Measurement of Subthreshold K+ Production in pA Collisions with ANKE

title: Measurement of the pn ---> dK+ K- total cross section close to threshold
abstract: Measurements of the pd → p sp dK + K - reaction, where p sp is a spectator proton, have been undertaken at the Cooler Synchrotron COSY-Jiilich by detecting a fast deuteron in coincidence with a K + K - pair in the ANKE facility. Although the proton beam energy was fixed, the moving target neutron allowed values of the nonresonant quasifree pn → dK + K - total cross section to be deduced up to an excess energy e ≈ 100 MeV. Evidence is found for the effects of K - d and KK final state interactions. The comparison of these data with those of pp → ppK + K - and pp → dK + K 0 shows that all the total cross sections are very similar in magnitude.

title: Differential cross section and analysing power of the quasi-free pn ->{pp}_s pi- reaction at 353 MeV
abstract: In order to establish links between p-wave pion production in nucleon-nucleon collisions and low energy three-nucleon scattering, an extensive programme of experiments on pion production is currently underway at COSY-ANKE. The final proton pair is measured at very low excitation energy, leading to an S-wave diproton, denoted here as {pp}s. By using a deuterium target we have obtained data on the differential cross section and analysing power of the quasi-free ~ pn → {pp}sπ − reaction at 353 MeV. The spectator proton psp was either measured directly in silicon tracking telescopes or reconstructed using the momentum of a detected π −. Both observables can be described in terms of s-, p-, and d-wave pion production amplitudes. Taken together with the analogous data on the ~pp → {pp}s π 0 reaction, full partial wave decompositions of both processes were carried out.

title: Investigation of the reaction pp->p K0 pi+ Lambda in search of the pentaquark
abstract: The reaction pp->p K0 pi+ Lambda has been studied with the ANKE spectrometer at COSY-Juelich at a beam momentum of 3.65 GeV/c in order to search for a possible signal of the pentaquark Theta+(1540), decaying into the p K0 system. By detecting four charged particles in the final state, the K0 and the Lambda have been reconstructed to tag strangeness production. It has been found that the pi+ Lambda missing-mass spectrum displays no significant signal expected from the Theta+(1540) excitation. The total cross section for the reaction pp->p K0 pi+ Lambda has been deduced, as well as an upper limit for the Theta+ production cross section. The intermediate Delta++ K0 Lambda state is found to provide a significant contribution to the reaction.

title: Neutron-proton charge-exchange amplitudes at 585 MeV
abstract: The differential cross section and deuteron analysing powers of the d → p → {pp}n charge–exchange reaction have been measured with the ANKE spectrometer at the COSY storage ring. Using a deuteron beam of energy 1170 MeV, data were obtained for small momentum transfers to a {pp} system with low excitation energy. A good quantitative understanding of all the measured observables is provided by the impulse approximation using known neutron–proton amplitudes. The proof of principle achieved here for the method suggests that measurements at higher energies will provide useful information in regions where the existing np database is far less reliable. PACS. 13.75.-n Hadron-induced lowand intermediate-energy reactions and scattering (energy ≤ 1GeV) – 25.45.De Deuteron breakup – 25.45.Kk Charge–exchange reactions

title: Measurement of the in-medium phi-meson width in proton-nucleus collisions
abstract: The production of φ mesons in the collisions of 2.83 GeV protons with C, Cu, Ag, and Au at forward angles has been measured via the φ → KK decay using the COSY-ANKE magnetic spectrometer. The φ meson production cross section follows a target mass dependence of A in the momentum region of 0.6–1.6 GeV/c. The comparison of the data with model calculations suggests that the in-medium φ width is about an order of magnitude larger than its free value.

title: DETERMINATION OF THE INCLINATION OF THE MULTI-PLANET HOSTING STAR HR 8799 USING ASTEROSEISMOLOGY*
abstract: Direct imaging of the HR 8799 system was a major achievement in the study of exoplanets. HR 8799 is a {gamma} Doradus variable and asteroseismology can provide an independent constraint on the inclination. Using 650 high signal-to-noise, high-resolution, full visual wavelength spectroscopic observations obtained over two weeks at Observatoire de Haute Provence with the SOPHIE spectrograph, we find that the main frequency in the radial velocity data is 1.9875 day{sup -1}. This frequency corresponds to the main frequency as found in previous photometric observations. Using the FAMIAS software to identify the pulsation modes, we find that this frequency is a prograde l = 1 sectoral mode and obtain the constraint that inclination i {approx}> 40{sup 0}.

title: Oscillations in Procyon A First results from a multi-site campaign
abstract: Procyon A is a bright F5IV star in a binary system. Although the distance, mass and angular diameter of this star are all known with high precision, the exact evolutionary state is still unclear. Evolutionary tracks with different ages and different mass fractions of hydrogen in the core pass, within the errors, through the observed position of Procyon A in the Hertzsprung-Russell diagram. For more than15 years several different groups have studied the solar-like oscillations in Procyon A to determine its evolutionary state. Although several studies independently detected power excess in the periodogram, there is no agreement on the actual oscillation frequencies yet. This is probably due to either insufficient high-quality data (i.e., aliasing) or due to intrinsic properties of the star (i.e., short mode lifetimes). Now a spectroscopic multi-site campaign using 10 telescopes world-wide (minimizing aliasing effects) with a total time span of nearly 4 weeks (increase the frequency resolution) is performed to identify frequencies in this star and finally determine its properties and evolutionary state.

title: 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
abstract: 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.

title: HD 181068: A Red Giant in a Triply Eclipsing Compact Hierarchical Triple System
abstract: The Kepler satellite reveals details of the oscillations patterns of an evolved star in an exotic triple-star system. Hierarchical triple systems comprise a close binary and a more distant component. They are important for testing theories of star formation and of stellar evolution in the presence of nearby companions. We obtained 218 days of Kepler photometry of HD 181068 (magnitude of 7.1), supplemented by ground-based spectroscopy and interferometry, which show it to be a hierarchical triple with two types of mutual eclipses. The primary is a red giant that is in a 45-day orbit with a pair of red dwarfs in a close 0.9-day orbit. The red giant shows evidence for tidally induced oscillations that are driven by the orbital motion of the close pair. HD 181068 is an ideal target for studies of dynamical evolution and testing tidal friction theories in hierarchical triple systems.