75 research outputs found
A transition radiation detector and gas supply system for Alpha Magnetic Spectrometer
No full textThesis (S.M.)--Massachusetts Institute of Technology, Dept. of Physics, 2004.Includes bibliographical references (p. 89-99).This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Alpha Magnetic Spectrometer is an experiment that will be on the International Space Station for three years. It will look for anti-matter and dark matter. Supersymmetric dark matter could produce an excess in the 10-300GeV positron spectrum. A 10-6 separation of positrons from the more abundant protons is planned for this signal. A TRD (Transition Radiation Detector) has been designed to achieve these physics goals. Besides the radiator, the TRD is a gaseous detector that needs a gas system providing signal stability to 3%. The design, and construction of the TRD gas supply system is described with emphasis on the electronics control.Bilge Melahat Demirköz.S.M
FCNC transition of Sigma(Q) to nucleon
No full textAzizi, Kazem (Dogus Author) -- Conference full title: 35th International Conference of High Energy Physics, (ICHEP) 2010; Paris; France; SISSA; 22 July 2010 throught 28 July 2010.The loop level flavor changing neutral current transitions of the Sigma(b) -> nl(+)l(-) and Sigma(c) -> p l(+)l(-) are investigated in full QCD and heavy quark effective theory in the light cone QCD sum rules approach. Using the most general form of the interpolating current for E-Q, Q = b or c, the transition form factors are calculated using two sets of input parameters entering the nucleon distribution amplitudes. The obtained results are used to estimate the decay rates of the corresponding transitions
Semileptonic Bc to P-wave charmonia (Xc0,X c1,hc) transitions within QCD sum rules
No full textAzizi, Kazem (Dogus Author) -- Conference full title: International Workshop on Quantum Chromodynamics: Theory and Experiment Beppe Nardulli Memorial Workshop, QCD at WORK 2010; Martina Franca; Italy; 20 June 2010 through 23 June 2010The form factors of the semileptonic Bc→S(AV) ℓν(ℓ=τ,μ,e) transitions, where S and AV denote the scalar Xc0 and axial vector (Xc1,hc) mesons, are calculated within the framework of the three-point QCD sum rules. The results of form factors are used to estimate the total decay widths and branching ratios of these transitions. A comparison of our results on branching ratios with the predictions of other approaches is also presented.Italian Ministry of Education, University and Research (MIUR), Istituto Nazionale di Fisica Nucleare (INFN
An Example of the Modern Industrial Settlements of the Republic: The Cürek Social Facilities
No full textCumhuriyetin ilanıyla değişen siyasal yapı, toplumsal ve mekânsal değişimleri de beraberinde getirmiştir. Ekonomik açıdan kendi kendine yetebilme amacıyla sanayileşme alanında atılan adımlar, sanayinin merkezini batıdan orta Anadolu'ya yönlendirmiş; özellikle maden yataklarının olduğu kırsal bölgelerde sanayileşme devlet eliyle gerçekleştirilmiştir. 1930'lardan itibaren, zengin demir yataklarının bulunduğu Divriği de bu sanayi merkezlerinden biri olmuştur. Maden sahasının geniş bir alana yayıldığı bölgede Divriği merkezinden 17 km. uzaklıkta inşa edilen Cürek Sosyal Tesisleri, sahada ve tesislerde çalışan memur ve geçici süreli işçilerin ulaşım ve barınma sorununa çözüm getirirken, bölgenin yerel kimliğinden farklı ve yeni bir yerleşim dokusu yaratmış; Orta Anadolu kırsalında modern kent yaşamı deneyimini sağlamıştır. Demir madeni sanayisinin, süreç içindeki gelişimleri doğrultusunda, daha az iş gücü gerektiren bir teknolojiye kavuşması ve sanayi alanındaki özelleştirmelerin artmasıyla çalışma düzeni değişmiş; bu gelişmeler sonucunda, 1942 yılından itibaren yaklaşık 40 yıl boyunca maden işletmelerinin merkezi olan, Cürek Yerleşkesi yerini Divriği merkezine daha yakın bir bölgede yapılan yeni lojmanlara bırakmıştır. İçindeki yaşam sona erdikten sonra kaderine terkedilen tesisler, alınan tescil kararına rağmen koruma altında değildir. Cumhuriyet'in ulus-devlet anlayışıyla kurduğu ve Anadolu kırsalında modern kent yaşamına örnek teşkil etmesini amaçladığı Cürek Sosyal Tesisleri, cumhuriyetin endüstri mirasının değerli bir parçasıdır ve öneminin hatırlanması gerektiği görülmektedir. Bu araştırma, cumhuriyet döneminin kalkınma modeline örnek teşkil eden bu endüstri mirası alanının dünü ve bugününe ışık tutarak, yeniden hayata döndürülmesi için öneriler geliştirmeyi amaçlamaktadır.The political structure that changed with the proclamation of the Republic also brought about social and spatial transformations. In line with the goal of achieving economic self-sufficiency, steps were taken in the field of industrialization, redirecting the center of industry from the western regions to Central Anatolia. Particularly in rural areas rich in mineral resources, industrialization was carried out under state supervision. From the 1930s onward, Divriği, known for its abundant iron deposits, became one of these industrial hubs. The Cürek Social Facilities, built 17 kilometers away from the center of Divriği in a region where mining sites covered a vast area, addressed the transportation and housing needs of officers and temporal workers employed in the mines and facilities. It also introduced a new and distinct settlement pattern, differing from the local identity of the region, and provided an experience of a modern urban life in rural Central Anatolia. With the technological advancements in the iron mining industry requiring less labor and the increase in privatization in the industrial sector, the working system changed. As a result of these developments, The Cürek Social Facilities, which served as the center of mining operations for approximately 40 years starting in 1942, was replaced by new residential facilities built in an area closer to the center of Divriği. Despite being abandoned after the cessation of activities and receiving a heritage registration decision, the facilities have not been preserved. The Cürek Social Facilities, established under the Republic's nation-state ideology to serve as an example of modern urban life in rural Anatolia, are a valuable part of the modern heritage of the Republic and deserve renewed recognition of their significance. This study aims to shed light on the past and present of this industrial heritage site, which exemplifies the Republic's development model, and proposes strategies for its revitalization
Asymmetry parameter of K-1(1270,1400) by analyzing the B -> K-1 nu(nu)over-bar transition form factors within QCD
No full textSeparating the mixture of the K-1(1270) and K-1(1400) states, the B -> K-1(1270, 1400)nu(nu) over bar transition form factors are calculated in the three-point QCD sum rule approach. The longitudinal, transverse and total decay widths as well as the asymmetry parameter, characterizing the polarization of the axial K-1(1270, 1400) and the branching ratio for these decays, are evaluated
Semileptonic B-q -> D-q*l nu (q=s,d,u) decays in QCD sum rules
No full textThe form factors relevant to B-q -> D-q*(J(P) = 1(-))l nu (q = s, d, u) decays are calculated in the framework of the three point QCD sum rules approach. The heavy quark effective theory prediction of the form factors as well as 1/m(b) corrections to those form factors are obtained. A comparison of the results for the ratio of form factors at zero recoil limit and other values of q(2) with the predictions of the subleading Isgur-Wise form factor application for B -> D*l nu is presented. The total decay width and branching ratio for these decays are also evaluated using the q(2) dependencies of these form factors. The results are in good agreement with the constituent quark meson model and existing experimental data. The q = s case can also be detected at LHC in the near future
Improved fixed center approximation of the Faddeev equations for the (K)over-bar N N system with S=0
No full textWe extend the Fixed Center Approximation (FCA) to the Faddeev Equations for the K¯NN system with S=0, including the charge exchange mechanisms in the K¯ rescattering which have been ignored in former works within the FCA. We obtain similar results to those found before, but the binding is reduced by 6 MeV. At the same time we also evaluate the explicit contribution the πNΣ intermediate state in the three body system and find that it produces and additional small decrease in the binding of about 3 MeV. The system appears bound by about 35 MeV and the width omitting two body absorption, is about 50 MeV
Λ b → π - ( D s - ) Λ c ( 2595 ) , π - ( D s - ) Λ c ( 2625 ) decays and D N , D ∗ N molecular components
No full textFrom the perspective that Lambda(C)(2595) and Lambda(C)(2625) are dynamically generated resonances from the DN, D*N interaction and coupled channels, we have evaluated the rates for Lambda(b) -> pi(-)Lambda(C)(2595) and Lambda(b) -> pi(-)Lambda(C)(2625) up to a global unknown factor that allows us to calculate the ratio of rates and compare with experiment, where good agreement is found. Similarly, we can also make predictions for the ratio of rates of the, yet unknown, decays of Lambda(b) -> D-s(-)Lambda(C)(2595) and Lambda(b) -> D-s(-)Lambda(c)(2625) and make estimates for their individual branching fractions
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