33873040
Near-threshold production of phi mesons in pp collisions.
The pp-->ppphi reaction has been studied at the Cooler Synchrotron COSY-Jülich, using the internal beam and ANKE facility. Total cross sections have been determined at three excess energies epsilon near the production threshold. The differential cross section closest to threshold at epsilon=18.5 MeV exhibits a clear S wave dominance as well as a noticeable effect due to the proton-proton final-state interaction. Taken together with data for ppomega production, a significant enhancement of the phi/omega ratio of a factor 8 is found compared to predictions based on the Okubo-Zweig-Iizuka rule.
119445528
Vector and tensor analysing powers in deuteron-proton breakup reactions at intermediate energies
Abstract Vector and tensor analysing powers of the d → p → ( p p ) n (charge-exchange) and d → p → ( p n ) p (non-charge-exchange) breakup reactions have been measured with the ANKE spectrometer at the COSY ring at a deuteron beam energy of 1170 MeV for small momentum transfers to the low excitation energy ( p p ) or ( p n ) systems. A quantitative understanding of the values of A x x and A y y for the charge-exchange reaction is provided by impulse approximation calculations. The data suggest that spin-flip isospin-flip transitions, which dominate the charge-exchange breakup of the deuteron, are also important in the non-charge-exchange reaction.
118789979
Measurement of Subthreshold K+ Production in pA Collisions with ANKE
56319302
THE FORWARD DETECTOR OF THE ANKE SPECTROMETER. SCINTILLATION AND CHERENKOV HODOSCOPES
Central Institute for Nuclear Research, Rossendorf, GermanyThe scintillation and Cherenkov counter system of the forward detector of ANKE, magnetic spec-trometer at the internal beam of the accelerator COSY in Jeulich, is described. The timing and amplitudecharacteristics are presented as well as the capabilities to select physical processes of interest.¶¨¸O¢ ¥E¸O ¸¨¸E¥³ ¸I¨´E¨²²O I¨µ´´OI ¨ I¥·¥´±µ¢¸±¨I ¸I¥EI¨±µ¢ ¶¥·¥¤´¥£µ ¤¥E¥±Eµ· ANKE, ³ £´¨E´µ£µ ¸¶¥±E·µ³¥E· ´ ¢´EE·¥´´¥³ ¶EI±¥ E¸±µ·¨E¥²O COSY ¢ ²¨I¥. ·¨¢¥¤¥´O¨I ¢·¥³¥´´O¥ ¨ ³¶²¨EE¤´O¥ I · ±E¥·¨¸E¨±¨, E ±¦¥ ¢µ§³µ¦´µ¸E¨ ¨I ¶·¨³¥´¥´¨O ¤²O ¢O¤¥²¥´¨O¨´E¥·¥¸EOÐ¨I E¨§¨I¥¸±¨I ¶·µI¥¸¸µ¢.
7502590
Inclusive K+-meson production in proton-nucleus interactions
Abstract.The production of K+-mesons in pA (A = D, C, Cu, Ag, Au) collisions has been investigated at the COoler SYnchrotron COSY-Jülich for beam energies Tp = 1.0-2.3 GeV. Double differential inclusive pC cross-sections at forward angles ϑ{K^+} < 12° as well as the target mass dependence of the K+ momentum spectra have been measured with the ANKE spectrometer. Far below the free NN threshold at TNN = 1.58 GeV the spectra reveal a high degree of collectivity in the target nucleus. From the target mass dependence of the cross-sections at higher energies, the repulsive in-medium potential of the K+-mesons can be deduced. Using pN cross-section parameterisations from the literature and our measured pD data we derive a cross-section ratio σ(pn↦K+X)/σ(pp↦K+X) ∼ (3-4).
121039239
Identification of K+-mesons from subthreshold pA collisions with ANKE at COSY-Jülich
Abstract The spectrometer ANKE has been put into operation at the accelerator COSY of the Forschungszentrum Julich in spring 1998. An initial scientific goal is to study K + -production in pA collisions at subthreshold energies far below the free NN-threshold at T p =1.58 GeV. This requires the identification of K + -mesons in a background of pions and protons, about 10 6 times more intense. In this paper the sophisticated detection system and the software procedures for kaon identification are described. With the help of TOF, energy-loss and range measurements as well as the track information from wire chambers, it is possible to measure d 2 σ/ d Ω d p for deep subthreshold K + production at beam energies down to T p =1.0 GeV.
55685116
A substellar component orbiting the F-star 30 Arietis B
Context. Most current radial velocity planet search programs have concentrated on stars of one solar mass. Our knowledge on the frequency of giant planets and brown dwarf companions to more massive stars is thus rather limited. In the case of solar-like stars, the frequency of short-period brown dwarf companions and very massive planets seems to be low. Aims. Here we present evidence for a substellar companion to 30 Ari B, an F-star of 1.16 ± 0.04 $M_\odot$ that is a member of a hierarchical triple system. Methods. The companion was detected by means of precise radial velocity measurements using the 2-m Alfred-Jensch telescope and its echelle spectrograph. An iodine absorption cell provided the wavelength reference for precise stellar radial velocity measurements. Results. We analyzed our radial velocity measurements and derived an orbit to the companion with period, P = 335.1 ± 2.5 days, eccentricity e = 0.289 ± 0.092, and mass function $f(m)$ = (6.1 ± 1.7)$\times$10 -7 $M_\odot$. Conclusions. We conclude that the radial velocity variations of 30 Ari B are due to a companion with m  sin  i of 9.88 ± 0.94 $M_{\mathrm{Jup}}$ that is either a massive planet or a brown dwarf. The object thus belongs to the rare class of massive planets and brown dwarfs orbiting main- sequence stars.
14319327
Confirmation of the Planet Hypothesis for the Long-period Radial Velocity Variations of Beta Geminorum
Aims. Our aim is to confirm the nature of the long period radial velocity measurements for β Gem first found by Hatzes & Cochran (1993). Methods. We present precise stellar radial velocity measurements for the K giant star β Gem spanning over 25 years. An examination of the Ca II K emission, spectral line shapes from high resolution data ($R = 210\,000$), and Hipparcos photometry was also made to discern the true nature of the long period radial velocity variations. Results. The radial velocity data show that the long period, low amplitude radial velocity variations found by Hatzes & Cochran (1993) are long-lived and coherent. Furthermore, the Ca II K emission, spectral line bisectors, and Hipparcos photometry show no significant variations of these quantities with the radial velocity period. An orbital solution assuming a stellar mass of 1.7 $M_\odot$ yields a period, $P = 589.6$ days, a minimum mass of 2.3 M Jupiter , and a semi-major axis, $a = 1.6$ AU. The orbit is nearly circular ($e = 0.02$). Conclusions. The data presented here confirm the planetary companion hypothesis suggested by Hatzes & Cochran (1993). β Gem is one of six intermediate mass stars known to host a sub-stellar companion and suggests that planet-formation around stars much more massive than the sun may common.
119184639
Transiting exoplanets from the CoRoT space mission XIV. CoRoT-11b: a transiting massive "hot-Jupiter" in a prograde orbit around a rapidly rotating F-type star
The CoRoT  exoplanet science team announces the discovery of CoRoT-11b, a fairly massive hot-Jupiter transiting a V  = 12.9 mag F6 dwarf star ( M ∗  = 1.27 ± 0.05  M ⊙ , R ∗  = 1.37 ± 0.03  R ⊙ , T eff  = 6440 ± 120 K), with an orbital period of P  = 2.994329 ± 0.000011 days and semi-major axis a  = 0.0436 ± 0.005 AU. The detection of part of the radial velocity anomaly caused by the Rossiter-McLaughlin effect shows that the transit-like events detected by CoRoT  are caused by a planet-sized transiting object in a prograde orbit. The relatively high projected rotational velocity of the star ( v sin i ⋆  = 40 ± 5 km s -1 ) places CoRoT-11 among the most rapidly rotating planet host stars discovered so far. With a planetary mass of M p   = 2.33 ± 0.34  M Jup  and radius R p   = 1.43 ± 0.03  R Jup , the resulting mean density of CoRoT-11b ( ρ p  = 0.99 ± 0.15 g/cm 3 ) can be explained with a model for an inflated hydrogen-planet with a solar composition and a high level of energy dissipation in its interior.
23202373
Planetary transit candidates in the CoRoT LRa01 field
Context. The space mission CoRoT is devoted to the analysis of stellar variability and the photometric detection of extrasolar planets. Aims. We present the list of planetary transit candidates detected in the first short run observed by CoRoT that targeted SRc01, towards the Galactic center in the direction of Aquila, which lasted from April to May 2007. Methods. Among the acquired data, we analyzed those for 1269 sources in the chromatic bands and 5705 in the monochromatic band. Instrumental noise and the stellar variability were treated with several detrending tools, to which several transit-search algorithms were subsequently applied. Results. Fifty-one sources were classified as planetary transit candidates and 26 were followed up with ground-based observations. Until now, no planet has been detected in the CoRoT data from the SRc01 field.