be specified at any scale, with the one-loop running above and below the electroweak scale automatically taken care of. The implementation of the likelihood function is based on the open source tools flavio and wilson as well as the open Wilson coefficient exchange format (WCxf) and can be installed as a Python package. It can serve as a basis either for model-independent fits or for testing dynamical models, in particular models built to address the anomalies in
B
physics. We discuss a number of example applications, reproducing results from the EFT and model building literature.
B-decay discrepancies after Moriond 2019 Aebischer, Jason; Altmannshofer, Wolfgang; Guadagnoli, Diego ...
The European physical journal. C, Particles and fields,
03/2020, Letnik:
80, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Following the updated measurement of the lepton flavour universality (LFU) ratio
R
K
in
B
→
K
ℓ
ℓ
decays by LHCb, as well as a number of further measurements, e.g.
R
K
∗
by Belle and
B
s
→
μ
μ
by ...ATLAS, we analyse the global status of new physics in
b
→
s
transitions in the weak effective theory at the
b
-quark scale, in the Standard Model effective theory above the electroweak scale, and in simplified models of new physics. We find that the data continues to strongly prefer a solution with new physics in semi-leptonic Wilson coefficients. A purely muonic contribution to the combination
C
9
=
-
C
10
, well suited to UV-complete interpretations, is now favoured with respect to a muonic contribution to
C
9
only. An even better fit is obtained by allowing an additional LFU shift in
C
9
. Such a shift can be renormalization-group induced from four-fermion operators above the electroweak scale, in particular from semi-tauonic operators, able to account for the potential discrepancies in
b
→
c
transitions. This scenario is naturally realized in the simplified
U
1
leptoquark model. We also analyse simplified models where a LFU effect in
b
→
s
ℓ
ℓ
is induced radiatively from four-quark operators and show that such a setup is on the brink of exclusion by LHC di-jet resonance searches.
A
bstract
A new phase for the measurements of radiative decay modes in
b
→
s
transitions has started with new measurements of exclusive modes by LHCb and with Belle-II showing distinctive promises in ...both inclusive and exclusive channels. After critically reviewing the hadronic uncertainties in exclusive radiative decays, we analyze the impact of recent measurements of the branching ratio and mass-eigenstate rate asymmetry in
B
s
→
ϕγ
and of the angular distribution of
B
→
K
∗
e
+
e
−
at low
q
2
on new physics in the
b
→
s
γ transition.
Purpose
Radiation-induced fibrosis (RIF) is a long-term side effect of external beam radiation therapy for the treatment of cancer. It results in a multitude of symptoms that significantly impact ...quality of life. Understanding the mechanisms of RIF-induced changes is essential to developing effective strategies to prevent long-term disability and discomfort following radiation therapy. In this review, we describe the current understanding of the etiology, clinical presentation, pathogenesis, treatment, and directions of future therapy for this condition.
Methods
A literature review of publications describing mechanisms or treatments of RIF was performed. Specific databases utilized included PubMed and clinicaltrials.gov, using keywords “Radiation-Induced Fibrosis,” “Radiotherapy Complications,” “Fibrosis Therapy,” and other closely related terms.
Results
RIF is the result of a misguided wound healing response. In addition to causing direct DNA damage, ionizing radiation generates reactive oxygen and nitrogen species that lead to localized inflammation. This inflammatory process ultimately evolves into a fibrotic one characterized by increased collagen deposition, poor vascularity, and scarring. Tumor growth factor beta serves as the primary mediator in this response along with a host of other cytokines and growth factors. Current therapies have largely been directed toward these molecular targets and their associated signaling pathways.
Conclusion
Although RIF is widely prevalent among patients undergoing radiation therapy and significantly impacts quality of life, there is still much to learn about its pathogenesis and mechanisms. Current treatments have stemmed from this understanding, and it is anticipated that further elucidation will be essential for the development of more effective therapies.
A new light particle in B decays? Sala, Filippo; Straub, David M.
Physics letters. B,
11/2017, Letnik:
774, Številka:
C
Journal Article
Recenzirano
Odprti dostop
We investigate the possibility whether the tensions with SM expectations observed in several b→sℓℓ transitions, including hints for lepton flavour non-universality, could be due to the decay of B ...into a new light resonance. We find that qualitative agreement with the data can be obtained with a light vector resonance dominantly decaying invisibly. This scenario predicts a shift in the muon anomalous magnetic moment that could explain the long-standing discrepancy. The most stringent constraint comes from searches for B decays with missing energy. A striking prediction is a strong q2 dependence of the lepton flavour universality ratios RK and RK⁎ that should allow to clearly confirm or rule out this possibility experimentally. We also comment on the possible connection of the invisible decay product with Dark Matter.
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