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2,673
result(s) for
"Pook, T."
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Genomic prediction using information across years with epistatic models and dimension reduction via haplotype blocks
by
Vojgani, Elaheh
,
Mayer, Manfred
,
Simianer, Henner
in
Accuracy
,
Analysis
,
Biology and Life Sciences
2023
The importance of accurate genomic prediction of phenotypes in plant breeding is undeniable, as higher prediction accuracy can increase selection responses. In this regard, epistasis models have shown to be capable of increasing the prediction accuracy while their high computational load is challenging. In this study, we investigated the predictive ability obtained in additive and epistasis models when utilizing haplotype blocks versus pruned sets of SNPs by including phenotypic information from the last growing season. This was done by considering a single biological trait in two growing seasons (2017 and 2018) as separate traits in a multi-trait model. Thus, bivariate variants of the Genomic Best Linear Unbiased Prediction (GBLUP) as an additive model, Epistatic Random Regression BLUP (ERRBLUP) and selective Epistatic Random Regression BLUP (sERRBLUP) as epistasis models were compared with respect to their prediction accuracies for the second year. The prediction accuracies of bivariate GBLUP, ERRBLUP and sERRBLUP were assessed with eight phenotypic traits for 471/402 doubled haploid lines in the European maize landrace Kemater Landmais Gelb/Petkuser Ferdinand Rot. The results indicate that the obtained prediction accuracies are similar when utilizing a pruned set of SNPs or haplotype blocks, while utilizing haplotype blocks reduces the computational load significantly compared to the pruned sets of SNPs. The number of interactions considered in the model was reduced from 323.5/456.4 million for the pruned SNP panel to 4.4/5.5 million in the haplotype block dataset for Kemater and Petkuser landraces, respectively. Since the computational load scales linearly with the number of parameters in the model, this leads to a reduction in computational time of 98.9% from 13.5 hours for the pruned set of markers to 9 minutes for the haplotype block dataset. We further investigated the impact of genomic correlation, phenotypic correlation and trait heritability as factors affecting the bivariate models’ prediction accuracy, identifying the genomic correlation between years as the most influential one. As computational load is substantially reduced, while the accuracy of genomic prediction is unchanged, the here proposed framework to use haplotype blocks in sERRBLUP provided a solution for the practical implementation of sERRBLUP in real breeding programs. Furthermore, our results indicate that sERRBLUP is not only suitable for prediction across different locations, but also for the prediction across growing seasons.
Journal Article
Search for heavy Higgs bosons decaying to a top quark pair in proton-proton collisions at s = 13 TeV
2020
A
bstract
A search is presented for additional scalar (H) or pseudoscalar (A) Higgs bosons decaying to a top quark pair in proton-proton collisions at a center-of-mass energy of 13 TeV. The data set analyzed corresponds to an integrated luminosity of 35.9 fb
−
1
collected by the CMS experiment at the LHC. Final states with one or two charged leptons are considered. The invariant mass of the reconstructed top quark pair system and variables that are sensitive to the spin of the particles decaying into the top quark pair are used to search for signatures of the H or A bosons. The interference with the standard model top quark pair background is taken into account. A moderate signal-like deviation compatible with an A boson with a mass of 400 GeV is observed with a global significance of 1.9 standard deviations. New stringent constraints are reported on the strength of the coupling of the hypothetical bosons to the top quark, with the mass of the bosons ranging from 400 to 750 GeV and their total relative width from 0.5 to 25%. The results of the search are also interpreted in a minimal supersymmetric standard model scenario. Values of
m
A
from 400 to 700 GeV are probed, and a region with values of tan
β
below 1.0 to 1.5, depending on
m
A
, is excluded at 95% confidence level.
Journal Article
Searches for invisible decays of the Higgs boson in pp collisions at s = 7, 8, and 13 TeV
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Physics
2017
A
bstract
Searches for invisible decays of the Higgs boson are presented. The data collected with the CMS detector at the LHC correspond to integrated luminosities of 5.1, 19.7, and 2.3 fb
−1
at centre-of-mass energies of 7, 8, and 13 TeV, respectively. The search channels target Higgs boson production via gluon fusion, vector boson fusion, and in association with a vector boson. Upper limits are placed on the branching fraction of the Higgs boson decay to invisible particles, as a function of the assumed production cross sections. The combination of all channels, assuming standard model production, yields an observed (expected) upper limit on the invisible branching fraction of 0.24 (0.23) at the 95% confidence level. The results are also interpreted in the context of Higgs-portal dark matter models.
Journal Article
Search for a light pseudoscalar Higgs boson in the boosted μμττ final state in proton-proton collisions at s = 13 TeV
by
Huang, T.
,
Oskin, A.
,
Mishra, T.
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Physics
2020
A
bstract
A search for a light pseudoscalar Higgs boson (a) decaying from the 125 GeV (or a heavier) scalar Higgs boson (H) is performed using the 2016 LHC proton-proton collision data at
s
= 13 TeV, corresponding to an integrated luminosity of 35
.
9 fb
−
1
, collected by the CMS experiment. The analysis considers gluon fusion and vector boson fusion production of the H, followed by the decay H
→
aa
→ μμττ
, and considers pseudoscalar masses in the range 3
.
6
< m
a
<
21 GeV. Because of the large mass difference between the H and the a bosons and the small masses of the a boson decay products, both the
μμ
and the
ττ
pairs have high Lorentz boost and are collimated. The
ττ
reconstruction efficiency is increased by modifying the standard technique for hadronic
τ
lepton decay reconstruction to account for a nearby muon. No significant signal is observed. Model-independent limits are set at 95% confidence level, as a function of
m
a
, on the branching fraction (ℬ) for H
→
aa
→ μμττ
, down to 1
.
5 (2
.
0)
×
10
−
4
for
m
H
= 125 (300) GeV. Model-dependent limits on ℬ(H
→
aa) are set within the context of two Higgs doublets plus singlet models, with the most stringent results obtained for Type-III models. These results extend current LHC searches for heavier a bosons that decay to resolved lepton pairs and provide the first such bounds for an H boson with a mass above 125 GeV.
Journal Article
Search for light bosons in decays of the 125 GeV Higgs boson in proton-proton collisions at s=8 TeV
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Physics
2017
A
bstract
A search is presented for decays beyond the standard model of the 125 GeV Higgs bosons to a pair of light bosons, based on models with extended scalar sectors. Light boson masses between 5 and 62.5 GeV are probed in final states containing four
τ
leptons, two muons and two b quarks, or two muons and two
τ
leptons. The results are from data in proton-proton collisions corresponding to an integrated luminosity of 19.7 fb
−1
, accumulated by the CMS experiment at the LHC at a center-of-mass energy of 8 TeV. No evidence for such exotic decays is found in the data. Upper limits are set on the product of the cross section and branching fraction for several signal processes. The results are also compared to predictions of two-Higgs-doublet models, including those with an additional scalar singlet.
Journal Article
Observation of Y(1S) pair production in proton-proton collisions at s=8 TeV
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Physics
2017
A
bstract
Pair production of Y(1S) mesons is observed at the LHC in proton-proton collisions at
s
=
8
TeV by the CMS experiment in a data sample corresponding to an integrated luminosity of 20.7 fb
−1
. Both Y(1S) candidates are fully reconstructed via their decays to
μ
+
μ
−
. The fiducial acceptance region is defined by an absolute Y(1S) rapidity smaller than 2.0. The fiducial cross section for the production of Y(1S) pairs, assuming that both mesons decay isotropically, is measured to be 68.8±12.7 (stat)±7.4 (syst)±2.8 (
ℬ
) pb, where the third uncertainty comes from the uncertainty in the branching fraction of Y(1S) decays to
μ
+
μ
−
. Assuming instead that the Y(1S) mesons are produced with different polarizations leads to variations in the measured cross section in the range from −38% to +36%.
Journal Article
Measurement of the differential cross section and charge asymmetry for inclusive pp→W±+X production at s=8 TeV
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2016
The differential cross section and charge asymmetry for inclusive
p
p
→
W
±
+
X
→
μ
±
ν
+
X
production at
s
=
8
TeV
are measured as a function of muon pseudorapidity. The data sample corresponds to an integrated luminosity of 18.8
fb
-
1
recorded with the CMS detector at the LHC. These results provide important constraints on the parton distribution functions of the proton in the range of the Bjorken scaling variable
x
from
10
-
3
to
10
-
1
.
Journal Article
Suppression and azimuthal anisotropy of prompt and nonprompt J/ψ production in PbPb collisions at sNN=2.76TeV
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2017
The nuclear modification factor
R
AA
and the azimuthal anisotropy coefficient
v
2
of prompt and nonprompt (i.e. those from decays of b hadrons)
J
/
ψ
mesons, measured from PbPb and pp collisions at
s
NN
=
2.76
TeV
at the LHC, are reported. The results are presented in several event centrality intervals and several kinematic regions, for transverse momenta
p
T
>
6.5
GeV
/
c
and rapidity
|
y
|
<
2.4
, extending down to
p
T
=
3
GeV
/
c
in the
1.6
<
|
y
|
<
2.4
range. The
v
2
of prompt
J
/
ψ
is found to be nonzero, but with no strong dependence on centrality, rapidity, or
p
T
over the full kinematic range studied. The measured
v
2
of nonprompt
J
/
ψ
is consistent with zero. The
R
AA
of prompt
J
/
ψ
exhibits a suppression that increases from peripheral to central collisions but does not vary strongly as a function of either
y
or
p
T
in the fiducial range. The nonprompt
J
/
ψ
R
AA
shows a suppression which becomes stronger as rapidity or
p
T
increases. The
v
2
and
R
AA
of open and hidden charm, and of open charm and beauty, are compared.
Journal Article
Measurement of double-differential cross sections for top quark pair production in pp collisions at s=8TeV and impact on parton distribution functions
by
Thapa, K.
,
Huang, T.
,
Peiffer, T.
in
Astronomy
,
Astrophysics and Cosmology
,
Elementary Particles
2017
Normalized double-differential cross sections for top quark pair (
t
t
¯
) production are measured in pp collisions at a centre-of-mass energy of 8
TeV
with the CMS experiment at the LHC. The analyzed data correspond to an integrated luminosity of 19.7
fb
-
1
. The measurement is performed in the dilepton
e
±
μ
∓
final state. The
t
t
¯
cross section is determined as a function of various pairs of observables characterizing the kinematics of the top quark and
t
t
¯
system. The data are compared to calculations using perturbative quantum chromodynamics at next-to-leading and approximate next-to-next-to-leading orders. They are also compared to predictions of Monte Carlo event generators that complement fixed-order computations with parton showers, hadronization, and multiple-parton interactions. Overall agreement is observed with the predictions, which is improved when the latest global sets of proton parton distribution functions are used. The inclusion of the measured
t
t
¯
cross sections in a fit of parametrized parton distribution functions is shown to have significant impact on the gluon distribution.
Journal Article
Search for a charged Higgs boson in pp collisions at s=8 TeV
by
Pearson, T.
,
Peiffer, T.
,
Hugon, J.
in
Classical and Quantum Gravitation
,
Elementary Particles
,
Hadron-Hadron Scattering
2015
A
bstract
A search for a charged Higgs boson is performed with a data sample corresponding to an integrated luminosity of 19.7 ± 0.5 fb
−1
collected with the CMS detector in proton-proton collisions at
s
=
8
,TeV. The charged Higgs boson is searched for in top quark decays for
m
H
± <
m
t
−
m
b
, and in the direct production pp → t(b)H
±
for
m
H
± >
m
t
−
m
b
. The H
±
→
τ
±
ν
τ
and H
±
→ tb decay modes in the final states
τ
h
+jets,
μτ
h
,
ℓ
+jets, and
ℓℓ
’ (
ℓ
=e,
μ
) are considered in the search. No signal is observed and 95% confidence level upper limits are set on the charged Higgs boson production. A model-independent upper limit on the product branching fraction
ℬ
t
→
H
±
b
ℬ
H
±
→
τ
±
ν
τ
=
1.2
−
0.15
%
is obtained in the mass range
m
H
± = 80–160 GeV, while the upper limit on the cross section times branching fraction
σ
pp
→
t
b
H
±
ℬ
H
±
→
τ
±
ν
τ
=
0.38
−
0.025
pb is set in the mass range
m
H
+ = 180–600 GeV. Here,
σ
(pp → t(b)H
±
) stands for the cross section sum
σ
pp
→
t
¯
b
H
+
+
σ
pp
→
t
b
¯
H
−
. Assuming
ℬ
H
±
→
t
b
=
1
, an upper limit on
σ
(pp → t(b)H
±
) of 2.0–0.13 pb is set for
m
H
± = 180–600 GeV. The combination of all considered decay modes and final states is used to set exclusion limits in the
m
H
±−tan
β
parameter space in different MSSM benchmark scenarios.
Journal Article