A
bstract
The well-known problem of the unknown power corrections within QCD improved factorisation leaves the interpretation of the so-called LHCb anomalies in the angular observables of
B
→
K
∗
μ
+
...μ
−
as an open problem. In order to contribute to the question whether they represent a first sign for new physics beyond the Standard Model or a consequence of underestimated hadronic power corrections, we present a direct comparison of two global fits to the data based on the two different assumptions. In addition, we summarise the possible options to resolve this puzzle in the future.
Likelihood analysis of the minimal AMSB model Bagnaschi, E.; Borsato, M.; Sakurai, K. ...
The European physical journal. C, Particles and fields,
04/2017, Letnik:
77, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We perform a likelihood analysis of the minimal anomaly-mediated supersymmetry-breaking (mAMSB) model using constraints from cosmology and accelerator experiments. We find that either a wino-like or ...a Higgsino-like neutralino LSP,
χ
~
1
0
, may provide the cold dark matter (DM), both with similar likelihoods. The upper limit on the DM density from Planck and other experiments enforces
m
χ
~
1
0
≲
3
TeV
after the inclusion of Sommerfeld enhancement in its annihilations. If most of the cold DM density is provided by the
χ
~
1
0
, the measured value of the Higgs mass favours a limited range of
tan
β
∼
5
(and also for
tan
β
∼
45
if
μ
>
0
) but the scalar mass
m
0
is poorly constrained. In the wino-LSP case,
m
3
/
2
is constrained to about
900
TeV
and
m
χ
~
1
0
to
2.9
±
0.1
TeV
, whereas in the Higgsino-LSP case
m
3
/
2
has just a lower limit
≳
650
TeV
(
≳
480
TeV
) and
m
χ
~
1
0
is constrained to
1.12
(
1.13
)
±
0.02
TeV
in the
μ
>
0
(
μ
<
0
) scenario. In neither case can the anomalous magnetic moment of the muon,
(
g
-
2
)
μ
, be improved significantly relative to its Standard Model (SM) value, nor do flavour measurements constrain the model significantly, and there are poor prospects for discovering supersymmetric particles at the LHC, though there are some prospects for direct DM detection. On the other hand, if the
χ
~
1
0
contributes only a fraction of the cold DM density, future LHC
-based searches for gluinos, squarks and heavier chargino and neutralino states as well as disappearing track searches in the wino-like LSP region will be relevant, and interference effects enable
BR
(
B
s
,
d
→
μ
+
μ
-
)
to agree with the data better than in the SM in the case of wino-like DM with
μ
>
0
.
A
bstract
This report details the capabilities of LHCb and its upgrades towards the study of kaons and hyperons. The analyses performed so far are reviewed, elaborating on the prospects for some key ...decay channels, while proposing some new measurements in LHCb to expand its strangeness research program.
Likelihood analysis of supersymmetric SU(5) GUTs Bagnaschi, E.; Costa, J. C.; Sakurai, K. ...
The European physical journal. C, Particles and fields,
2017/2, Letnik:
77, Številka:
2
Journal Article
Recenzirano
Odprti dostop
We perform a likelihood analysis of the constraints from accelerator experiments and astrophysical observations on supersymmetric (SUSY) models with SU(5) boundary conditions on soft SUSY-breaking ...parameters at the GUT scale. The parameter space of the models studied has seven parameters: a universal gaugino mass
m
1
/
2
, distinct masses for the scalar partners of matter fermions in five- and ten-dimensional representations of SU(5),
m
5
and
m
10
, and for the
5
and
5
¯
Higgs representations
m
H
u
and
m
H
d
, a universal trilinear soft SUSY-breaking parameter
A
0
, and the ratio of Higgs vevs
tan
β
. In addition to previous constraints from direct sparticle searches, low-energy and flavour observables, we incorporate constraints based on preliminary results from 13 TeV LHC searches for jets +
events and long-lived particles, as well as the latest PandaX-II and LUX searches for direct Dark Matter detection. In addition to previously identified mechanisms for bringing the supersymmetric relic density into the range allowed by cosmology, we identify a novel
u
~
R
/
c
~
R
-
χ
~
1
0
coannihilation mechanism that appears in the supersymmetric SU(5) GUT model and discuss the role of
ν
~
τ
coannihilation. We find complementarity between the prospects for direct Dark Matter detection and SUSY searches at the LHC.
The Large Hadron Collider beauty (LHCb) experiment at CERN is undergoing an upgrade in preparation for the Run 3 data collection period at the Large Hadron Collider (LHC). As part of this upgrade, ...the trigger is moving to a full software implementation operating at the LHC bunch crossing rate. We present an evaluation of a CPU-based and a GPU-based implementation of the first stage of the high-level trigger. After a detailed comparison, both options are found to be viable. This document summarizes the performance and implementation details of these options, the outcome of which has led to the choice of the GPU-based implementation as the baseline.
The LHCb measurements on the B ->$ K^*$$\mu^+ \mu^-\( angular observables have shown slight deviations from their Standard Model predictions. The significance of the deviations in the B -> ...\)K^*$$\mu^+ \mu^-$ decay depends on the assumptions on the size of the non-factorisable power corrections. At present, there are no theoretical predictions on the size of these power corrections in order to identify whether the reason behind these anomalies is due to unknown hadronic corrections or New Physics effects. We have performed a statistical comparison of fitting the data to each of the possible explanations.
The well-known problem of the unknown power corrections within QCD improved factorisation leaves the interpretation of the so-called LHCb anomalies in the angular observables of B-->K* mu+ mu- as an ...open problem. In order to contribute to the question whether they represent a first sign for new physics beyond the Standard Model or a consequence of underestimated hadronic power corrections, we present a direct comparison of two global fits to the data based on the two different assumptions. In addition, we summarise the possible options to resolve this puzzle in the future.
We present here a set of examples, classes and tools which can be used for statistical analysis in Graphics Processing Units (GPU). This includes binned and unbinned maximum likelihood fits, ...pseudo-experiment generation, convolutions, Markov Chain Monte Carlo method implementations, and limit setting techniques.
We present the recent measurements of the B0 -> eta' K0 and the B -> omega K decay modes based on the full data set of 772x10^6 BBbar pairs collected by the Belle detector at the KEKB e+e- collider. ...In the B0 -> eta' K^{0} mode, we obtain the CP-violating parameters A(eta'K0) = +0.03+/-0.05(stat)+/-0.04(syst), S(eta'K0) = +0.68+/-0.07(stat)+/-0.03(syst). This is the world's most precise result on the eta' K0 CP parameters. In B -> omega K decays, we measure the branching fractions B(B0 -> omega K0) = (4.5+/-0.4(stat)+/-0.3(syst))x10^-6, B(B- -> omega K-) = (6.8+/-0.4(stat)+/-0.4(syst))x10^-6, which are their current most precise results. We measure the first evidence of CP violation in the B0 -> omega K0S decay mode, obtaining the CP-violating parameters A(omega K0S} = -0.36+/-0.19(stat)+/-0.05(syst), S(omega K0S} = +0.91+/-0.32(stat)+/-0.05(syst). In the B- -> omega K- mode, we measure the direct CP-violation parameter A(omega K-) = -0.03+/-0.04(stat)+/-0.01(syst), which is its most precise measurement to date.
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