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At least 19 recordsLinked to original sources
arXiv2025

NTIRE 2025 Challenge on Video Quality Enhancement for Video Conferencing: Datasets, Methods and Results

This paper presents a comprehensive review of the 1st Challenge on Video Quality Enhancement for Video Conferencing held at the NTIRE workshop at CVPR 2025, and highlights the problem statement, datasets, proposed solutions, and results. The aim of this challenge was to design a Video Quality Enhancement (VQE) model to enhance video quality in video conferencing scenarios by (a) improving lighting, (b) enhancing colors, (c) reducing noise, and (d) enhancing sharpness - giving a professional studio-like effect. Participants were given a differentiable Video Quality Assessment (VQA) model, training, and test videos. A total of 91 participants registered for the challenge. We received 10 valid submissions that were evaluated in a crowdsourced framework.

cs.CV↗
arXiv2020

NTIRE 2020 Challenge on Spectral Reconstruction from an RGB Image

This paper reviews the second challenge on spectral reconstruction from RGB images, i.e., the recovery of whole-scene hyperspectral (HS) information from a 3-channel RGB image. As in the previous challenge, two tracks were provided: (i) a "Clean" track where HS images are estimated from noise-free RGBs, the RGB images are themselves calculated numerically using the ground-truth HS images and supplied spectral sensitivity functions (ii) a "Real World" track, simulating capture by an uncalibrated and unknown camera, where the HS images are recovered from noisy JPEG-compressed RGB images. A new, larger-than-ever, natural hyperspectral image data set is presented, containing a total of 510 HS images. The Clean and Real World tracks had 103 and 78 registered participants respectively, with 14 teams competing in the final testing phase. A description of the proposed methods, alongside their challenge scores and an extensive evaluation of top performing methods is also provided. They gauge the state-of-the-art in spectral reconstruction from an RGB image.

eess.IV↗
arXiv2019

Computation Resource Leasing for Priority Aggregation Local Computing Network

In large scale smart edge networks, computation resource is generally underutilized due to the uneven distribution of computation resource in time and space domain. This may correspond to a simple fact that no device is capable for 'storing' and 'exchanging' idle computation resource. Thus, this paper proposes a computation resource leasing (CRL) concept using priority as an intermediary to restore and exchange the permission for computation resource for priority aggregation local computing network (PALCN). Each device in PALNC is able to gain priority as a reward for leasing its computing resource to others. CRL also offers a priority oriented algorithm to match the computation request with idle source nodes and a priority management model. Our analysis and numerical results show that the system can efficiently utilize local idle computation sources over time and space domain and filtrate the big task that local computation can not finish.

cs.NI↗
arXiv2018

Observation of the decay $D^0\rightarrow K^-\pi^+e^+e^-$

We report the observation of the rare charm decay $D^0\rightarrow K^-\pi^+e^+e^-$, based on $468$ fb$^{-1}$ of $e^+e^-$ annihilation data collected at or close to the center-of-mass energy of the $Y(4S)$ resonance with the BaBar detector at the SLAC National Accelerator Laboratory. We find the branching fraction in the invariant mass range $0.675< m(e^+e^-) < 0.875 GeV/c^2$ of the electron-positron pair to be ${\cal B}(D^0\rightarrow K^-\pi^+e^+e^-) = (4.0\pm0.5\pm0.2\pm0.1) \times 10^{-6}$, where the first uncertainty is statistical, the second systematic, and the third due to the uncertainty in the branching fraction of the decay $D^0\rightarrow K^-\pi^+\pi^+\pi^-$ used as a normalization mode. The significance of the observation corresponds to 9.7 standard deviations including systematic uncertainties. This result is consistent with the recently reported $D^0\rightarrow K^-\pi^+\mu^+\mu^-$ branching fraction, measured in the same invariant mass range, and with the value expected in the Standard Model. In a set of regions of $m(e^+e^-)$ where long-distance effects are potentially small, we determine a 90% confidence level upper limit on the branching fraction ${\cal B}(D^0\rightarrow K^-\pi^+e^+e^-) < 3.1 \times 10^{-6}$.

hep-ex↗
arXiv2016

Gaia Data Release 1, Pre-processing and source list creation

The first data release from the Gaia mission contains accurate positions and magnitudes for more than a billion sources, and proper motions and parallaxes for the majority of the 2.5~million Hipparcos and Tycho-2 stars. We describe three essential elements of the initial data treatment leading to this catalogue: the image analysis, the construction of a source list, and the near real-time monitoring of the payload health. We also discuss some weak points that set limitations for the attainable precision at the present stage of the mission. Image parameters for point sources are derived from one-dimensional scans, using a maximum likelihood method, under the assumption of a line spread function constant in time, and a complete modelling of bias and background. These conditions are, however, not completely fulfilled. The Gaia source list is built starting from a large ground-based catalogue, but even so a significant number of new entries have been added, and a large number have been removed. The autonomous onboard star image detection will pick up many spurious images, especially around bright sources, and such unwanted detections must be identified. Another key step of the source list creation consists in arranging the more than $10^{10}$ individual detections in spatially isolated groups that can be analysed individually. Complete software systems have been built for the Gaia initial data treatment, that manage approximately 50~million focal plane transits daily, giving transit times and fluxes for 500~million individual CCD images to the astrometric and photometric processing chains. The software also carries out a successful and detailed daily monitoring of Gaia health.

astro-ph.IM↗
arXiv2016

Search for transient gravitational waves in coincidence with short duration radio transients during 2007-2013

We present an archival search for transient gravitational-wave bursts in coincidence with 27 single pulse triggers from Green Bank Telescope pulsar surveys, using the LIGO, Virgo and GEO interferometer network. We also discuss a check for gravitational-wave signals in coincidence with Parkes Fast Radio Bursts using similar methods. Data analyzed in these searches were collected between 2007 and 2013. Possible sources of emission of both short-duration radio signals and transient gravitational-wave emission include starquakes on neutron stars, binary coalescence of neutron stars, and cosmic string cusps. While no evidence for gravitational-wave emission in coincidence with these radio transients was found, the current analysis serves as a prototype for similar future searches using more sensitive second-generation interferometers.

astro-ph.HE↗
arXiv2015

Time-dependent analysis of $B^0 \to {{K^0_{S}}} \pi^- \pi^+ \gamma$ decays and studies of the $K^+\pi^-\pi^+$ system in $B^+ \to K^+ \pi^- \pi^+ \gamma$ decays

We measure the time-dependent $CP$ asymmetry in the radiative-penguin decay $B^0 \to {{K^0_{S}}} \pi^- \pi^+ \gamma$, using a sample of $471$ million $\Upsilon(4S) \to B{\kern 0.18em\overline{\kern -0.18em B}}$ events recorded with the BaBar detector at the PEP-II $e^+e^-$ storage ring at SLAC. Using events with $m_{K\pi\pi}<1.8{\mathrm{\,Ge\kern -0.1em V/}c^2}$, we measure the branching fractions of $B^+ \to K^+ \pi^- \pi^+ \gamma$ and $B^0 \to K^0 \pi^+ \pi^- \gamma$, the branching fractions of the kaonic resonances decaying to $K^+ \pi^- \pi^+$, as well as the overall branching fractions of the $B^+ \to \rho^0 K^+ \gamma$, $B^+ \to K^{*0} \pi^+ \gamma$ and S-wave $B^+ \to (K \pi)^{*0}_0 \pi^+ \gamma$ components. For events from the $\rho$ mass band, we measure the $CP$-violating parameters ${\mathcal{S}_{{{K^0_{S}}}\pi^+\pi^-\gamma}} = 0.14 \pm 0.25 \pm 0.03$ and ${\mathcal{C}_{{{K^0_{S}}}\pi^+\pi^-\gamma}} = -0.39 \pm 0.20^{+0.03}_{-0.02}$, where the first uncertainties are statistical and the second are systematic. We extract from this measurement the time-dependent $CP$ asymmetry related to the $CP$ eigenstate $\rho^0 {{K^0_{S}}}$ and obtain ${\mathcal{S}_{{{K^0_{S}}}\rho\gamma}} = -0.18 \pm 0.32^{+ 0.06}_{-0.05}$, which provides information on the photon polarization in the underlying $b \to s \gamma$ transition.

hep-ex↗
arXiv2015

Measurement of the I=1/2 $K \pi$ $\mathcal{S}$-wave amplitude from Dalitz plot analyses of $\eta_c \to K \bar K \pi$ in two-photon interactions

We study the processes $\gamma \gamma \to K^0_S K^{\pm}\pi^{\mp}$ and $\gamma \gamma \to K^+ K^- \pi^0$ using a data sample of 519~$fb^{-1}$ recorded with the BaBar detector operating at the SLAC PEP-II asymmetric-energy $e^+ e^-$ collider at center-of-mass energies at and near the $\Upsilon(nS)$ ($n = 2,3,4$) resonances. We observe $\eta_c$ decays to both final states and perform Dalitz plot analyses using a model-independent partial wave analysis technique. This allows a model-independent measurement of the mass-dependence of the $I=1/2$ $K \pi$ $\mathcal{S}$-wave amplitude and phase. A comparison between the present measurement and those from previous experiments indicates similar behaviour for the phase up to a mass of 1.5 $GeV/c^2$. In contrast, the amplitudes show very marked differences. The data require the presence of a new $a_0(1950)$ resonance with parameters $m=1931 \pm 14 \pm 22 \ MeV/c^2$ and $\Gamma=271 \pm 22 \pm 29 \ MeV$.

hep-ex↗
arXiv2015

Collins asymmetries in inclusive charged $KK$ and $K\pi$ pairs produced in $e^+e^-$ annihilation

We present measurements of Collins asymmetries in the inclusive process $e^+e^- \rightarrow h_1 h_2 X$, $h_1h_2=KK,\, K\pi,\, \pi\pi$, at the center-of-mass energy of 10.6 GeV, using a data sample of 468 fb$^{-1}$ collected by the BaBar experiment at the PEP-II $B$ factory at SLAC National Accelerator Center. Considering hadrons in opposite thrust hemispheres of hadronic events, we observe clear azimuthal asymmetries in the ratio of unlike- to like-sign, and unlike- to all charged $h_1 h_2$ pairs, which increase with hadron energies. The $K\pi$ asymmetries are similar to those measured for the $\pi\pi$ pairs, whereas those measured for high-energy $KK$ pairs are, in general, larger.

hep-ex↗
arXiv2015

Search for Long-Lived Particles in $e^+e^-$ Collisions

We present a search for a neutral, long-lived particle $L$ that is produced in $e^+e^-$ collisions and decays at a significant distance from the $e^+e^-$ interaction point into various flavor combinations of two oppositely charged tracks. The analysis uses an $e^+e^-$ data sample with a luminosity of $489.1 \rm{fb}^{-1}$ collected by the BaBar detector at the $\Upsilon$(4S), $\Upsilon$(3S), and $\Upsilon$(2S) resonances and just below the $\Upsilon$(4S). Fitting the two-track mass distribution in search of a signal peak, we do not observe a significant signal, and set 90% confidence level upper limits on the product of the $L$ production cross section, branching fraction, and reconstruction efficiency for six possible two-body $L$ decay modes as a function of the $L$ mass. The efficiency is given for each final state as a function of the mass, lifetime, and transverse momentum of the candidate, allowing application of the upper limits to any production model. In addition, upper limits are provided on the branching fraction $Br(B\to X_s L)$, where $X_s$ is a strange hadronic system.

hep-ex↗
arXiv2014

Dalitz plot analyses of $B^0 \to D^- D^0 K^+$ and $B^+ \to \overline{D}^0 D^0 K^+$ decays

We present Dalitz plot analyses for the decays of $B$ mesons to $D^- D^0 K^+$ and $\overline{D}^0 D^0 K^+$. We report the observation of the $D^{*}_{s1}(2700)^+$ resonance in these two channels and obtain measurements of the mass $M(D^{*}_{s1}(2700)^+) = 2699 {}^{+14}_{-7} \, \mathrm{MeV}/c^2$ and of the width $\Gamma(D^{*}_{s1}(2700)^+) = 127 {}^{+24}_{-19} \, \mathrm{MeV}$, including statistical and systematic uncertainties. In addition, we observe an enhancement in the $D^0K^+$ invariant mass around 2350--2500 MeV/$c^2$ in both decays $B^0 \to D^- D^0 K^+$ and $B^+ \to \overline{D}^0 D^0 K^+$, which we are not able to interpret. The results are based on $429~\mathrm{fb}^{-1}$ of data containing $471\times10^6\, B\overline{B}$ pairs collected at the $\Upsilon{(4S)}$ resonance with the BaBar detector at the SLAC National Accelerator Laboratory.

hep-ex↗
arXiv2014

Search for new $\pi^0$-like particles produced in association with a $\tau$-lepton pair

We report on a search in $e^+e^-$ annihilations for new $\pi^0$-like particles produced in association with a $\tau$-lepton pair. These objects, with a similar mass and similar decay modes to $\pi^0$ mesons, could provide an explanation for the non-asymptotic behavior of the pion-photon transition form factor observed by the Babar Collaboration. No significant signal is observed, and limits on the production cross section at the level of 73 fb or 370 fb, depending on the model parameters, are determined at 90% confidence level. These upper limits lie below the cross section values needed to explain the Babar form factor data.

hep-ex↗
arXiv2014

Study of CP asymmetry in B0-B0bar mixing with inclusive dilepton events

We present a measurement of the asymmetry $A_{CP}$ between same-sign inclusive dilepton samples $\ell^+ \ell^+$ and $\ell^- \ell^-$ ($\ell= e, \mu$) from semileptonic B decays in Y(4S) --> BBbar events, using the complete data set recorded by the BABAR experiment near the Y(4S) resonance, corresponding to 471 million BBbar pairs. The asymmetry A_{CP} allows comparison between the mixing probabilities P(B0bar --> B0) and P(B0 --> B0bar), and therefore probes CP and T violation. The result, $A_{CP} = (-3.9 \pm 3.5 (stat) \pm 1.9 (syst)) \times 10^{-3}$, is consistent with the Standard Model expectation.

hep-ex↗
arXiv2014

Verification of Maxwell-Boltzmann distribution with Big-Bang Nucleosyntheis theory

The current Big-Bang Nucleosynthesis (BBN) model has been constructed based on a nuclear reaction network operating with thermal reactivities of Maxwell-Boltzmann (MB) distribution plasma. However, does the classical MB distribution still hold for the extremely high-temperature (in order of 10$^9$ K) plasma involved in the Big-Bang environment? In this work, we have investigated the impact of non-extensive Tsallis statistics (in $q$-Guassian distribution) on the thermonuclear reaction rates. We show for the first time that the reverse rates are extremely sensitive to the non-extensive $q$ parameter. Such sensitivity does not allow a large deviation of non-extensive distribution from the usual MB distribution. With a newly developed BBN code, the impact of primordial light-element abundances on $q$ values has been studied by utilizing the most recent BBN cosmological parameters and the available nuclear cross-section data. For the first time, we have accurately verified the microscopic MB distribution with the macroscopic BBN theory and bservation. By comparing the recent observed primordial abundances with our predictions, only a tiny deviation of $\pm$6$\times$10$^{-4}$ at most can be allowed for the MB distribution. However, validity of the classical statistics needs to be studied further for the self-gravitating stars and binaries of high-density environment, with the extreme sensitivity of reverse rate on $q$ found here.

astro-ph.SR↗
arXiv2014

Evidence for the baryonic decay B0bar --> D0 Lambda Lambdabar

Evidence is presented for the baryonic $B$ meson decay $\bar{B}\rightarrow D^0 \Lambda \bar{\Lambda}$ based on a data sample of $471 \times 10^6$ $B\bar{B}$ pairs collected with the {\it BABAR} detector at the PEP2 asymmetric $e^+e^-$ collider located at the SLAC National Accelerator Laboratory. The branching fraction is determined to be $\mathcal{B}(\bar{B}\rightarrow D^0 \Lambda \bar{\Lambda}) = (9.8^{+2.9}_{-2.6} \pm 1.9)\times 10^{-6}$, corresponding to a significance of $3.4$ standard deviations including systematic uncertainties. A search for the related baryonic $B$ meson decay $\bar{B}\rightarrow D^0 \Sigma^0 \bar{\Lambda}$ with $\Sigma^0\rightarrow\Lambda\gamma$ is performed and an upper limit $\mathcal{B}(\bar{B}\rightarrow D^0 \Sigma^0 \bar{\Lambda} + \bar{B}\rightarrow D^0 \Lambda \bar{\Sigma}^0) < 3.1 \times 10^{-5}$ is determined at $90\%$ confidence level.

hep-ex↗
arXiv2013

Measurement of the B->Xsl+l- branching fraction and search for direct CP violation from a sum of exclusive final states

We present a measurement of the total branching fraction of the flavor-changing neutral-current process B->Xsl+l-, along with partial branching fractions in bins of dilepton and hadronic system (Xs) mass, using a sample of 471x10^6 Upsilon(4S)->BBbar events recorded with the BaBar detector at the PEP-II e+e- collider. B mesons are reconstructed by combining a dilepton pair, either e+e- or mu+mu-, with 10 different Xs final states containing exactly one charged or neutral kaon, two or fewer charged pions, and at most one pi0. Using a sum over these exclusive modes as the basis for extrapolation to the fully inclusive rate, we measure a lepton-flavor-averaged inclusive branching fraction BF(B->Xsl+l-) = (6.73 +0.70-0.64[stat] +0.34-0.25[exp syst] +/- 0.50[model syst])x10^-6 for m(l+l-)^2>0.1 GeV^2/c^4. Restricting our analysis exclusively to final states from which a decaying B meson's flavor can be inferred, we additionally report measurements of the direct CP asymmetry ACP in bins of dilepton mass; over the full dilepton mass range, we find ACP=0.04 +/- 0.11 +/- 0.01$ for a lepton-flavor-averaged sample.

hep-ex↗
arXiv2013

Search for lepton-number violating B+ -> X- l+ l'+ decays

We report on a search for eleven lepton-number violating processes B+ -> X- l+ l'+ with X- = K-, pi-, rho-, K*- or D- and l+/l'+ = e+ or mu+, using a sample of 471+/-3 million BBbar events collected with the BaBar detector at the PEP-II e+e- collider at the SLAC National Accelerator Laboratory. We find no evidence for any of these modes and place 90% confidence level upper limits on their branching fractions in the range $(1.5-26)\times 10^{-7}$.

hep-ex↗