LHCb Outreach example Ben Couturier (CERN) on behalf of the LHCb Collaboration. Frontiers of Fundamental Physics 14 Marseille July 15th to 18th 2014

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1 LHCb Outreach example Ben Couturier (CERN) on behalf of the LHCb Collaboration Marseille July 15th to 18th 2014

2 LHCb Collaboration 2

3 LHCb Detector Transverse Beam Single arm spectrometer Designed for the study of particles with beauty and charm quarks Precise particle identification and reconstruction See talks by Sam Cunliffe and Jeremy Dalseno 3

4 10th Edition in 2014 Discovery of Particle Physics for 15 to 19 year old students Get an insight into topics and methods of basic research and the fundamentals on matters and forces : 28 countries, 130 sites, 6000 students! For the first time with a LHCb Measurement 4

gathered by particle physics experiments Participate in

5 The Masterclass day: Students go to a nearby University or research centre Perform measurements on real data gathered by particle physics experiments Participate in an international video conference for discussion of results 5

6 Measurement of D0 meson lifetime Educational goals: Understand how we build histograms and detect signal Understand how to derive signal characteristics in presence of background 6

7 Measuring the D0 Lifetime at LHCb KD p π+ 0 p D0 meson D0 lifetime: 410,1 +/- 1.5 fs (according to the Particle Data Group) Charm quark Up antiquark D0 Typically travels ~ 3mm before decay in LHCb Vertex Locator Decays to K- π+ in ~3.9% of cases (2 body decay easy to track in the LHCb detector) Looking for (K,π) pairs originating from a displaced vertex 7

8 Charm production at LHCb 10% of LHC interactions produce a charm hadron! LHCb has already reconstructed more than 1 billion signal charm decays 8

9 The exercise itself 1. Build mass histogram and identify signal Using the event display to search for displaced vertices File with 30 D0 K π candidates Looks for displaced vertices Plot D0 mass histogram Teachers gather histograms between students 2. Measure the D0 lifetime Fitting the lifetime and improving S/N ratio by cutting on the D 0 Impact parameter File with 54k candidates Identify Signal region Fit mass and lifetime Study the effect of various cuts 9

10 1. Signal finding: Event Display C++ Application using the ROOT framework ( 10

11 1. Signal finding: Event Display 11

12 1. Signal Finding: In the detector Transverse Beam Need to zoom in around the interaction region! 12

13 1. Signal finding: Zoom on the Vertex locator Projections: Close-up: Step 1: Find Vertex 13

14 0 1. Signal finding: D mass histogram Step 2: Invariant mass Step 3: Add to histogram 14

15 0 1. Signal finding: D Mass histogram 15

16 2. Lifetime fit: Data Use D0 Kπ events from 2012 data Analysis requires background subtraction in signal region 16

17 2. Lifetime fit: Fitting the mass 17

18 2. Lifetime fit: Plotting the distributions Signal region 18

19 2. Lifetime fit ps!!!!! ~15% off compared to Particle Data Group value, we have a systematic bias 19

20 2. Lifetime fit: Event selection The events can be selected based on a number of parameters: D0 transverse momentum D0 calculated lifetime D0 Impact parameter with primary vertex Kπ+ D0 p IP p 20

21 0 2. Lifetime fit: effect of cut on D IP PDG Value 21

22 2. Lifetime fit: D from B rejection We have D0 coming from B meson decays! The Impact parameter cut is a good way to reject them PDG Value 22

LHCb Masterclasses 2014 Seven LHCb Masterclass days in March 2014 19 Institutes ~600 students

Suceava, Bologna, Clermont-Ferrand, Marseille, NIKHEF, CERN (a school from Annecy), Dortmund,

23 LHCb Masterclasses 2014 Seven LHCb Masterclass days in March Institutes ~600 students Cincinnati, Syracuse, Ferrara, Marseille, Pisa, LAL Orsay, Warwick, Milano, Padova, Firenze, Suceava, Bologna, Clermont-Ferrand, Marseille, NIKHEF, CERN (a school from Annecy), Dortmund, LPNHE Paris, Bucharest Great success! Very positive feedback! A few glitches but they didn't spoil the fun! 23

24 Lessons learned Fun and rewarding exercise! High interest from the students The Video conference was appreciated too (opportunity to ask questions) Commitment of local LHCb Members is crucial Local organization, Installation/test of the software Need to make the Software as easy and portable as possible Commitment of teachers is also vital Preparation of the exercise with their pupils is needed to make the most of the exercise! 24

25 Technical considerations LHCb Production famework could not be reused Started exercise from the Masterclass code from Alice C++ Application ROOT framework ( Advantages Known framework Supports all platforms Drawbacks Requires build/local installation for each platform 25

(Games framework) Web based, also runs on tablets and

26 Future Event Display Collaboration with the CERN Media labs TeV (Total event Visualizer) Unity Player based (Games framework) Web based, also runs on tablets and smartphones... TeV Prototype LHCb Collision ATLAS Camelia 26

CP Violation) New institutes/schools are welcome to join Contact: vladimir.

27 The Future Technical improvements on the way for 2015 Masterclasses Looking into new measurements (e.g. CP Violation) New institutes/schools are welcome to join Contact: And the tools and data are not just for Masterclasses... Can be used for Summer schools... Exercise available on the LHCb website 27

28 Acknowledgments Many thanks to: The other members of the LHCb Masterclass team: Tom Blake, Vladimir Gligorov, Moritz Karbach, Bolek Pietrzyk, Ana Trisovic The ALICE experiment for sharing their Masterclass code with us The IPPOG Committee The local organizers (and their institutes) as well as the teachers The students for their enthusiasm! For more info: 28

High Precision Measurements of Track-segments of Ionising Particles with GridPix Detectors

High Precision Measurements of Track-segments of Ionising Particles with GridPix Detectors Wilco Koppert Nikhef, Amsterdam Detector R&D January 18, 2012 Wilco Koppert (Nikhef) High Precision Measurements