Design of a detector to study S=−2$S = - 2$ baryon interactions induced by stopped antiproton annihilation

Stopped antiproton annihilation can initiate an effcient chain of reactions to produce Ξ hyperons in recoil free kinematics, suitable for further investigations of ΞN interactions. Four delayed decays and presence of eight charged particles in the final state provide a clean reaction signature and allow for usage of a non-magnetic detection system. With the low energy phase space cooled antiproton beam from ELENA at the CERN AD or future FLAIR facility the realisation of this experiment would become possible. In this article the foreseen detector setup and the experimental program will be presented.

Polarization analysis of p̄ produced in pA collisions

A quite simple procedure for the generation of a polarized antiproton beam could be worked out if antiprotons are produced with some polarization. In order to investigate this possibility measurements of the polarization of produced antiprotons have been started at a CERN/PS test beam. The polarization will be determined from the asymmetry of the elastic antiproton scattering at a liquid hydrogen target in the CNI region for which the analyzing power is well known. The data are under analysis and an additional measurement is done in 2018. Details on the experiment and the ongoing data analysis will be given.

Drift chamber calibration and particle identification in the P-349 experiment

The goal of the P-349 experiment is to test whether 3.5 GeV/c antiprotons produced in high-energy proton-proton collisions are polarized in view of the preparation of a polarized antiproton beam. In this article, we present the details of the ongoing analysis focused on the drift chambers calibration and particle identification with DIRC.

Lyman-α source for laser cooling antihydrogen

We present a Lyman-α laser developed for cooling trapped antihydrogen. The system is based on a pulsed Ti:sapphire laser operating at 729 nm that is frequency doubled using an LBO crystal and then frequency tripled in a Kr/Ar gas cell. After frequency conversion, this system produces up to 5.7 μW of average power at the Lyman-α wavelength. This laser is part of the ATRAP experiment at the antiproton decelerator in CERN.

Phase Locking the Spin Precession in a Storage Ring

This Letter reports the successful use of feedback from a spin polarization measurement to the revolution frequency of a 0.97  GeV/c bunched and polarized deuteron beam in the Cooler Synchrotron (COSY) storage ring in order to control both the precession rate (≈121  kHz) and the phase of the horizontal polarization component. Real time synchronization with a radio frequency (rf) solenoid made possible the rotation of the polarization out of the horizontal plane, yielding a demonstration of the feedback method to manipulate the polarization. In particular, the rotation rate shows a sinusoidal function of the horizontal polarization phase (relative to the rf solenoid), which was controlled to within a 1 standard deviation range of σ=0.21  rad. The minimum possible adjustment was 3.7 mHz out of a revolution frequency of 753 kHz, which changes the precession rate by 26  mrad/s. Such a capability meets a requirement for the use of storage rings to look for an intrinsic electric dipole moment of charged particles.

How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring

We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10^{-29}  e cm.

New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments

A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by ν(s)=γG (γ is the Lorentz factor, G the gyromagnetic anomaly). At 970  MeV/c, the deuteron spins coherently precess at a frequency of ≈120  kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10^{-8}, and to 1×10^{-10} for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.

Determination of the η(')-proton scattering length in free space

Taking advantage of both the high mass resolution of the COSY-11 detector and the high energy resolution of the low-emittance proton beam of the cooler synchrotron COSY, we determine the excitation function for the pp→ppη(') reaction close to threshold. Combining these data with previous results, we extract the scattering length for the η(')-proton potential in free space to be Re(a(pη(')))=0±0.43  fm and Im(a(pη(')))=0.37(-0.16)(+0.40)  fm.

One-particle measurement of the antiproton magnetic moment

For the first time a single trapped antiproton (p) is used to measure the p magnetic moment μ(p). The moment μ(p)=μ(p)S/(ℏ/2) is given in terms of its spin S and the nuclear magneton (μ(N)) by μ(p)/μ(N)=-2.792 845±0.000 012. The 4.4 parts per million (ppm) uncertainty is 680 times smaller than previously realized. Comparing to the proton moment measured using the same method and trap electrodes gives μ(p)/μ(p)=-1.000 000±0.000 005 to 5 ppm, for a proton moment μ(p)=μ(p)S/(ℏ/2), consistent with the prediction of the CPT theorem.

Trapped antihydrogen in its ground state

Antihydrogen atoms (H¯) are confined in an Ioffe trap for 15-1000 s-long enough to ensure that they reach their ground state. Though reproducibility challenges remain in making large numbers of cold antiprotons (p¯) and positrons (e(+)) interact, 5±1 simultaneously confined ground-state atoms are produced and observed on average, substantially more than previously reported. Increases in the number of simultaneously trapped H¯ are critical if laser cooling of trapped H¯ is to be demonstrated and spectroscopic studies at interesting levels of precision are to be carried out.

Adiabatic cooling of antiprotons

Adiabatic cooling is shown to be a simple and effective method to cool many charged particles in a trap to very low temperatures. Up to 3×10(6) p are cooled to 3.5 K-10(3) times more cold p and a 3 times lower p temperature than previously reported. A second cooling method cools p plasmas via the synchrotron radiation of embedded e(-) (with many fewer e(-) than p in preparation for adiabatic cooling. No p are lost during either process-a significant advantage for rare particles.

Centrifugal separation of antiprotons and electrons

Centrifugal separation of antiprotons and electrons is observed, the first such demonstration with particles that cannot be laser cooled or optically imaged. The spatial separation takes place during the electron cooling of trapped antiprotons, the only method available to produce cryogenic antiprotons for precision tests of fundamental symmetries and for cold antihydrogen studies. The centrifugal separation suggests a new approach for isolating low energy antiprotons and for producing a controlled mixture of antiprotons and electrons.

Determination of the total width of the η' meson

Taking advantage of both the low-emittance proton beam of the cooler synchrotron COSY and the high momentum precision of the COSY-11 detector system, the mass distribution of the η' meson was measured with a resolution of 0.33  MeV/c2 (FWHM), improving the experimental mass resolution by almost an order of magnitude with respect to previous results. Based on the sample of more than 2300 reconstructed pp → ppη' events, the total width of the η' meson was determined to be Γ(η') = 0.226 ± 0.017(stat) ± 0.014(syst)  MeV/c2.

Antihydrogen production within a Penning-Ioffe trap

Slow antihydrogen (H) is produced within a Penning trap that is located within a quadrupole Ioffe trap, the latter intended to ultimately confine extremely cold, ground-state H[over ] atoms. Observed H[over ] atoms in this configuration resolve a debate about whether positrons and antiprotons can be brought together to form atoms within the divergent magnetic fields of a quadrupole Ioffe trap. The number of detected H atoms actually increases when a 400 mK Ioffe trap is turned on.

Mechanism of near-threshold production of the eta meson

Measurements of the analyzing power for the pp-->pp eta reaction have been performed at excess energies of Q=10 and 36 MeV. The determined analyzing power is essentially consistent with zero, implying dominance of the s wave at both excess energies. The angular dependence of the analyzing power, combined with the isospin dependence of the total cross section for the eta meson production in nucleon-nucleon collisions, reveal that the excitation of the nucleon to the S11(1535) resonance is predominantly due to the exchange of the pi meson between the colliding nucleons.

Antiproton confinement in a Penning-Ioffe trap for antihydrogen

Antiprotons (p[over]) remain confined in a Penning trap, in sufficient numbers to form antihydrogen (H[over ) atoms via charge exchange, when the radial field of a quadrupole Ioffe trap is added. This first demonstration with p[over] suggests that quadrupole Ioffe traps can be superimposed upon p[over] and e(+) traps to attempt the capture of H[over] atoms as they form, contrary to conclusions of previous analyses.

First laser-controlled antihydrogen production

Lasers are used for the first time to control the production of antihydrogen (H ). Sequential, resonant charge exchange collisions are involved in a method that is very different than the only other method used so far-producing slow H during positron cooling of antiprotons in a nested Penning trap. Two attractive features are that the laser frequencies determine the H binding energy, and that the production of extremely cold H should be possible in principle-likely close to what is needed for confinement in a trap, as needed for precise laser spectroscopy.

First measurement of the velocity of slow antihydrogen atoms

The speed of antihydrogen atoms is deduced from the fraction that passes through an oscillating electric field without ionizing. The weakly bound atoms used for this first demonstration travel about 20 times more rapidly than the average thermal speed of the antiprotons from which they form, if these are in thermal equilibrium with their 4.2 K container. The method should be applicable to much more deeply bound states, which may well be moving more slowly, and should aid the quest to lower the speed of the atoms as required if they are to be trapped for precise spectroscopy.

Driven production of cold antihydrogen and the first measured distribution of antihydrogen states

Cold antihydrogen is produced when antiprotons are repeatedly driven into collisions with cold positrons within a nested Penning trap. Efficient antihydrogen production takes place during many cycles of positron cooling of antiprotons. A first measurement of a distribution of antihydrogen states is made using a preionizing electric field between separated production and detection regions. Surviving antihydrogen is stripped in an ionization well that captures and stores the freed antiproton for background-free detection.

Background-free observation of cold antihydrogen with field-ionization analysis of its states

A background-free observation of cold antihydrogen atoms is made using field ionization followed by antiproton storage, a detection method that provides the first experimental information about antihydrogen atomic states. More antihydrogen atoms can be field ionized in an hour than all the antimatter atoms that have been previously reported, and the production rate per incident high energy antiproton is higher than ever observed. The high rate and the high Rydberg states suggest that the antihydrogen is formed via three-body recombination.

[Laparotomy performed in pregnant women due to non-obstetrical causes]

OBJECTIVE

The clinical characteristics of laparotomy during pregnancy were investigated.

MATERIALS AND METHODS

A series of 24 cases of laparotomy during pregnancy was investigated with respect to clinicopathologic features and outcome.

RESULTS

Among 23 cases there were 20 ovarian tumors, 2 acute appendicitis and 2 uterine fibroid. Gestational ages at the time of surgery ranged from 16 to 24 weeks of patients with ovarian tumors and from 30 to 32 weeks in others. No intraoperative or postoperative maternal or fetal complications occurred. One patient had a stage III ovarian carcinoma and went to total hysterectomy, and other patient had a stage IA ovarian carcinoma.

CONCLUSIONS

Appendectomy can be performed without additional risk to the fetus for those who require surgical intervention during pregnancy. Ovarian surgery in pregnancy for persistent masses is important to obtain a final histologic diagnosis.

[Comparison of conservative and laparoscopic treatment of PCOS]

OBJECTIVE

Aim of study contained clinical analysis of results conservative (Clostilbegyt) and laparoscopic (electro-catheterisation of ovaries) methods of treatment PCOS. Authors analysed count of pregnancy, deliveries and serum concentrations of LH, FSH, LH/FSH ratio, 17 beta E2 before and after treatment.

MATERIAL AND METHODS

Stady included 50 obese patients (group A, BMI > 28) treated by Clostilbegyt and 50 lean patients (group B, BMI < 28) treated by laparoscopic ovarian electrocautery.

RESULTS

We found higher percentage of pregnancies (84%) and deliveries in group B (72%) versus A. We obtained statistically significant higher serum concentrations of LH, 17 beta E2 and LH/FSH ratio of group B versus A.

CONCLUSIONS

1. Recommendation method for treatment PCOS is a laparoscopic electro-catheterisation of ovaries. 2. This method stabilize hormonal secretion of hypothalamic-pituitary-ovarian axis in the PCOS.

[The evaluation of susceptibility to oxidation of selected lipoproteins of pregnant women with type B diabetes mellitus in 2nd and 3rd trimester of pregnancy]

OBJECTIVES AND DESIGN

The aim of study was estimation of susceptibility on the process of oxidation of selected lipoproteins of pregnant women with IDDM in II, III trimester of pregnancy.

MATERIALS AND METHODS

Study included 80 women. Patients were divided into four groups: pregnant with IDDM, pregnant healthy, nonpregnant with and without IDDM. We used spectrophotometric method for estimation of susceptibility on oxidation of HDL, LDL in the four groups of patients.

RESULTS

In the group of diabetic pregnant we found increased serum concentrations of LDL. The comparison of examined groups showed statistically significant higher susceptibility on the oxidation of chosen lipoproteins in pregnant with IDDM. This group of patients characterized lower antioxidation activity than other groups.

CONCLUSIONS

Diabetic pregnant characterized higher serum concentrations of LDL, and increase of peroxidation of lipids than other groups. This group showed lower total antioxidation activity. In the groups of diabetic women we obtained increased suspectibility of oxidation LDL and HDL.

[The method of treatment of functional evident hyperprolactinemia in sterile women]

OBJECTIVES AND DESIGN

The aim of study was evaluation of three methods of treatment of functional, evident hyperprolactinemia in women with primary or secondary sterility by use of Bromoergocriptine, Dopergin or Norprolac.

MATERIALS AND METHODS

Our study contained 65 patients divided into three groups treated by use three methods. We used RIA-method for evaluation serum concentrations of h-PRL. Authors estimated the impact of dopaminergic receptors D2 agonist on the serum concentrations of h-PRL before, in 2nd and 6th month of observation.

RESULTS

Authors obtained decrease serum concentrations of h-PRL in the three groups of patients during therapy and observation.

CONCLUSION

Norprolac characterized well efficiency, safety and low count of side effects during treatment of hyperprolactinemia.