4,040 research outputs found
Fusing deep learned and hand-crafted features of appearance, shape, and dynamics for automatic pain estimation
Automatic continuous time, continuous value assessment of a patient's pain from face video is highly sought after by the medical profession. Despite the recent advances in deep learning that attain impressive results in many domains, pain estimation risks not being able to benefit from this due to the difficulty in obtaining data sets of considerable size. In this work we propose a combination of hand-crafted and deep-learned features that makes the most of deep learning techniques in small sample settings. Encoding shape, appearance, and dynamics, our method significantly outperforms the current state of the art, attaining a RMSE error of less than 1 point on a 16-level pain scale, whilst simultaneously scoring a 67.3% Pearson correlation coefficient between our predicted pain level time series and the ground truth
More Benefits of Semileptonic Rare B Decays at Low Recoil: CP Violation
We present a systematic analysis of the angular distribution of Bbar ->
Kbar^\ast (-> Kbar pi) l^+ l^- decays with l = e, mu in the low recoil region
(i.e. at high dilepton invariant masses of the order of the mass of the
b-quark) to account model-independently for CP violation beyond the Standard
Model, working to next-to-leading order QCD. From the employed heavy quark
effective theory framework we identify the key CP observables with reduced
hadronic uncertainties. Since some of the CP asymmetries are CP-odd they can be
measured without B-flavour tagging. This is particularly beneficial for
Bbar_s,B_s -> phi(-> K^+ K^-) l^+ l^- decays, which are not self-tagging, and
we work out the corresponding time-integrated CP asymmetries. Presently
available experimental constraints allow the proposed CP asymmetries to be
sizeable, up to values of the order ~ 0.2, while the corresponding Standard
Model values receive a strong parametric suppression at the level of O(10^-4).
Furthermore, we work out the allowed ranges of the short-distance (Wilson)
coefficients C_9,C_10 in the presence of CP violation beyond the Standard Model
but no further Dirac structures. We find the Bbar_s -> mu^+ mu^- branching
ratio to be below 9*10^-9 (at 95% CL). Possibilities to check the performance
of the theoretical low recoil framework are pointed out.Comment: 18 pages, 3 fig.; 1 reference and comment on higher order effects
added; EOS link fixed. Minor adjustments to Eqs 4.1-4.3 to match the (lower)
q^2-cut as given in paper. Main results and conclusions unchanged; v3+v4:
treatment of exp. uncert. in likelihood-function in EOS fixed and constraints
from scan on C9,C10 updated (Fig 2,3 and Eqs 3.2,3.3). Main results and
conclusions absolutely unchange
Complete Anatomy of B -> K*ll and its angular distribution
We present a complete and optimal set of observables for the exclusive 4-body
B meson decay B -> K*(->K pi) l+l- in the low dilepton mass region, that
contains a maximal number of clean observables. This basis of observables is
built in a systematic way. We show that all the previously defined observables
and any observable that one can construct, can be expressed as a function of
this basis. This set of observables contains all the information that can be
extracted from the angular distribution in the cleanest possible way. We
provide explicit expressions for the full and the uniangular distributions in
terms of this basis. The conclusions presented here can be easily extended to
the large-q^2 region. We study the sensitivity of the observables to
right-handed currents and scalars. Finally, we present for the first time all
the symmetries of the full distribution including massive terms and scalar
contributions.Comment: 37 pages, 12 Figures. Corrected typo in Eqs. (29) and (44). Results
and conclusions unchange
Exploring New Physics in the C7-C7' plane
The Wilson coefficient C7 governing the radiative electromagnetic decays of B
meson has been calculated to a very high accuracy in the Standard Model, but
experimental bounds on either the magnitude or the sign of C7 are often
model-dependent. In the present paper, we attempt at constraining both the
magnitude and sign of C7 using a systematic approach. We consider already
measured observables like the branching ratios of B \rightarrow Xs mu+ mu- and
B \rightarrow Xs gamma, the isospin and CP asymmetries in B \rightarrow K*
gamma, as well as AFB and FL in B \rightarrow K*l+l-. We also discuss the
transverse observable AT2 which, once measured, may help to disentangle some of
the scenarios considered. We explore the constraints on C7, C9, C10 as well as
their chirality-flipped counterparts. Within our framework, we find that we
need to extend the constraints up to 1.6 sigma to allow for the "flipped-sign
solution" of C7. The SM solution for C7 exhibits a very mild tension if New
Physics is allowed in dipole operators only. We provide semi-numerical
expressions for all these observables as functions of the relevant Wilson
coefficients at the low scale.Comment: 54 pages, 16 figures, 15 tables. Normalization factor introduced for
the integrated AFB and FL in Sec.2.5 (Eq.2.35-2.38). Conclusions unchanged.
Not updated in JHE
Implications from clean observables for the binned analysis of B -> K*ll at large recoil
We perform a frequentist analysis of q^2-dependent B-> K*(->Kpi)ll angular
observables at large recoil, aiming at bridging the gap between current
theoretical analyses and the actual experimental measurements. We focus on the
most appropriate set of observables to measure and on the role of the
q^2-binning. We highlight the importance of the observables P_i exhibiting a
limited sensitivity to soft form factors for the search for New Physics
contributions. We compute predictions for these binned observables in the
Standard Model, and we compare them with their experimental determination
extracted from recent LHCb data. Analyzing b->s and b->sll transitions within
four different New Physics scenarios, we identify several New Physics benchmark
points which can be discriminated through the measurement of P_i observables
with a fine q^2-binning. We emphasise the importance (and risks) of using
observables with (un)suppressed dependence on soft form factors for the search
of New Physics, which we illustrate by the different size of hadronic
uncertainties attached to two related observables (P_1 and S_3). We illustrate
how the q^2-dependent angular observables measured in several bins can help to
unravel New Physics contributions to B-> K*(->Kpi)ll, and show the
extraordinary constraining power that the clean observables will have in the
near future. We provide semi-numerical expressions for these observables as
functions of the relevant Wilson coefficients at the low scale.Comment: 50 pages, 21 figures. Improved form factor analysis, conclusions
unchanged. Plots with full resolution. Version published in JHE
Supersymmetric constraints from Bs -> mu+mu- and B -> K* mu+mu- observables
We study the implications of the recent LHCb limit and results on Bs ->
mu+mu- and B -> K* mu+mu- observables in the constrained SUSY scenarios. After
discussing the Standard Model predictions and carefully estimating the
theoretical errors, we show the constraining power of these observables in
CMSSM and NUHM. The latest limit on BR(Bs -> mu+mu-), being very close to the
SM prediction, constrains strongly the large tan(beta) regime and we show that
the various angular observables from B -> K* mu+mu- decay can provide
complementary information in particular for moderate tan(beta) values.Comment: 30 pages, 14 figure
The Benefits of B ---> K* l+ l- Decays at Low Recoil
Using the heavy quark effective theory framework put forward by Grinstein and
Pirjol we work out predictions for B -> K* l+ l-, l = (e, mu), decays for a
softly recoiling K*, i.e., for large dilepton masses sqrt{q^2} of the order of
the b-quark mass m_b. We work to lowest order in Lambda/Q, where Q = (m_b,
sqrt{q^2}) and include the next-to-leading order corrections from the charm
quark mass m_c and the strong coupling at O(m_c^2/Q^2, alpha_s). The leading
Lambda/m_b corrections are parametrically suppressed. The improved Isgur-Wise
form factor relations correlate the B -> K* l+ l- transversity amplitudes,
which simplifies the description of the various decay observables and provides
opportunities for the extraction of the electroweak short distance couplings.
We propose new angular observables which have very small hadronic
uncertainties. We exploit existing data on B -> K* l+ l- distributions and show
that the low recoil region provides powerful additional information to the
large recoil one. We find disjoint best-fit solutions, which include the
Standard Model, but also beyond-the-Standard Model ones. This ambiguity can be
accessed with future precision measurements.Comment: 31 pages, 8 figures; Instability near minimal recoil from numerics
removed, Fig. 1 replaced and minor shifts in short distance uncertainties in
SM predictions; typos corrected and references added; main results and
conclusions unchange
On the Universality of CP Violation in Delta F = 1 Processes
We show that new physics which breaks the left-handed SU(3)_Q quark flavor
symmetry induces contributions to CP violation in Delta F = 1 couplings which
are approximately universal, in that they are not affected by flavor rotations
between the up and the down mass bases. (Only the short distance contributions
are universal, while observables are also affected by hadronic matrix
elements.) Therefore, such flavor violation cannot be aligned, and is
constrained by the strongest bound from either the up or the down sectors. We
use this result to show that the bound from eps'/eps prohibits an SU(3)_Q
breaking explanation of the recent LHCb evidence for CP violation in D meson
decays. Another consequence of this universality is that supersymmetric
alignment models with a moderate mediation scale are consistent with the data,
and are harder to probe via CP violating observables. With current constraints,
therefore, squarks need not be degenerate. However, future improvements in the
measurement of CP violation in D-Dbar mixing will start to probe alignment
models.Comment: 10 pages, 2 figures. Clarifications and references adde
Bayesian Fit of Exclusive Decays: The Standard Model Operator Basis
We perform a model-independent fit of the short-distance couplings
within the Standard Model set of and operators. Our analysis of , and decays is the first to harness the full
power of the Bayesian approach: all major sources of theory uncertainty
explicitly enter as nuisance parameters. Exploiting the latest measurements,
the fit reveals a flipped-sign solution in addition to a Standard-Model-like
solution for the couplings . Each solution contains about half of the
posterior probability, and both have nearly equal goodness of fit. The Standard
Model prediction is close to the best-fit point. No New Physics contributions
are necessary to describe the current data. Benefitting from the improved
posterior knowledge of the nuisance parameters, we predict ranges for currently
unmeasured, optimized observables in the angular distributions of .Comment: 42 pages, 8 figures; v2: Using new lattice input for f_Bs,
considering Bs-mixing effects in BR[B_s->ll]. Main results and conclusion
unchanged, matches journal versio
New physics reach of the decay mode
We present a complete method to construct QCD-protected observables based on
the exclusive 4-body -meson decay in
the low dilepton mass region. The core of the method is the requirement that
the constructed quantities should fulfil the symmetries of the angular
distribution. We have identified all symmetries of the angular distribution in
the limit of massless leptons and explore: a new non-trivial relation between
the coefficients of the angular distribution, the possibility to fully solve
the system for the amplitudes, and the construction of non-trivial
observables. We also present a phenomenological analysis of the new physics
sensitivity of angular observables in the decay based on QCD factorisation. We
further analyse the CP-conserving observables, , and
. They are practically free of theoretical uncertainties due to
the soft form factors for the full range of dilepton masses rather than just at
a single point as for . They also have a higher sensitivity to specific
new physics scenarios compared to observables such as . Moreover, we
critically examine the new physics reach of CP-violating observables via a
complete error analysis due to scale dependences, form factors and
corrections. We have developed an ensemble method to evaluate the
error on observables from corrections. Finally, we explore the
experimental prospects of CP-violating observables and find that they are
rather limited. Indeed, the CP-conserving (averaged) observables
(with ) will offer a better sensitivity to large CP phases and may be
more suitable for experimental analysis.Comment: 38 pages, 17 figures, updated version to fix a few typo
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