Grand Accélérateur National d'Ions Lourds

We study initial-state radiation events, e+ e- --> gammaISR pi+ pi- J/psi, with data collected with the BABAR detector. We observe an accumulation of events near 4.26 GeV/c2 in the invariant-mass spectrum of pi+ pi- J/psi. Fits to the mass spectrum indicate that a broad resonance with a mass of about 4.26 GeV/c2 is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to 90 MeV/c2, depending on the fit hypothesis.

We study the decay B- --> J/psi K- pi+ pi- using 117 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+ e- asymmetric-energy storage ring. We measure the branching fractions Br(B- --> J/psi K- pi+ pi-) = (116 +- 7 (stat.) +- 9(syst.))* 10-5 and Br(B- --> X(3872)K-)* Br (X(3872) --> J/psi pi+ pi-) =(1.28+- 0.41)* 10-5 and find the mass of the X(3872) to be 3873.4 +- 1.4 MeV/c2. We search for the h_c narrow state in the decay B- --> h_c K-, h_c --> J/psi pi+ pi- and for the decay B- --> J/psi D0 pi-, with D0 --> K- pi+. We set the 90% C.L. limits Br(B- --> h_c K-)* Br (h_c --> J/psi pi+ pi-) <3.4 * 10-6 and Br(B- --> J/psi D0 pi-) <5.2 * 10-5.

The energies of the excited states in very neutron-rich $^{42}\mathrm{S}\mathrm{i}$ and $^{41,43}\mathrm{P}$ have been measured using in-beam $\ensuremath{\gamma}$-ray spectroscopy from the fragmentation of secondary beams of $^{42,44}\mathrm{S}$ at $39A\text{ }\text{ }\mathrm{MeV}$. The low ${2}^{+}$ energy of $^{42}\mathrm{S}\mathrm{i}$, 770(19) keV, together with the level schemes of $^{41,43}\mathrm{P}$, provides evidence for the disappearance of the $Z=14$ and $N=28$ spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that $^{42}\mathrm{S}\mathrm{i}$ is best described as a well-deformed oblate rotor.

This work presents the first continuum shell-model study of weakly bound neutron-rich nuclei involving multiconfiguration mixing. For the single-particle basis, the complex-energy Berggren ensemble representing the bound single-particle states, narrow resonances, and the nonresonant continuum background is taken. Our shell-model Hamiltonian consists of a one-body finite potential and a zero-range residual two-body interaction. It is demonstrated that the residual interaction coupling to the particle continuum is important; in some cases, it can give rise to the binding of a nucleus.

In an experiment at the SISSI-LISE3 facility of GANIL, the decay of the proton drip line nucleus $^{\mathrm{45}}\mathrm{F}\mathrm{e}$ has been studied. Fragment-implantation events have been correlated with radioactive decay events in a $16\ifmmode\times\else\texttimes\fi{}16$ pixel silicon-strip detector. The decay-energy spectrum of $^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implants shows a distinct peak at $(1.14\ifmmode\pm\else\textpm\fi{}0.04)\text{ }\text{ }\mathrm{M}\mathrm{e}\mathrm{V}$ with a half-life of ${T}_{1/2}=({4.7}_{\ensuremath{-}1.4}^{+3.4})\text{ }\text{ }\mathrm{m}\mathrm{s}$. None of the events in this peak is in coincidence with $\ensuremath{\beta}$ particles. For a longer correlation interval, daughter decays of the two-proton daughter $^{\mathrm{43}}\mathrm{C}\mathrm{r}$ can be observed after $^{\mathrm{45}}\mathrm{F}\mathrm{e}$ implantation. The decay energy for $^{\mathrm{45}}\mathrm{F}\mathrm{e}$ agrees nicely with several theoretical predictions for two-proton radioactivity.

We present results on time-dependent $CP$ asymmetries in neutral $B$ decays to several $CP$ eigenstates. The measurements use a data sample of about $88\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected between 1999 and 2002 with the BABAR detector at the PEP-II asymmetric-energy $B$ factory at SLAC. We study events in which one neutral $B$ meson is fully reconstructed in a final state containing a charmonium meson and the other $B$ meson is determined to be either a ${B}^{0}$ or ${\overline{B}}^{0}$ from its decay products. The amplitude of the $CP$ asymmetry, which in the standard model is proportional to $\mathrm{sin}2\ensuremath{\beta}$, is derived from the decay-time distributions in such events. We measure $\mathrm{sin}2\ensuremath{\beta}=0.741\ifmmode\pm\else\textpm\fi{}0.067\mathrm{(}\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{)}\ifmmode\pm\else\textpm\fi{}0.034\mathrm{(}\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{)}$ and $|\ensuremath{\lambda}|=0.948\ifmmode\pm\else\textpm\fi{}0.051\mathrm{(}\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t}\mathrm{)}\ifmmode\pm\else\textpm\fi{}0.030\mathrm{(}\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t}\mathrm{)}$. The magnitude of $\ensuremath{\lambda}$ is consistent with unity, in agreement with the standard model expectation of no direct $CP$ violation in these modes.

This work reviews foundations and applications of the complex-energy continuum shell model that provides a consistent many-body description of bound states, resonances, and scattering states. The model can be considered a quasi-stationary open quantum system extension of the standard configuration interaction approach for well-bound (closed) systems.

The neutron-rich ${}^{66,68}\mathrm{Ni}$ have been produced at GANIL via interactions of a $65.9A\mathrm{MeV}$ ${}^{70}\mathrm{Zn}$ beam with a ${}^{58}\mathrm{Ni}$ target. Their reduced transition probability $B({E2;0}_{1}^{+}\ensuremath{\rightarrow}{2}^{+})$ has been measured for the first time by Coulomb excitation in a ${}^{208}\mathrm{Pb}$ target at intermediate energy. The $B(E2)$ value for ${}^{68}{\mathrm{Ni}}_{40}$ is unexpectedly small. An analysis in terms of large scale shell model calculations stresses the importance of proton core excitations to reproduce the $B(E2)$ values and indicates the erosion of the $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40$ harmonic-oscillator subshell by neutron-pair scattering.

Directed and elliptic flows of neutrons and light-charged particles were measured for the reaction $^{197}\mathrm{Au}+^{197}\mathrm{Au}$ at 400 MeV/nucleon incident energy within the ASY-EOS experimental campaign at the GSI laboratory. The detection system consisted of the Large Area Neutron Detector (LAND), combined with parts of the CHIMERA multidetector, the ALADIN Time-of-flight Wall, and the Washington University Microball detector. The latter three arrays were used for the event characterization and reaction-plane reconstruction. In addition, an array of triple telescopes, KRATTA was used for complementary measurements of the isotopic composition and flows of light-charged particles. From the comparison of the elliptic-flow ratio of neutrons with respect to charged particles with UrQMD predictions, a value $\ensuremath{\gamma}=0.72\ifmmode\pm\else\textpm\fi{}0.19$ is obtained for the power-law coefficient describing the density dependence of the potential part in the parametrization of the symmetry energy. It represents a new and more stringent constraint for the regime of suprasaturation density and confirms, with a considerably smaller uncertainty, the moderately soft to linear density dependence deduced from the earlier FOPI-LAND data. The densities probed are shown to reach beyond twice saturation.

Absolute cross sections for isotopically identified products formed in multinucleon transfer in the (136)Xe+(198)Pt system at ∼8 MeV/nucleon are reported. The isotopic distributions obtained using a large acceptance spectrometer demonstrated the production of the "hard-to-reach" neutron-rich isotopes for Z<78 around the N=126 shell closure far from stability. The main contribution to the formation of these exotic nuclei is shown to arise in collisions with a small kinetic energy dissipation. The present experimental finding corroborates for the first time recent predictions that multinucleon transfer reactions would be the optimum method to populate and characterize neutron-rich isotopes around N=126 which are crucial for understanding both astrophysically relevant processes and the evolution of "magic" numbers far from stability.

The root-mean-square (rms) nuclear charge radius of 8He, the most neutron-rich of all particle-stable nuclei, has been determined for the first time to be 1.93(3) fm. In addition, the rms charge radius of 6He was measured to be 2.068(11) fm, in excellent agreement with a previous result. The significant reduction in charge radius from 6He to 8He is an indication of the change in the correlations of the excess neutrons and is consistent with the 8He neutron halo structure. The experiment was based on laser spectroscopy of individual helium atoms cooled and confined in a magneto-optical trap. Charge radii were extracted from the measured isotope shifts with the help of precision atomic theory calculations.

The ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}p\overline{p}$ cross section is determined over a range of $p\overline{p}$ masses, from threshold to $4.5\text{ }\text{ }\mathrm{GeV}/{c}^{2}$, by studying the ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}p\overline{p}\ensuremath{\gamma}$ process. The data set corresponds to an integrated luminosity of $232\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$, collected with the BABAR detector at the PEP-II storage ring, at an ${e}^{+}{e}^{\ensuremath{-}}$ center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, $|{G}_{E}/{G}_{M}|$, is measured for $p\overline{p}$ masses below $3\text{ }\text{ }\mathrm{GeV}/{c}^{2}$; its value is found to be significantly larger than 1 for masses up to $2.2\text{ }\text{ }\mathrm{GeV}/{c}^{2}$. We also measure $J/\ensuremath{\psi}\ensuremath{\rightarrow}p\overline{p}$ and $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}p\overline{p}$ branching fractions and set an upper limit on $Y(4260)\ensuremath{\rightarrow}p\overline{p}$ production and decay.

The R2E project at CERN has tested a few commercial SRAMs and a custom-designed SRAM, whose data are complementary to various scientific publications. The experimental data include low- and high-energy protons, heavy ions, thermal, intermediate- and high-energy neutrons, high-energy electrons and high-energy pions.

We report results of a study of the ${B}_{s}^{0}$ oscillation frequency using a large sample of ${B}_{s}^{0}$ semileptonic decays corresponding to approximately $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider in 2002--2006. The amplitude method gives a lower limit on the ${B}_{s}^{0}$ oscillation frequency at $14.8\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$ at the 95% C.L. At $\ensuremath{\Delta}{m}_{s}=19\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$, the amplitude deviates from the hypothesis $\mathcal{A}=0$ (1) by 2.5 (1.6) standard deviations, corresponding to a two-sided C.L. of 1% (10%). A likelihood scan over the oscillation frequency, $\ensuremath{\Delta}{m}_{s}$, gives a most probable value of $19\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$ and a range of $17&lt;\ensuremath{\Delta}{m}_{s}&lt;21\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$ at the 90% C.L., assuming Gaussian uncertainties. This is the first direct two-sided bound measured by a single experiment. If $\ensuremath{\Delta}{m}_{s}$ lies above $22\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$, then the probability that it would produce a likelihood minimum similar to the one observed in the interval $16--22\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$ is $(5.0\ifmmode\pm\else\textpm\fi{}0.3)%$.

The coordinating role of nuclear factor erythroid-2-related factor 2 (Nrf2) in cellular function is undeniable. Evidence indicates that this transcription factor exerts massive regulatory functions in multiple signaling pathways concerning redox homeostasis and xenobiotics, macromolecules, and iron metabolism. Being the master regulator of antioxidant system, Nrf2 controls cellular fate, influencing cell proliferation, differentiation, apoptosis, resistance to therapy, and senescence processes, as well as infection disease success. Because Nrf2 is the key coordinator of cell defence mechanisms, dysregulation of its signaling has been associated with carcinogenic phenomena and infectious and age-related diseases. Deregulation of this cytoprotective system may also interfere with immune response. Oxidative burst, one of the main microbicidal mechanisms, could be impaired during the initial phagocytosis of pathogens, which could lead to the successful establishment of infection and promote susceptibility to infectious diseases. There is still a knowledge gap to fill regarding the molecular mechanisms by which Nrf2 orchestrates such complex networks involving multiple pathways. This review describes the role of Nrf2 in non-pathogenic and pathogenic cells.

In-beam $\ensuremath{\gamma}$-ray spectroscopy using fragmentation reactions of both stable and radioactive beams has been performed in order to study the structure of excited states in neutron-rich oxygen isotopes with masses ranging from $A=20$ to 24. For the produced fragments, $\ensuremath{\gamma}$-ray energies, intensities, and $\ensuremath{\gamma}\text{\ensuremath{-}}\ensuremath{\gamma}$ coincidences have been measured. Based on this information new level schemes are proposed for $^{21,22}\mathrm{O}$ up to the neutron separation energy. The nonobservation of any $\ensuremath{\gamma}$-decay branch from $^{23}\mathrm{O}$ and $^{24}\mathrm{O}$ suggests that their excited states lie above the neutron decay thresholds. From this, as well as from the level schemes proposed for $^{21}\mathrm{O}$ and $^{22}\mathrm{O}$, the size of the $N=14$ and 16 shell gaps in oxygen isotopes is discussed in the light of shell-model calculations.

New isomeric states in the neutron-rich nuclei near the $Z\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28$ and $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}40$ shell closures have been identified among the reaction products of a $60.3A$ MeV ${}^{86}\mathrm{Kr}$ beam on a ${}^{\mathrm{nat}}\mathrm{Ni}$ target. From the measured isomeric decay properties information about the excited states and their nuclear structure has been obtained. The isomerism is related mostly to the occupation of the neutron ${g}_{9/2}$ orbital, an intruder level in the $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}3$ $\mathrm{fp}$ shell. It is illustrated with the decay properties of ${}^{69}{\mathrm{Ni}}^{m}$, ${}^{70}{\mathrm{Ni}}^{m}$, and ${}^{71}{\mathrm{Cu}}^{m}$ interpreted within the nuclear shell model.

The masses of 31 neutron-rich nuclei in the range $A\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}29--47$ have been measured. The precision of 19 masses has been significantly improved and 12 masses were measured for the first time. The neutron-rich Cl, S, and P isotopes are seen to exhibit a change in shell structure around $N\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}28$. Comparison with shell model and relativistic mean field calculations demonstrate that the observed effects arise from deformed prolate ground state configurations associated with shape coexistence. Evidence for shape coexistence is provided by the observation of an isomer in ${}^{43}\mathrm{S}$.

We report on a technique that simultaneously quantifies the contact stiffness and dissipation of an AFM cantilever in contact with a surface, which can ultimately be used for quantitative nanomechanical characterization of surfaces. The method is based on measuring the contact resonance frequency using dual AC resonance tracking (DART), where the amplitude and phase of the cantilever response are monitored at two frequencies on either side of the contact resonance. By modelling the tip-sample contact as a driven damped harmonic oscillator, the four measured quantities (two amplitudes and two phases) allow the four model parameters, namely, drive amplitude, drive phase, resonance frequency and quality factor, to be calculated. These mechanical parameters can in turn be used to make quantitative statements about localized sample properties. We apply the method to study the electromechanical coupling coefficients in ferroelectric materials and the storage and loss moduli in viscoelastic materials.

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