Search for evidence of (3)(Lambda)n by observing d + pi(-) and t + pi(-) final states in the reaction of Li-6+C-12 at 2A GeV

<p>The experimental data obtained from the reaction of Li-6 projectiles at 2A GeV on a fixed graphite target were analyzed to study the invariant mass distributions of d + pi(-) and t + pi(-). Indications of a signal in the d + pi(-) and t + pi(-) invariant mass distributions were observed with significances of 5.3 sigma and 5.0 sigma, respectively, when including the production target, and 3.7 sigma and 5.2 sigma, respectively, when excluding the target. The estimated mean values of the invariant mass for d + pi(-) and t + pi(-) signal were 2059.3 +/- 1.3 +/- 1.7 MeV/c(2) and 2993.7 +/- 1.3 +/- 0.6 MeV/c(2) respectively. The lifetime estimation of the possible bound states yielding to d + pi(-) and t + pi(-) final states were deduced to be as 181(-24)(+30) +/- 25 ps and 190(-35)(+47) +/- 36 ps, respectively. Those final states may be interpreted as the two-body and three-body decay modes of a neutral bound state of two neutrons and a Lambda hyperon, (3)(Lambda)n.</p>

Hypernuclear spectroscopy of products from Li-6 projectiles on a carbon target at 2 A GeV

<p>A novel experiment, aiming at demonstrating the feasibility of hypernuclear spectroscopy with heavy ion beams, was conducted. Using the invariant mass method, the spectroscopy of hypernuclear products of Li-6 projectiles on a carbon target at 2 A GeV was performed. Signals of the Lambda-hyperon and H-3(Lambda) and H-4(Lambda) hypernuclei were observed for final states of p + pi(-), He-3 + pi(-) and He-4 + pi(-), respectively, with significance values of 6.7, 4.7 and 4.9 sigma. By analyzing the proper decay time from secondary vertex distribution with the unbinned maximum likelihood fitting method, their lifetime values were deduced to be 262(-43)(+56) +/- 45 ps for Lambda, 183(-32)(+42) +/- 37 ps for H-3(Lambda), and 140(-33)(+48) +/- 35 ps for H-4(Lambda). (c) 2013 Elsevier B.V. All rights reserved.</p>

VizieR Online Data Catalog: 3C 279 Event Horizon Telescope imaging (Kim+, 2020)

We release a data set to accompany the "First 3C279 Event Horizon Telescope Results" paper (Kim et al. 2020). The data set is derived from the Science Release 1 (SR1) of the Event Horizon Telescope (EHT)'s April 2017 observation campaign (EHTC et al. 2019ApJ...875L...3E). This data set contains 3C279 data for both low and high bands for all observed days (April 5th, 6th, 10th, 11th, 2017). Data from the 2017 observations were processed through three independent reduction pipelines (Blackburn et al., 2019ApJ...882...23B, Janssen et al., 2019A&A...626A..75J, EHTC et al. 2019ApJ...875L...3E). This release includes the fringe fitted, a-priori calibrated, and network calibrated data from the EHT-HOPS pipeline, which is the primary data set for the First 3C279 EHT results. Independent flux calibration is performed based on estimated station sensitivities during the campaign (Issaoun et al., 2017, EHT Memo 2017-CE-02, Janssen et al. 2019A&A...626A..75J,). A description of the data properties, their validation, and estimated systematic errors is given in EHTC et al. (2019ApJ...875L...3E) with additional details in Wielgus et al. (2019, https://eventhorizontelescope.org/for-astronomers/memos). The data are time averaged to 10 seconds and frequency averaged over all 32 intermediate frequencies (IFs). All polarization information is explicitly removed. To make the resulting 'uvfits' files compatible with popular very-long-baseline interferometry (VLBI) software packages, the circularly polarized cross-hand visibilities 'RL' and 'LR' are set to zero along with their errors, while parallel-hands 'RR' and 'LL' are both set to an estimated Stokes I value. Measurement errors for 'RR' and 'LL' are each set to sqrt(2) times the statistical errors for Stokes I. All uvfits files are located in the "uvfits/" subdirectory. Easy-to-read csv and txt files are derived from the uvfits files and provided in "csv" and "txt", respectively. Scripts that generate these files from the original SR1 data are also included. Finally, the run.sh script in the top directory will convert uvfits files into csv and txt files. The three tgz files are gzipped tarballs that contains uvfits, txt, and csv files, respectively. They are included in this repository for convenience. (10 data files)