SELEX SEGMENTED LARGEX BARYON SPECTROMETER Fermilab 96 97

SELEX (SEGMENTED LARGE-X BARYON SPECTROMETER) Fermilab 96 -97 11/29/2010 Emrah Tiras, University of Iowa 1

Outline �SELEX E 781 �Physical Goals of SELEX �SELEX Collaboration �SELEX Experimental Setup �Detector Overview �Spectrometers �Conclusion 11/29/2010 Emrah Tiras, University of Iowa 2

SELEX � is a fixed target experiment at Fermilab which took data during the year 96 -97 with 600 Ge. V 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 3

Physical goals of the SELEX Ø The study of; § § § 11/29/2010 the lifetime of weakly decaying charmed baryons. the charmed baryon production in the 600 Ge. V hyperons' beam. the excited baryons. the charm baryon semileptonic decay. charm baryon spectroscopy both charm and non-charm physics. Emrah Tiras, University of Iowa 4

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 5

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 Ge. V for negative polarity; and 92% p and 8% π⁺ with the energy of 540 Ge. V 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 6

Schematic view of SELEX spectrometers Hyperon Magnet Beam Exit X M 1 Magnet Targets M 1 spectrometer Beam Spectrometer M 2 Magnet M 3 magnet Z M 2 spectrometer M 3 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 M 1 spectrometer. The M 1, M 2, M 3 spectrometers are located after the corresponding analyzing magnets. 11/29/2010 Emrah Tiras, University of Iowa 7

SELEX Detector Layout 11/29/2010 Emrah Tiras, University of Iowa 8

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 Ge. V. �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 9

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 10

Analyzing magnets � SELEX apparatus has 3 analyzing magnets that were used to measure track momentum. Name Z [cm] Aperture [cm]*[cm] B [k. G] Pt [Ge. V] M 1 190 61*51 11. 98 0. 73 M 2 745 61*25 14. 66 0. 84 M 3 4240 61*51 6. 85 0. 42 11/29/2010 Emrah Tiras, University of Iowa 11

SPECTROMETERS �The SELEX experiment was composed of five stage spectrometer �Beam �Vertex �M 1 �M 2 �M 3 �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 12

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 13

M 1 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 14

M 1 Spectrometer �was designed to analyze the particles from 2. 5 to 15 Ge. V/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 15

M 2 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 Ge. V/c 11/29/2010 Emrah Tiras, University of Iowa 16

M 3 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 17

Vertex Spectrometer �starts at the downstream end of the last target and ends at the middle of the M 1 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 18

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: �Ds. J ⁺ D˚K �Ds. J ⁺ 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 Ge. V/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 19

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 Ge. V/c Sigma⁻ and pi⁻ beam Physics Letters B 558 (2003), 34 -40. 11/29/2010 Emrah Tiras, University of Iowa 20

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 Ωc 0 Search at E 781 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 21

Thank you for listening to my presentation… Emrah Tiras 11/29/2010 Emrah Tiras, University of Iowa 22