96 research outputs found

    Stopped nucleons in configuration space

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    In this note, using the simplified colour string model, we study the configuration space distribution of stopped nucleons in heavy-ion collisions. Given this model, we find that the stopped nucleons from the target and the projectile end up separated from each other by a distance which increases with the collision energy. In consequence, for the center-of-mass energies larger than 6 or 10 GeV (depending on the details of the model), it appears that the stopped nucleons are not necessarily in thermal and chemical equilibrium, and the net-baryon density reached is likely not much higher than that already present in the colliding nuclei

    Diffractive dissociation as shadow scattering

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    It is pointed out that if the mechanism of diffractive production of particles is the same as that of elastic scattering, the diffractive dissociation can be calculated as shadow of non-diffractive processes. A general method of calculation is proposed. It uses the technique of the overlap matrix. A specific calculation in Uncorrelated Jet Model is performed. In this calculation the diffractive processes arise as a direct consequence of correlations induced in non-diffractive interactions by energy and momentum conservation. The most important prediction of the model is that the inclusive mass distribution of diffractive dissociation splits into non-scaling part describing the low-mass excitations and the approximately scaling part describing the high-mass excitations. The non-scaling part of the mass spectrum is dominated by single particle production and at large masses behaves as dσ/dM2M6d\sigma /dM^{2}\sim M^{-6}. The shape of the scaling part of the spectrum in the triple-Regge region is dσ/dζ=(ζlogζ)1d\sigma /d\zeta = (\zeta log\zeta)^{-1} where ζ=M2/s\zeta = M^{2}/s. The properties of exclusive diffractive channels are also discussed

    Finite size of hadrons and Bose-Einstein correlations

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    It is observed that the finite size of hadrons produced in high energy collisions implies that their positions are correlated, since the probability to find two hadrons on top of each other is highly reduced. It is then shown that this effect can naturally explain the values of the correlation function below one, observed at LEP and LHC for pairs of identical pions

    Rising plateu from longitudinal phase-space

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    Longitudinal phase-space is used to study the energy dependence of the plateau in the rapidity distribution of particles produced in p–p collisions at laboratory momenta above 100 GeV. The density of particles emitted at 90^{\circ} in cms shows a fast rise until 10 000 GeV and then approaches the asymptotic limit very slowly. This rise accounts for a large fraction of the experimentally observed increase

    The longitudinal phase-space integral with leading particles

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    De Groot’s method of calculating the longitudinal phase-space integrals is generalized to include leading particles. The generalization simplifies practical calculations of all quantities predicted by the uncorrelated jet model with leading particles

    Asymmetric fireballs in symmetric collisions

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    This contribution reports on the results obtained in the two recently published papers [A. Bialas, A. Bzdak, K. Zalewski, Phys. Lett. B710, 332 (2012), A. Bialas, K. Zalewski, Acta Phys. Pol. B 43, 1357 (2012)] demonstrating that data of the STAR Collaboration show a substantial asymmetric component in the rapidity distribution of the system created in central Au–Au collisions, implying that boost invariance is violated on the event-by-event basis even at the mid c.m. rapidity

    Synchronous extraskeletal Ewing's sarcoma/PNET and gallbladder carcinoma : a case report and literature review

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    Ewing’s sarcoma (ES) and primitive neuroectodermal tumour (PNET) are now considered to be the same tumour and usually occur in long bones. Extraskeletal Ewing’s sarcoma is an extremely rare neoplasm, accounting for 1% of soft tissue sarcomas, with most common location in the thorax. Gallbladder cancer (GBC) represents the most common type among the biliary tract cancers with a poor prognosis even among patients undergoing aggressive therapy. We present study of extraskeletal ES/PNET found in the hilus of the liver of an elderly, diagnosed one month prior with GBC woman. The patient underwent two cycles of chemotherapy SAIME/SAVAC for ES and thereafter was operated. During three-year follow-up no recurrence of ES/PNET has been reported. However, two years after chemotherapy the patient suffered a relapse of adenocarcinoma of the gallbladder and thus received palliative chemotherapy of gemcitabine and cisplatin. After 16 months of recurrence she died. To the best of our knowledge, this is the first case of ES/PNET located in the hilus of the liver and as a synchronous neoplasm

    Laparoscopic transperitoneal lateral adrenalectomy for malignant and potentially malignant adrenal tumours

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    BACKGROUND: Laparoscopic adrenalectomy is still controversial in cases where malignancy is suspected. However, many proponents of this technique argue that in the hands of an experienced surgeon, laparoscopy can be safely performed. The aim of this study is to present our own experience with the application of laparoscopic surgery for the treatment of malignant and potentially malignant adrenal tumours. METHODS: Our analysis included 52 patients who underwent laparoscopic adrenalectomy in 2003–2014 due to a malignant or potentially malignant adrenal tumour. Inclusion criteria were primary adrenal malignancy, adrenal metastasis or pheochromocytoma with a PASS score greater than 6. We analyzed the conversion rate, intra- and postoperative complications, intraoperative blood loss and R0 resection rate. Survival was estimated using the Kaplan-Meier method. RESULTS: Conversion was necessary in 5 (9.7 %) cases. Complications occurred in a total of 6 patients (11.5 %). R0 resection was achieved in 41 (78.8 %) patients and R1 resection in 9 (17.3 %) patients. In 2 (3.9 %) cases R2 resection was performed. The mean follow-up time was 32.9 months. Survival depended on the type of tumour and was comparable with survival after open adrenalectomy presented in other studies. CONCLUSIONS: We consider that laparoscopic surgery for adrenal malignancy can be an equal alternative to open surgery and in the hand of an experienced surgeon it guarantees the possibility of noninferiority. Additionally, starting a procedure with laparoscopy allows for minimally invasive evaluation of peritoneal cavity. The key element in surgery for any malignancy is not the surgical access itself but the proper technique
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