1 / 17

Photoproduction of K + L(1405) near threshold

Photoproduction of K + L(1405) near threshold. Main features of the reaction Kinematics K + meson identification TAPS calibration for charged particles MC simulation conditions Results Summary. V.L. Kashevarov, CB@MAMI Collaboration Meeting, Basel 2006. g p → K + L (1405).

byron-ewing
Download Presentation

Photoproduction of K + L(1405) near threshold

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Photoproduction ofK+L(1405)near threshold • Main features of the reaction • Kinematics • K+ meson identification • TAPS calibration for charged particles • MC simulation conditions • Results • Summary V.L. Kashevarov, CB@MAMI Collaboration Meeting, Basel 2006

  2. g p → K+L(1405) • L(1405) (or L*)mass = 1406.5 MeV • Threshold = 1454.97 MeV • Full width = 50  2 MeV • L*decay modes:So po (33%),S+p- (33%),S- p+ (33%) • Final particles to be detected: (1)K+L* { So [L ( po n ) g ]po } 11.9% (2)K+L* {So [L ( p-p ) g ]po } 21.1% (3)K+L* { S+ ( p o p ) p- } 17.2% (4)K+L*{ S+(p+n ) p- } 15.8% (5)K+L* { S- ( p-n ) p+ } 33.3%

  3. Kinematics • E g= 1455 – 1507 MeV K+ Ekin (MeV) Q (deg) Ekin (MeV) vs Q (deg)

  4. (1)So{ L (po n) g} po g po n po Ekin (MeV) vs Q (deg)

  5. (2)So{ L (p- p) g} po po g p p- Ekin (MeV) vs Q (deg)

  6. (3)S+ (p o p) p- po p- p Ekin (MeV) vs Q (deg)

  7. (4)S+(p+n) p- p- p+ n Ekin (MeV) vs Q (deg)

  8. (5)S- (p-n) p+ p+ p- n Ekin (MeV) vs Q (deg)

  9. K+meson identification in TAPS Time of flight (ns) Cluster energy (MeV)

  10. TAPS calibration for charged particles K+ E kin(MeV) p p+ Cluster Energy (MeV) p+ p K+ E kin(MeV) Time of flight (ns)

  11. TAPS calibration for charged particles K+ E kin(MeV) p p+ Cluster Energy (MeV) p+ p K+ E kin(MeV) Time of flight (ns)

  12. MC simulation conditions • Endpoint tagger: Eg = 1455 – 1507 MeV • Tagger bin = 2 MeV • Ladder = 800 kHz (Main tagger from 900 MeV) • Tagging efficiency = 0.4 • Live time = 60% • LH2 target length = 5 cm • Front of TAPS – Center of target = 120 cm • Old PID and MWPC, but without any materials in forward direction • No Cherenkov detector • Total cross section for 1480 MeV = 100 nb

  13. Results E K+ = F (E cluster) E K+ = F (ToF) E g = 1475 MeV MM ( g, K +) - M L*(MeV)

  14. Results (1)K+ L* { So[ L ( p o n ) g ] p o} Partial contribution = 0.8% (0.06%) (2)K+ L* { So [ L ( p -p) g ] p o} 1.8% (0.13%) (3)K+L* { S+ ( p o p ) p- } 4.8% (0.25%) (4)K+L*{ S+(p+n ) p- } + (5)K+ L* { S- ( p -n) p+}2.8% (0.45%) 10.2% (0.9%) MM ( g, K +) - M L*(MeV)

  15. Results : InvMass (1)K+ L* { So[ L ( p on ) g ] p o} Partial contribution = 0.6% (2)K+ L* { So [ L ( p -p) g ] p o} 0.8% 1.4% L ( pon ) So ( po n g ) L* ( po n g po ) L ( p-p ) So ( p- p g ) L* ( p-p g po )

  16. Results : InvMass (3)K+L* { S+ ( p o p ) p- } 2.4% (4)K+L*{ S+(p+n) p-} + (5)K+ L* {S- ( p -n)p+}4.2% 6.6% S+ ( po p) L* ( po p p-) S+ ( p+ n) + S- ( p -n ) L* ( p+n p-)

  17. Summary • The best way for investigation of the reaction is to measure MM( g ,K+); • Coincidences between K+ and two or three final state particles are needed to suppress background; • Endpoint tagger would be very useful; • TAPS detector allows to do a good identification of K+ mesons for cluster size < 3 and cluster energy < 200 MeV; • Missing mass resolution: 25 MeV; • Detection efficiency: 10.2 %; • Expected yield: 0.1 events/nb/h.

More Related