# Presentation: 577774

## Heavy Quark Measurements with the LDRD Detector

- Hubert van Hecke, P-25
- Outline:
-   - Physics with the LDRD detector
-   - Rate estimates
-   - Performance

## Physics Motivation

- Why heavy study quarks in heavy-ion collisions?
-  - c, b quarks are all newly produced, early in the collision
-  - they probe the plasma as they emerge from the collision
-  - c, b quarks are heavy: QCD calculations are tractable
-  - decay to e, μ allow unique identification against a large background

**Notes:**
Give summary of whe heavy quarks are interesting in heavy ions
Ho precision measurements of c, b at forward y distinguish models:
  - energy loss effects
  - cold nuclear matter effects
  - model Eloss, flow simultaneously

Need scale on phenix
Use y or angle?
New plolt from Ivan

## Heavy Quark Signal Extraction with LDRD

-                             μ + X’

**Heavy Quark Signal Extraction with LDRD**

- Separation of prompt, short-lived, and long-lived decays allows one to pull out the signal from the background.

- D, B->mu

**Notes:**
Show semi-leptonic decay channel for D, B
Show components of single muon spectrum
Indicate what DCA cuts do to the spectra

## Detector Operation

- Measuring Charm and Beauty
- D, B mesons travel ~1 mm (with boost) before semi-leptonic decay to muons
- By measuring DCA to primary vertex, can separate D and B from prompt particles and long-lived decays like , K

## Detector Simulation

- 50x400 um pixels

-  Need resolution better than typical decay length (~100um)
-  Need occupancy low enough to find tracks in central AuA (<few %)
-  Need enough hits to reconstruct a track (>=3 hits)
-  Need to match tracks with Muon System

- Requirements:

-  Full, detailed detector simulation
-  Digitize hits, find clusters, find cluster centroids
-  Use Kalman Filter fitter to project track back to the vertex
-  Get DCA components in x(good), y(less good)
-  Sufficient resolution to separate prompt, heavy and light meson decays

- Current
- Simulation:

## Detector Performance

- -  Resolution is sufficient to allow separation of charm and beauty from prompt and long-   lived decays.
- -  Believe we can also separate Charm from beauty

## Heavy Quark Signal Extraction with FVTX

- Place cut  DCAmin < DCA < DCAmax

- Before: pi, K dominate:
- Signal/background <1

- After: signal/background>1 for both D and B ->mu

## Physics Rates

- Muons from D --> μX and B-->μX, in to the LDRD detector, for 1.1 pb-1 Au+Au

- B-->X

- D-->X

- Total 2.4e5

- Total 2.6e4

## Physics Measurements

- Improved error bars will allow us to distinguish between models of heavy quark propagation in AuAu collisions

- *Xiaorong Wang

**Notes:**
Green Djordjevic, gyulassi, xxx vogt
Blue
Yellow: ivan D+B

## Analysis Software Status and Outlook

- We have all simulation tools:
- 	p-p, Au-Au, single-particle event generators
- 	detailed and flexible detector model
- 	detector performance analysis code
- We have most offline software:
- 	merge MC data into offline data analysis stream
- 	combine with other Phenix systems
- 	Kalman Filter track reconstruction package
- Software components needed:
- 	track finder: start with existing barrel track finder (~4 FTE months)
- 	alignment calibration software: start with existing muon chamber
- 	software (~4 FTE months)
- 	real-time system monitoring software: start with existing
- 	code (~1 FTE months)
-               physics analysis once real data arrives

## Slide 11

## Separating Charm and Beauty

- Beauty measurements by:
- event topology cuts in single muon events
- kinematic cuts (pT, DCA fits)

- Direct Beauty Measurement

- Event Topology

- Charm/Beauty pT

- *Michael Malik

## Physics Measurements

- Try to get RAA measurement with expected luminosity for LDRD, theory plots overlaid

- *Xiaorong Wang

## Detector Performance

- 0.28% max detector occupancy allows for track finding in all conditions
- 3 or more hits in LDRD over most of its acceptance

- In these central Au+Au events, the busiest chip sees 8/2816 pixels on. (Min bias: 2, p+p: 0.02)

**Notes:**
Remove barrel

## Detector Specifications

- Need resolution better than typical decay length (~100um)
- Need occupancy low enough to find tracks in central AuA (<few %)
- Need enough hits to reconstruct a track (>=3 hits)
- Need to match tracks with Muon System