Reconciling the results of the z ~ 2 MOSDEF and KBSS-MOSFIRE Surveys

Large scale structure and cosmolog

Interferon-alpha up-regulates bcl-2 expression and protects B-CLL cells from apoptosis in-vitro and in-vivo

The bcl-2 oncoprotein, which is involved in the t(14,18) translocation, protects cells against apoptosis. We examined the effects of interferon-alpha (IFN-alpha) on bcl-2 protein expression and apoptosis in B-chronic lymphocytic leukaemia (B-CLL) cells. None of 12 patients with B-CLL examined expressed the t(14,18) translocation; however, all these, and seven other patients, expressed significant levels of bcl-2 protein. In vitro, IFN-alpha (500 U/ml over 18 h) increased bcl-2 expression on CLL cells (to 200 +/- 23% of control MCF, as determined by indirect immunofluorescence and flow cytometry, n = 10, P < 0.001). All of eight patients who received IFN-alpha (3 megaunits subcutaneously three times a week) demonstrated an increase in bcl-2 expression on circulating malignant cells. CLL cells undergo apoptotic cell death when cultured in vitro (35.6 +/- 10.3% DNA fragmentation after 18 h, n = 10). In the presence of IFN-alpha, however, DNA fragmentation was reduced to 6.6 +/- 5.8% (n = 10, P < 0.001). IFN-alpha also protected CLL cells against apoptosis induced by hydrocortisone and gamma irradiation (reducing DNA fragmentation from 63.9 +/- 12.6% to 10.8 +/- 4.5% and from 80 +/- 2.9% to 5.4 +/- 1.6%, respectively, P < 0.001 for both). The protective effect of IFN-alpha was dose dependent, and maintained for up to 24 h. Our data demonstrate that bcl-2 expression and apoptosis of CLL cells can be influenced by cytokines. In addition, it seems unlikely that the observed clinical responses to IFN-alpha in patients with CLL are due to a direct effect on the malignant cells

A study of the centrally produced π+π-π0 system formed in the reaction pp→pf(π+π-π0)ps at 300 GeV/c

The reaction pp→pf(π+π-π0)ps, where the π+π-π0 system is centrally produced, has been studied at 300 GeV/c. The π+π-π0 mass spectrum shows evidence for the η, ω and a2 (1320) as well as an enhancement in the a1 (1260) region. A Dalitz plot analysis of the π+π-π0 system has been performed. The a1 (1260) parameters coming from the fit of the 1+S wave are m=1208±15 MeV and Γ=430±50 MeV. No evidence is found for the h1(1170) or h1(1380). © 1990 Springer-Verlag

Study of the centrally producer ππ and K Mathematical expression systems at 85 and 300 GeV/c

We have studied the ππ and K Mathematical expression systems centrally produced in proton proton collisions at 300 GeV/c and π+/p proton collisions at 85 GeV/c using the CERN Ω spectrometer. Clear evidence for S*/fo(975) production is observed. An analysis performed on the π+ π- mass spectrum in the 1.0 GeV region, using a coupled channel formalism, shows that it is possible to describe the S*/fo(975) effect with one single resonance once interference of the S*/fo(975) with the S-wave background is introduced. The resulting S*/fo(975) parameters are mo=979±4MeV, gπ=0.28±0.04, gK=0.56±0.18 corresponding to a pole position on sheet II at (1001±2)-i(36±4) MeV. Evidence is also found for a structure having a mass of 1472±12 MeV and a width of 195±33 MeV. © 1991 Springer-Verlag

A study of the centrally produced K*0 {Mathematical expression} final state in the reaction pp→pf(K+K-π+π-)ps at 300 GeV/c

The reaction pp→pf(K+K-π+π-)ps, where the K+K- π+π- system is centrally produced, has been studied at 300 GeV/c. The K*0 {Mathematical expression} final state has been observed and the cross sections for its central production are found to be the same at 300 and 85 GeV/c. The K*0 {Mathematical expression} final state appears to be produced as a non-resonant threshold enhancement. © 1990 Springer-Verlag

A search for non-qq mesons in the central region

The aim of this experiment is to search for non-qq mesons in the reaction pp→pf(XO)ps at 300 GeV/c incident momentum, where the XO system is a centrally produced meson. The θ/f2(1720), E/f1(1420) and a new state in the 2π+2π- channel are presented as candidate non-qq mesons. © 1990

Study of the centrally produced ππ and KK systems

We have studied the ππ and K K ̄ systems centrally produced in proton collisions at 300 GeV/c. Clear evidence for S*/fhook0(975) production is observed. An analysis performed on the π+π- mass spectrum in the 1.0 GeV region, using a coupled channel formalism, shows that it is possible to describe the S*/fhook0(975) effect with one single resonance, and requires interference of the S*/fhook0(975) with the S-wave background. The resulting S*/fhook0(975) parameters are m0 = 979 ± 4 MeV, gπ = 0.28 ± 0.04, gK = 0.56 ± 0.18. Evidence is found for a structure having a mass of 1472 ± 12 MeV and a width of 195 ± 33 MeV. © 1991

Search for higher twists in meson resonance production in π- N interactions at PT≥2 GeV/c

We study the production of meson resonance at pT≥2 GeV/c in π- Be interactions at two beam energies (150 and 300 GeV/c). The motivation is to look for the higher twist (HT) production mechanism, expected to exist besides standard hadron production through the fragmentation process of scattered quarks and gluons, the so-called leading twist (LT) mechanism. We show that the φ, K*0 (892) and K*0 (892) are found free from HT effects with a good accuracy, as expected from HT estimates and QCD sum rules. The magnitudes of the f2(1270) and ρ0 mesons signals are found larger than expected from the standard Lund (LT) Monte Carlo and from information provided by e+ e- annihilation experiments. The possible connection of these excesses with HT physics is discussed. We also report the first evidence for the production of f0(975) mesons in hadronic experiments at large pT. © 1996 Springer-Verlag

Short-range correlations in hadron pair production at pT≧2 GeV/c

Production of oppositely charged particle pairs at large pT is studied, where both particles, are in the central rapidity region within one unit of rapidity and nearby in azimuth. The data sample, which comes from π- Be interactions obtained using the CERN OMEGA spectrometer, contains events with a pair of oppositely charged particles having pT≧2 GeV/c recoiling, against a third one with pT≧1 GeV/c. Our data provide new information on short range correlations involving the production of the nine possible pairs made from (π+, K+, p) and {Mathematical expression}. Comparison with Lund Monte Carlo predictions is made. Apart from proton yields, the model reproduces correctly our data. The main discrepancies observed with protons can be attributed to hard scattering of diquarks from the target nucleons. © 1992 Springer-Verlag

Shape distortions of meson resonances produced in hadron interactions at PT≧2 GeV/c

We study the shape of the invariant mass spectra of several resonances produced at PT≧2.0 GeV/c and observed through two-particle final states, namely the f2(1270), K*(892), {Mathematical expression}, K*(1430), and {Mathematical expression} mesons. The data sample comes from π- Be interactions at Plab=150 GeV/c and 300 GeV/c which have been collected using the OMEGA spectrometer at CERN. We find that although these meson resonances have their masses and widths consistent with the corresponding world average values, their shapes are all subject to the same kind of distortion: their low-mass tail is enhanced while their high-mass tail is sharply cut. This observation indicates that meson resonances produced in the fragmentation of quarks and gluons are distorted by the same damping factor in a way which preserves their masses and lifetimes. © 1994 Springer-Verlag