Discovering transiting exoplanets with relatively long orbital periods (\(>\)10 days) is crucial to facilitate the study of cool exoplanet atmospheres (\(T_{\rm eq} < 700 K\)) and to understand ...exoplanet formation and inward migration further out than typical transiting exoplanets. In order to discover these longer period transiting exoplanets, long-term photometric and radial velocity campaigns are required. We report the discovery of TOI-2447 b (\(=\) NGTS-29b), a Saturn-mass transiting exoplanet orbiting a bright (T=10.0) Solar-type star (T\(_{\rm eff}\)=5730 K). TOI-2447 b was identified as a transiting exoplanet candidate from a single transit event of 1.3% depth and 7.29 h duration in \(TESS\) Sector 31 and a prior transit event from 2017 in NGTS data. Four further transit events were observed with NGTS photometry which revealed an orbital period of P=69.34 days. The transit events establish a radius for TOI-2447 b of \(0.865 \pm 0.010\rm R_{\rm J}\), while radial velocity measurements give a mass of \(0.386 \pm 0.025 \rm M_{\rm J}\). The equilibrium temperature of the planet is \(414\) K, making it much cooler than the majority of \(TESS\) planet discoveries. We also detect a transit signal in NGTS data not caused by TOI-2447 b, along with transit timing variations and evidence for a \(\sim\)150 day signal in radial velocity measurements. It is likely that the system hosts additional planets, but further photometry and radial velocity campaigns will be needed to determine their parameters with confidence. TOI-2447 b/NGTS-29b joins a small but growing population of cool giants that will provide crucial insights into giant planet composition and formation mechanisms.
Search for the decay B + → K s 0 K s 0 π Aubert, B.; Lees, J. P.; Prudent, X. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
3/2009, Letnik:
79, Številka:
5
Journal Article
We search for charmless decays of charged B mesons to the three-body final state K_S^0 K_S^0 pi+. Using a data sample of 423.7 fb^-1 collected at the Upsilon(4S) resonance with the BABAR detector, ...corresponding to (465.1 +- 5.1)X10^6 BB-bar pairs, we find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1X10^-7.
The results of Spartan 1 X-ray observations of the region within 1.25 deg of the Galactic center are presented. Four strong, hard X-ray point sources were detected: A1742-294, 1E 1740.7-2942, IE ...1743.1-2843, and a new source SP 1744.2-2959 about 0.5 deg southeast of A1742-294. The new source had an intensity about 20 percent of that of A1742-294 and was relatively hard, having spectral parameters close to those of the diffuse source and of the Galactic bulge source GX 3+1. The Galactic nucleus X-ray source appears to have been a factor of four fainter during the 1985 Spartan 1 observations than during the 1979 Einstein observations. Hard, diffuse X-ray emission centered near the Galactic center, about 1 deg in extent, aligned to within 20 deg of the Galactic equator, and having a maximum 2-10 keV brightness of 1.5 x 10 to the -6th ergs/sq cm/s/sr was detected, as were two weaker point sources about 0.1 deg northeast and southeast of the Galactic nucleus, embedded in the diffuse emission.
Dalitz plot analysis of the decay B0(¯¯¯B0)→K±π∓π0 Zghiche, A.; Pappagallo, M.; Sun, L. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2008, Letnik:
78, Številka:
5
Journal Article
Odprti dostop
We report a Dalitz-plot analysis of the charmless hadronic decays of neutral B mesons to K ± π ∓ π 0 . With a sample of ( 231.8 ± 2.6 ) × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays collected by the BABAR ...detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for B 0 and ¯¯¯ B 0 decays and determine the corresponding C P -averaged branching fractions and charge asymmetries. The inclusive branching fraction and C P -violating charge asymmetry are measured to be B ( B 0 → K + π − π 0 ) = ( 35.7 + 2.6 − 1.5 ± 2.2 ) × 10 − 6 and A C P = − 0.030 + 0.045 − 0.051 ± 0.055 where the first errors are statistical and the second systematic. We observe the decay B 0 → K * 0 ( 892 ) π 0 with the branching fraction B ( B 0 → K * 0 ( 892 ) π 0 ) = ( 3.6 + 0.7 − 0.8 ± 0.4 ) × 10 − 6 . This measurement differs from zero by 5.6 standard deviations (including the systematic uncertainties). The selected sample also contains B 0 → ¯¯¯ D 0 π 0 decays where ¯¯¯ D 0 → K + π − , and we measure B ( B 0 → ¯¯¯ D 0 π 0 ) = ( 2.93 ± 0.17 ± 0.18 ) × 10 − 4 .
Study of the decay D s + → K + K − e + ν e Lees, J. P.; Prudent, X.; Lopez, L. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
09/2008, Letnik:
78, Številka:
5
Journal Article
Odprti dostop
Using 214 fb − 1 of data recorded by the BABAR detector at the PEPII electron-positron collider, we study the decay D + s → K + K − e + ν e . Except for a small S-wave contribution, the events ...with K + K − masses in the range 1.01 - 1.03 GeV / c 2 correspond to ϕ mesons. For D + s → ϕ e + ν e decays, we measure the relative normalization of the Lorentz invariant form factors at q 2 = 0 , r V = V ( 0 ) / A 1 ( 0 ) = 1.849 ± 0.060 ± 0.095 , r 2 = A 2 ( 0 ) / A 1 ( 0 ) = 0.763 ± 0.071 ± 0.065 and the pole mass of the axial-vector form factors m A = ( 2.28 + 0.23 − 0.18 ± 0.18 ) GeV / c 2 . Within the same K + K − mass range, we also measure the relative branching fraction B ( D + s → K + K − e + ν e ) / B ( D + s → K + K − π + ) = 0.558 ± 0.007 ± 0.016 , from which we obtain the total branching fraction B ( D + s → ϕ e + ν e ) = ( 2.61 ± 0.03 ± 0.08 ± 0.15 ) × 10 − 2 . By comparing this value with the predicted decay rate, we extract A 1 ( 0 ) = 0.607 ± 0.011 ± 0.019 ± 0.018 . The stated uncertainties are statistical, systematic, and from external inputs.
Observation of e + e − → ρ + ρ − near s = 10.58 GeV Aubert, B.; Lees, J. P.; Prudent, X. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
10/2008, Letnik:
78, Številka:
7
Journal Article
Odprti dostop
We report the first observation of e + e − → ρ + ρ − , in a data sample of 379 fb − 1 collected with the BABAR detector at the PEP-II e + e − storage ring at center-of-mass energies near √ s = ...10.58 GeV . We measure a cross section of σ ( e + e − → ρ + ρ − ) = 8.3 ± 0.7 ( stat ) ± 0.8 ( syst ) fb within the range of | cos θ ∗ | < 0.8 and | cos θ ± | < 0.85 , where θ ∗ is the center-of-mass polar angle of the ρ ± meson and θ ± are the angles in the ρ ± rest frame between the direction of the boost from the laboratory frame and the direction of the π ± . Assuming production through single-photon annihilation, there are three independent helicity amplitudes. We measure the ratios of their squared moduli to be | F 00 | 2 ∶ | F 10 | 2 ∶ | F 11 | 2 = 0.51 ± 0.14 ( stat ) ± 0.07 ( syst ) ∶ 0.10 ± 0.04 ( stat ) ± 0.01 ( syst ) ∶ 0.04 ± 0.03 ( stat ) ± 0.01 ( syst ) . The | F 00 | 2 result is inconsistent with the prediction of 1.0 made by QCD models with a significance of 3.1 standard deviations including systematic uncertainties.
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