Tind Technologies (Norway)

IUScholarWorks Open

Not a member yet

2995 research outputs found

Sort by

A Bayesian General Linear Modeling Approach to Cortical Surface fMRI Data Analysis

Author: Mejia Amanda Farrier
Yue Yu Ryan
Bolin David
Lindgren Finn
Lindquist Martin
Publication venue
Publication date: 2020
Field of study

Cortical surface functional magnetic resonance imaging (cs-fMRI) has recently grown in popularity versus traditional volumetric fMRI. In addition to offering better whole-brain visualization, dimension reduction, removal of extraneous tissue types, and improved alignment of cortical areas across subjects, it is also more compatible with common assumptions of Bayesian spatial models. However, as no spatial Bayesian model has been proposed for cs-fMRI data, most analyses continue to employ the classical general linear model (GLM), a “massive univariate” approach. Here, we propose a spatial Bayesian GLM for cs-fMRI, which employs a class of sophisticated spatial processes to model latent activation fields. We make several advances compared with existing spatial Bayesian models for volumetric fMRI. First, we use integrated nested Laplacian approximations, a highly accurate and efficient Bayesian computation technique, rather than variational Bayes. To identify regions of activation, we utilize an excursions set method based on the joint posterior distribution of the latent fields, rather than the marginal distribution at each location. Finally, we propose the first multi-subject spatial Bayesian modeling approach, which addresses a major gap in the existing literature. The methods are very computationally advantageous and are validated through simulation studies and two task fMRI studies from the Human Connectome Project. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement

Evidence for the decays of $\Lambda^+_{c}\to\Sigma^+\eta$ and $\Sigma^+\eta^\prime$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

We study the hadronic decays of

\Lambda^+_{c}

to the final states

\Sigma^+\eta

and

\Sigma^+\eta^\prime

, using an

e^+e^-

annihilation data sample of 567 pb

^{-1}

taken at a center-of-mass energy of 4.6 GeV with the BESIII detector at the BEPCII collider. We find evidence for the decays

\Lambda^+_{c}\to\Sigma^+\eta

and

\Sigma^+\eta^\prime

with statistical significance of 2.5

\sigma

and 3.2

\sigma

, respectively. Normalizing to the reference decays

\Lambda_c^+\to\Sigma^+\pi^0

and

\Sigma^+\omega

, we obtain the ratios of the branching fractions

\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\pi^0)}

and

\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\omega)}

to be 0.35±0.16±0.03 and 0.86±0.34±0.07, respectively. The upper limits at the 90\% confidence level are set to be

\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\pi^0)}<0.58

and

\frac{{\mathcal B}(\Lambda_c^+\to\Sigma^+\eta^\prime)}{{\mathcal B}(\Lambda_c^+\to\Sigma^+\omega)}<1.2

. Using BESIII measurements of the branching fractions of the reference decays, we determine

\mathcal B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta})=(0.41\pm0.19\pm0.05)\% (<0.68\%)

and

\mathcal B({\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta'})=(1.34\pm0.53\pm0.21)\%

(<1.9%). Here, the first uncertainties are statistical and the second systematic. The obtained branching fraction of

\Lambda_c^+\to\Sigma^+\eta

is consistent with the previous measurement, and the branching fraction of

\Lambda_{c}^{+}\rightarrow\Sigma^{+}\eta^{\prime}

is measured for the first time

Improved measurements of the absolute branching fractions of the inclusive decays $D^{+(0)}\to\phi X$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

By analyzing 2.93 fb

^{−1}

e^+e^−

annihilation data taken at the center-of-mass energy

\sqrt s

= 3.773 GeV with the BESIII detector, we determine the branching fractions of the inclusive decays

D^+\to\phi X

and

D^0\to\phi X

to be (1.135 ± 0.034 ± 0.031)% and (1.091 ± 0.027 ± 0.035)% , respectively, where

X

denotes any possible particle combination. The first uncertainties are statistical, and the second are systematic. We also determine the branching fractions of the decays

D\to\phi X

and their charge conjugate modes

\bar{D}\to\phi \bar{X}

separately for the first time, and no significant CP asymmetry is observed

Observation of $\psi(3686) \to p \bar{p} \eta^{\prime}$ and improved measurement of $J/\psi \to p \bar{p} \eta^{\prime}$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

We observe the process

\psi(3686) \to p \bar{p} \eta^{\prime}

for the first time, with a statistical significance higher than 10

\sigma

, and measure the branching fraction of

J/\psi \to p \bar{p} \eta^{\prime}

with an improved accuracy compared to earlier studies. The measurements are based on

4.48×10^8

\psi(3686)

and

1.31×10^9

J/\psi

events collected by the BESIII detector operating at the BEPCII. The branching fractions are determined to be

B(\psi(3686) \to p \bar{p} \eta^{\prime}) = (1.10\pm0.10\pm0.08)\times10^{-5}

and

B(J/\psi \to p \bar{p} \eta^{\prime})=(1.26\pm0.02\pm 0.07)\times10^{-4}

, where the first uncertainties are statistical and the second ones systematic. Additionally, the

\eta-\eta^{\prime}

mixing angle is determined to be

-24^{\circ} \pm 11^{\circ}

based on

\psi(3686) \to p \bar{p} \eta^{\prime}

, and

-24^{\circ} \pm 9^{\circ}

based on

J/\psi \to p \bar{p} \eta^{\prime}

, respectively

Observation of $D^+_s\rightarrow p\bar{n}$ and confirmation of its large branching fraction

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

The baryonic decay

D^+_s\rightarrow p\bar{n}

is observed, and the corresponding branching fraction is measured to be (1.21±0.10±0.05)×10

^{−3}

, where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII

e^+e^−

double-ring collider with a center-of-mass energy of 4.178 GeV and an integrated luminosity of 3.19fb

^{−1}

. The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision, which may deepen our understanding of the dynamical enhancement of the

W

-annihilation topology in the charmed meson decays

Observation of the $W$ -Annihilation Decay $D^{+}_{s} \rightarrow \omega \pi^{+}$ and Evidence for $D^{+}_{s} \rightarrow \omega K^{+}$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

We report on the observation of the

W

-annihilation decay

D^{+}_{s} \rightarrow \omega \pi^{+}

and the evidence for

D_{s}^{+} \rightarrow \omega K^{+}

with a data sample corresponding to an integrated luminosity of 3.19 fb

^{−1}

collected with the BESIII detector at the center-of-mass energy

\sqrt{s}

= 4.178 GeV. We obtain the branching fractions

\mathcal{B}(D^{+}_{s} \rightarrow \omega \pi^{+}) = (1.77\pm0.32_{\rm stat.}\pm0.11_{\rm sys.}) \times 10^{-3}

and

\mathcal{B}(D^{+}_{s} \rightarrow \omega K^{+}) = (0.87\pm0.24_{\rm stat.}\pm0.07_{\rm sys.}) \times 10^{-3}

, respectively

Partial-wave analysis of $J/\psi\to K^+K^-\pi^0$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

A partial-wave analysis of the decay

J/\psi \to K^+K^-\pi^0

has been made using

(223.7±1.4)×10^6

J/\psi

events collected with the BESIII detector in 2009. The analysis, which is performed within the isobar-model approach, reveals contributions from

K^*_2(1430)^\pm

K^*_2(1980)^\pm

and

K^*_4(2045)^\pm

decaying to

K^\pm\pi^0

. The two latter states are observed in

J/\psi

decays for the first time. Two resonance signals decaying to

K^+K^−

are also observed. These contributions can not be reliably identified and their possible interpretations are discussed. The measured branching fraction

B(J/\psi \to K^+K^-\pi^0)

(2.88±0.01±0.12)×10^{−3}

is more precise than previous results. Branching fractions for the reported contributions are presented as well. The results of the partial-wave analysis differ significantly from those previously obtained by BESII and BABAR

Study of electromagnetic Dalitz decays $\chi_{cJ} \rightarrow \mu^{+}\mu^{-}J/\psi$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

Using

4.48×10^8

\psi(3686)

events collected with the BESIII detector, we search for the decays

\chi_{cJ} \rightarrow \mu^{+}\mu^{-}J/\psi

through the radiative decays

\psi(3686) \rightarrow \gamma\chi_{cJ}

, where

J=0,1,2

. The decays

\chi_{c1,2} \rightarrow \mu^{+}\mu^{-}J/\psi

are observed, and the corresponding branching fractions are measured to be

\mathcal{B}(\chi_{c1} \rightarrow \mu^{+}\mu^{-}J/\psi) = (2.51 \pm 0.18 \pm 0.20)\times10^{-4}

and

\mathcal{B}(\chi_{c2} \rightarrow \mu^{+}\mu^{-}J/\psi) = (2.33 \pm 0.18 \pm 0.29)\times10^{-4}

, where the first uncertainty is statistical and the second one systematic. No significant

\chi_{c0} \rightarrow \mu^{+}\mu^{-}J/\psi

decay is observed, and the upper limit on the branching fraction is determined to be

2.0×10^{−5}

at 90% confidence level. Also, we present a study of di-muon invariant mass dependent transition form factor for the decays

\chi_{c1,2} \rightarrow \mu^{+}\mu^{-}J/\psi

Study of the Dalitz decay $J/\psi \to e^+e^- \eta$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

We study the electromagnetic Dalitz decay

J/\psi \to e^+e^- \eta

and search for di-electron decays of a dark gauge boson

(\gamma')

J/\psi \to \gamma' \eta

with the two

\eta

decay modes

\eta \rightarrow \gamma \gamma

and

\eta \rightarrow \pi^+\pi^-\pi^0

using

(1310.6±7.0)×10^6

J/\psi

events collected with the BESIII detector. The branching fraction of

J/\psi \to e^+e^- \eta

is measured to be

(1.43 \pm 0.04 ({\rm stat}) \pm 0.06 ({\rm syst}))\times 10^{-5}

, with a precision that is improved by a factor of 1.5 over the previous BESIII measurement. The corresponding di-electron invariant mass dependent modulus square of the transition form factor is explored for the first time, and the pole mass is determined to be

\Lambda = 2.84 \pm 0.11({\rm stat}) \pm 0.08({\rm syst})

GeV/

c^2

. We find no evidence of

\gamma'

production and set 90% confidence level upper limits on the product branching fraction

\mathcal{B}(J/\psi \to \gamma' \eta)\times \mathcal{B}(\gamma' \to e^+e^-)

as well as the kinetic mixing strength between the Standard Model photon and

\gamma'

in the mass range of

0.01 \le m_{\gamma'} \le 2.4

GeV/

c^2

Study of the Decays $D_{s}^{+} \rightarrow K_{S}^{0}K^{+}$ and $K_{L}^{0}K^{+}$

Author: Ablikim M.
Mitchell R. E., et al.
Publication venue
Publication date: 2020
Field of study

Using an

e^+e^−

annihilation data sample corresponding to an integrated luminosity of 3.19 fb

^{−1}

and collected at a center-of-mass energy

\sqrt{s}

= 4.178 GeV with the BESIII detector, we measure the absolute branching fractions

\mathcal{B}(D_{s}^{+} \rightarrow K_{S}^{0}K^{+}) = (1.425\pm0.038_{\rm stat.}\pm0.031_{\rm syst.})\%

and

\mathcal{B}(D_{s}^{+} \rightarrow K_{L}^{0}K^{+}) =(1.485\pm0.039_{\rm stat.}\pm0.046_{\rm syst.})\%

. The branching fraction of

D_{s}^{+} \rightarrow K_{S}^{0}K^{+}

is compatible with the world average and that of

D_{s}^{+} \rightarrow K_{L}^{0}K^{+}

is measured for the first time. We present the first measurement of the

K_{S}^{0}-K_{L}^{0}

asymmetry in the decays

D_{s}^{+} \rightarrow K_{S,L}^{0}K^{+}

, and

R(D_{s}^{+} \rightarrow K_{S,L}^{0}K^{+})=\frac{\mathcal{B}(D_{s}^{+} \rightarrow K_{S}^{0}K^{+}) -\mathcal{B}(D_{s}^{+} \rightarrow K_{L}^{0}K^{+})}{\mathcal{B}(D_{s}^{+} \rightarrow K_{S}^{0}K^{+}) +\mathcal{B}(D_{s}^{+} \rightarrow K_{L}^{0}K^{+})}= (-2.1\pm1.9_{\rm stat.}\pm1.6_{\rm syst.})\%

. In addition, we measure the direct

CP

asymmetries

A_{\rm CP}(D_{s}^{\pm} \rightarrow K_{S}^{0}K^{\pm}) = (0.6\pm2.8_{\rm stat.}\pm0.6_{\rm syst.})\%

and

A_{\rm CP}(D_{s}^{\pm} \rightarrow K_{L}^{0}K^{\pm}) = (-1.1\pm2.6_{\rm stat.}\pm0.6_{\rm syst.})\%

685

full texts

2,995

metadata records

Updated in last 30 days.

IUScholarWorks Open

Access Repository Dashboard

Do you manage Open Research Online? Become a CORE Member to access insider analytics, issue reports and manage access to outputs from your repository in the CORE Repository Dashboard! 👇