1 / 8

Advancements in High-Level Triggers for B-Physics: Status and Future Plans

This document outlines the current status and future plans for High-Level Triggers (HLT) in the B-Physics group, led by Simon George. It discusses algorithm development focused on event selection and filtering, emphasizing physics-driven strategies. Key performance criteria include momentum thresholds and efficiency evaluations. The document details robust trigger algorithms, ongoing work, and collaboration with offline groups to refine cuts and enhance the B-physics trigger system. The aim is to produce a viable Technical Proposal showcasing substantial advancements in trigger methodologies.

naida
Download Presentation

Advancements in High-Level Triggers for B-Physics: Status and Future Plans

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. High Level Triggers forB Physics:Status and plans by Simon George for the HLT B-physics group

  2. PESA group • Physics and Event Selection Algorithms • algorithm development for high level triggers • increased emphasis on event filter • event selection strategy • physics driven • DAQ/HLT Technical Proposal March 2000

  3. B-physics HLT group • Aim for TP is to demonstrate a viable B-physics trigger. • Criteria for performance evaluation: • pT(e) > 1 GeV • pT() > 4 GeV • pT(/K) > 1.5 GeV • Efficiency: absolute and w.r.t. offline selection • Rate for B  X + pile up events • Time on standard machine for B  X + pile up events • Other issues • LVL2/EF boundary • Architecture implications • Robustness w.r.t. occupancy (luminosity, noise)

  4. Current Status • Work is documented in TPSR, Phys TDR, ATLAS notes. • Mostly done with offline code: • LVL2 muon trigger (muon detector track, ID track, matching) • LVL2 tracking with modified Xkalman • e/h separation using ID track + TR + ECAL •  identification pT > 3 GeV using muon detector + barrel HCAL • Baseline concept has been demonstrated and strategies developed, but offline reconstruction is too optimistic • Emphasis now switching to development of more trigger-like algorithms

  5. Trigger Algorithms • TRT scan (LUT) • TRT scan • initial search from Xkalman • interesting alternative ‘unbinned’ search • Si Hough/histo/fit • Si Kalman • Pixel scan • Full Xkalman++ • reference algorithm for LVL2 • for integrated EF studies

  6. TRT scan with LUT • Hough transform to histogram in (1/pT, 0) space • transformations for each straw in lookup table for speed • track candidates = maxima in histogram • Performance •  pT > 1 GeV, || < 2.5  mean efficiency 85% • no. of track candidates high in overlap region • Timing results • P-II 300 MHz / FPGA 50 MHz • Data: bbX+mb (low lumi)

  7. Event Filter • Need to show cuts that reduce rate from LVL2 (~840 Hz) to 100 Hz. • Two approaches: • Start with inclusive triggers like LVL2, e.g. J/  e+e- • which cuts can be tightened? • new cuts? e.g. vertex, impact parameter • Start with offline cuts • which cuts could be loosened? • look for common selections inclusive EF selections • This will need close interaction with the B-physics group.

  8. Summary • B-physics trigger is a very active area of study • Working towards Technical Proposal • We will benefit from close contact with offline group. • Some projects may be of particular interest, e.g. • Trigger/Offline comparison • LVL2 muon/inner detector track association • Event Filter cuts • http://hepunx.rl.ac.uk/atlasuk/simulation/level2/Bphys

More Related