SELEX (SEGMENTED LARGE-X BARYON SPECTROMETER) Fermilab 96-97 11/29/2010 SELEX (SEGMENTED LARGE-X BARYON SPECTROMETER) Fermilab 96-97 11/29/2010 Emrah Tiras, University of Iowa Emrah Tiras, Uni. of Iowa

Emrah Tiras, University of Iowa 11/29/2010 Outline SELEX E781 Physical Goals of SELEX SELEX Collaboration SELEX Experimental Setup Detector Overview Spectrometers Conclusion 11/29/2010 Emrah Tiras, University of Iowa Emrah Tiras, Uni. of Iowa

11/29/2010 SELEX is a fixed target experiment at Fermilab which took data during the year 96-97 with 600 GeV Σ−, π− during two years of running it recorded 15.2 billion hadronic interaction events. is a multistage charged particle spectrometer with high acceptance of Feynman X- Parameter. 11/29/2010 Emrah Tiras, University of Iowa Emrah Tiras, Uni. of Iowa

Physical goals of the SELEX The study of; the lifetime of weakly decaying charmed baryons. the charmed baryon production in the 600 GeV hyperons' beam. the excited baryons. the charm baryon semileptonic decay. charm baryon spectroscopy both charm and non-charm physics. 11/29/2010 Emrah Tiras, University of Iowa

SELEX Experiment Collaboration 125 participants from 20 institution in 11 countries (USA, Russia, Turkey, Brazil, China, Germany, Israel, Mexico, UK and Italy) 11/29/2010 Emrah Tiras, University of Iowa

The SELEX Experiment Setup is consisted of; a beam line a target area a multistage spectrometer The SELEX experiment used the Fermilab charged Hyperon beam which is composed of 50% Σ⁻ and 50% π⁻ with the energy of about 600 GeV for negative polarity; and 92% p and 8% π⁺ with the energy of 540 GeV for positive polarity. The beam was run at the forward production angle(Θ=0˚) The experiment was designed to have high acceptance and resolution in Xf region 0.1<Xf<1. 11/29/2010 Emrah Tiras, University of Iowa

Schematic view of SELEX spectrometers Hyperon Magnet X Exit M1 Magnet M2 Magnet M3 magnet Targets Beam Z M1 spectrometer M2 spectrometer M3 spectrometer Beam Spectrometer Vertex Spectrometer The beam spectrometer is between the exits of the hyperon magnet and target region. The vertex spectrometer is between the targets and M1 spectrometer. The M1,M2,M3 spectrometers are located after the corresponding analyzing magnets. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa SELEX Detector Layout 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Detector Overview 1 (The SELEX Exp. had an extensive particle identification system) Vertex Silicon Strip Detector (SSD): The heart of the experiment with 4 µm transverse position resolution at 600 GeV. Beam Transition Radiation Detector(TRD): Beam particles (Σ⁻/π⁻, p/π⁺) were tagged 3000 phototube Ring Imaging Cherenkov Counter (RICH): identify the secondary particles: electrons, muons, pions, kaons, protons, and even hyperons. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Detector Overview 2 The Electron Transition Radiation Detector (ETRD): to separate electrons from hadrons which is important for the semileptonic decay physics. Three lead glass detectors: to identify and measure the energy of the photons and electrons. SELEX also has a precise tracking system and 3 analyzing magnets to measure particle momentum. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Analyzing magnets SELEX apparatus has 3 analyzing magnets that were used to measure track momentum. Name Z [cm] Aperture [cm]*[cm] B [kG] Pt [GeV] M1 190 61*51 11.98 0.73 M2 745 61*25 14.66 0.84 M3 4240 6.85 0.42 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa SPECTROMETERS The SELEX experiment was composed of five stage spectrometer Beam Vertex M1 M2 M3 Each spectrometer other than Vertex which is designed to create high resolution tracking near target, contained a bending magnet. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Beam Spectrometer is consisted of; the hyperon production target the hyperon magnet the beam particle identification detectors beam tracking detectors and scintillators 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa M1 Spectrometer is made up of; a magnet with 1.3 T magnetic field which gives a transverse momentum. 2 large area silicon micro-strip detectors (LASD) measure the beam and primary and secondary vertex tracks. proportional wire chambers (PWC) measure the momenta of the tracks. drift chambers (DC) a photon calorimeter (Lead Glass Electromagnetic Calorimeter) 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa M1 Spectrometer was designed to analyze the particles from 2.5 to 15 GeV/c momentum range. Low energy particles(from the vertex region) are tagged and photon energies are measured at this stage. This plays a crucial role in measuring the momentum of upstream trucks. This was built here (University of Iowa) 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa M2 Spectrometer is consisted of; a magnet with 1.5 T magnetic field. LASDs 7 PWCs with 2 mm wire spacing 6 Vector Drift Chambers (explanation on the next slide) 2 hodoscopes 6 Electron Transition Radiation Detector(ETRD) were designed to give good electron identification. Ring Imaging Cherenkov (RICH) detector. Provides the particle identification information for the hyperons' daughter particles. is designed to identify particles with momentum higher than 15 GeV/c 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa M3 Spectrometer is consisted of; a magnet with 1.3 T. 2 Multiwire Proportional Chambers(PWC) 3 Vector Drift Chambers; Were designed to provide the short track segments of downstream decay products, charged particles as well as the position information. a photon Calorimeter a neutron Calorimeter was built jointly by the University of Iowa and the Trieste groups. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Vertex Spectrometer starts at the downstream end of the last target and ends at the middle of the M1 spectrometer. is consisted of 20 Vertex Silicon Detectors(SSDs) mounted to five station, four SSDs at each. the first 8 detectors, called 5 cm-detectors, have 20 µm pitch and 5.1*5.0 cm² active area. The downstream 12 detectors, called mosaic detectors, have 25µm pitch and 8.3*3.2 cm² active area. Each of the detectors has greater than 98% hit detection efficiency and spatial resolution about 6.5 µm. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Conclusion First time the doubly charmed baryon Ξcc⁺ was interpreted from the experiment: Ξcc⁺ Λc⁺K⁻π⁺ In 2002, the SELEX collaboration published evidence of a doubly charmed baryon Xi (Ξcc), containing two charm quarks. They figured out a new particle decaying in two modes: DsJ ⁺ D˚K DsJ ⁺ Dsη New measurements for D˚ and D⁺ lifetimes τ₁: (409.6±1.1±1.5)fs τ₂: (1039.4±4.3±7.0)fs Precision measurements of the Ξc⁺ and D˚ and Ds lifetimes. Production asymmetry of Ds from 600 GeV/s Σ and π beam. At that time all these new experimental data had good agreement with theory. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Additional 42 graduate students in Physics completed their thesis with this experiment(data) from 1997-2010. 8 graduate students from here. http://www-selex.fnal.gov/documentation/thesis Some useful articles about the experiment. Precision measurements of the [Lambda]c⁺ and D˚ lifetimes Phys. Rev. Let. 86, 5243 (2001). Measurement of the Ds lifetime Physics Letters B 523 (2001), 22-28. Production Asymmetry of Ds from 600 GeV/c Sigma⁻ and pi⁻ beam Physics Letters B 558 (2003), 34-40. 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa References Akgun, U.: CMS HF Calorimeter PMTs and Ξc+ Lifetime Measurement (University of Iowa, 2003) Ayan, A.S.: The CMS Forward Calorimeter Prototype Design Studies and Ωc0 Search at E781 Experiment at Fermilab ( University of Iowa, 2004) Fermi National Accelerator Laboratory [Internet]. 2003. Chicago: Fermi National Accelerator Laboratory SELEX Collaboration; 2003 [cited 2003 Aug 8]. Available from: http://www-selex.fnal.gov High Energy Physics Division (HEPD) of Petersburg Nuclear Physics Institute (PNPI) of Russian Academy of Sciences [Internet]. 2010. Russia: High Energy Physics Division; 2010 [cited 2010 Nov 1]. Available from: http://dbserv.pnpi.spb.ru/hepd/activities/hep.html 11/29/2010 Emrah Tiras, University of Iowa

Emrah Tiras, University of Iowa Thank you for listening to my presentation… Emrah Tiras 11/29/2010 Emrah Tiras, University of Iowa