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Nuclear Physics B Proceedings Supplement 00 (2014) 1–6
Nuclear Physics BProceedingsSupplement
How the HYPATIA analysis tool is used as a hands-on experience to introduceHEP to high schools
Christine Kourkoumelis and Stylianos Vourakison behalf of the ATLAS collaboration1
Physics Faculty and Institute of Accelerating Systems and Applications,University of Athens, Panepistimioupoli, Ilissia 15771, Greece
Abstract
“HYPATIA” is a tool for interactive analysis of data from the ATLAS experiment at the Large Hadron Collider ofCERN. It has been created by the authors and has been evolving over a number of years. It is available in a dowloadableversion, which is regularly used in the International Masterclasses, and an online version which now exists in the formof a webapp. Furthermore, the data from ATLAS, which are necessary for performing different educational analysispaths, are available online. Such examples of interactive analyses vary from the estimation of the magnetic field ofthe ATLAS solenoid magnet, to detecting “pseudo” Higgs events. These applications have been used in recent yearsin a large number of schools in the form of a half-day mini local (or even remote) masterclass. These activities havebeen supported by various European Union outreach programs which give emphasis to promoting science educationin schools through new methods based on the inquiry based techniques: questions, search and answers. This waywe have been able to introduce cutting edge research in particle physics to High Schools, bridging the gap betweenresearch and school hands-on experience.
Keywords: ATLAS, LHC, HYPATIA, ATLAS event analysis tool
1. INTRODUCTION1
Particle physics has rarely (if ever) been part of the2
high-schools curricula in most countries. The same3
is true to some degree about the ideas of modern4
physics in general. School curricula in most countries5
include only the basic physics concepts that have been6
known for centuries. The demonstrations/experiments7
available date back to the beginning of the 20th century.8
Moreover, no information is given about the modern9
research and the cutting-edge technologies. The10
European Union (EU) has long recognized the need of11
bridging the gap between school science education and12
pioneering research. Through the support of several13
1Email: [email protected] and [email protected]
EU outreach programs, the HYPATIA event tool [1]14
has been developed and implemented in several inquiry15
based education contexts. HYPATIA is an innovative16
hands-on event visualization tool which aims to intro-17
duce the students to the most modern particle physics18
research. It aims to stimulate students’ interest with19
science by involving them to interactive analysis of data20
from the ATLAS experiment [2] at CERN.21
22
The recent discovery of the Higgs boson has attracted23
large media coverage generating great public interest.24
The students, through the usage of HYPATIA, can try25
to “discover” the Higgs boson themselves. In addi-26
tion, their teachers get extensive help in their effort to27
explain the most recent experimental results, subjects28
which they have not been trained to explain. In this29
C.Kourkoumelis and S.Vourakis / Nuclear Physics B Proceedings Supplement 00 (2014) 1–6 2
way both students and teachers get engaged with playful30
learning of High Energy Physics (HEP).31
2. THE EU OUTREACH PROJECTS WHICH32
HELPED DEVELOP THE HYPATIA TOOL33
As mentioned in the introduction HY.P.A.T.I.A (HY-34
brid Pupils Analysis Tool for Interactions in ATLAS) is35
an event display for data collected by the ATLAS exper-36
iment at CERN. It has been developed at the University37
of Athens since 2007, in cooperation with the Belgrade38
Institute of Physics during the first years (2007-2010).39
The development was initially supported by the ATLAS40
outreach group, and subsequently by the following EU41
outreach projects:42
1) Learning with ATLAS@CERN (2009-2011) [3].43
This project was coordinated by one of the authors44
(C.K); its main objective was to use the information ma-45
terial and the data from the ATLAS experiment in order46
to build educational scenarios for schools and universi-47
ties. It formed a rich repository of HEP resources rele-48
vant to the ATLAS experiment [4]. This way it demon-49
strated and applied the innovative pedagogical approach50
of inquiry learning to communities of students, teachers51
and the general public.52
2) PATHWAY to inquiry based science education53
(2011-2013). The project focused on teachers and pro-54
posed a standard-based approach to teaching science,55
in general and not only HEP, by inquiry. It outlined56
instructional models, motivated the teachers to adopt57
inquiry based techniques and activities in their class-58
rooms, and offered access to a unique collection of open59
educational resources and teaching practices [5].60
3) Discover the COSMOS: e-Infrastructures for an61
Engaging Science Classroom (2010-2012) which was62
coordinated by one of the authors (C.K). The Discover63
the COSMOS activities introduced students to concepts64
and ideas of big science in the fields of Astronomy65
and HEP. During its two year course, it implemented66
a great number of activities that interconnected schools67
and research centers following a detailed pedagogical68
framework. The project developed an innovative learn-69
ing environment [6] which brings together more than70
95,000 science education learning objects and activi-71
ties connected to the science curriculum from Astron-72
omy, Space Physics and HEP. The consortium managed73
to mobilize an extremely large number of users (5,70074
teachers and approximately 31,000 students) and to in-75
volve them in numerous activities, at schools and at re-76
search centers.77
4) Go-lab [7]: Online science labs, started in Novem-78
ber 2012 for a four year duration. It goal is to open79
up the remote science laboratories, their data archives,80
and virtual models (“online labs” ) for large-scale use81
in education. Go-lab is addressed to students, teach-82
ers and lab-owners. During its first year of operation it83
has already created a pilot federation of several online84
labs from worldwide renowned research organizations85
(e.g., CERN, ESA) and from several selected universi-86
ties. Four HYPATIA scenarios which will be described87
in sections 4 and 5 are included in the Go-lab portal as88
Inquiry Learning Spaces (ILSs). The structure of each89
ILS is such that it includes all steps of the inquiry learn-90
ing methodology, namely : orientation, conceptualiza-91
tion, investigation, conclusion and discussion.92
5) Inspiring Science Education (ISE). The ISE93
project [8] began in April 2013 and will last till July94
2017. It aims at contributing to the implementation95
of the “Digital Agenda for Europe” in particular con-96
tribute to mainstreaming the eLearning for moderniza-97
tion of education and training. The ISE designs, plans98
and implements large-scale pilots to stimulate and eval-99
uate innovative use of existing eLearning tools and dig-100
ital resources for scientific disciplines and technology101
(STEM related subjects), enhancing science learning102
in 5,000 primary and secondary schools in 15 Euro-103
pean Countries. During its first year it has already104
reached 500 schools in Europe; all Greek schools par-105
ticipating in the pilot phase have received training in the106
HYPATIA HEP scenarios through mini-masterclasses107
(see 6.2).108
3. DESCRIPTION OF THE HYPATIA TOOL109
The full-featured offline version is based on the AT-110
LANTIS event display created by the University Col-111
lege London and Birmingham University teams of AT-112
LAS [9]. HYPATIA (Figure 1) offers a graphical repre-113
sentation of the products of proton collisions registered114
by the ATLAS detector. Students using the event dis-115
play can interact with the events and in this way study116
the fundamental building blocks of nature and their in-117
teractions. At the same time, they learn how the gigantic118
state-of-the-art detector works. This gives students an119
insight into the research being done at CERN and stim-120
ulates an enthusiastic interest in it and in possible sci-121
entific careers. The full version of HYPATIA has been122
used in the International Masterclasses (IMC) [10], [11]123
(see 6.1) unofficially since 2007 in Athens and officially124
since 2009 worldwide. It uses java and is therefore com-125
patible with most operating systems (Windows, Linux,126
OSX, Solaris). This version is updated every year with127
new functionality to better serve the IMC’ s needs as one128
of the two ATLAS exercises -the Z path [12]- evolves.129
C.Kourkoumelis and S.Vourakis / Nuclear Physics B Proceedings Supplement 00 (2014) 1–6 3
Figure 1: Offline version used in the International Masterclasses
The latest additions include the use of photons in or-130
der to study the H → γγ decays along with the cor-131
responding histograms and export functions for the re-132
sults. In the most recent HYPATIA-v7.4 2014 Mas-133
terclass version, the histograms of the decay products134
of H → ZZ → 4`, (` = e, µ) are plotted separately135
according to the type of lepton combination, namely136
4` = 2e2µ, 4µ, 4e). The offline version of HYPATIA is137
freely available at [13] along with event files, instruc-138
tions and supporting material. This version has also139
been used in the context of Nuclear Physics laboratory140
for 4th year undergraduate students at the University of141
Athens.142
In addition to the offline version, since 2010 the Uni-143
versity of Athens has developed an online version of144
HYPATIA [14] which is simpler to handle events and145
aimed squarely at educational use. The first iteration146
of the online version was implemented as a java applet147
and was used from 2010 until 2013. Due to the java148
requirement which limited the target use (not supported149
by mobile operating systems) and the increasing diffi-150
culty in supporting java in recent browser versions due151
to security concerns, a new iteration was developed in152
2014. This is implemented as a web application and is153
based on HTML5 and javascript which are supported by154
all operating systems, both pc based (windows, linux,155
etc) and mobile (android, ios, windows phone). In ad-156
dition, the new iteration does not require the installation157
of any additional software (such as java) and runs every-158
where out of the box. The web application is designed to159
be simpler to use than the offline version of HYPATIA,160
while still containing all the functionality necessary for161
the exercises. It is especially easy to explain to students,162
doesnt need any deployment in classrooms or computer163
laboratories and can be used in any device available,164
even tablets and smartphones. The web application (on-165
line) version of HYPATIA shown on Figure 2 is avail-166
able at [14] and includes event files for all exercises (Z,167
Higgs, Conservation of momentum and Magnetic field168
measurement), instructions (including videos), help, ex-169
ercise descriptions and solutions. Both the application170
and the supporting website are available in Greek, En-171
glish, German and French. The great advantage of the
Figure 2: New online version of HYPATIA written in Javascript andHTML5
172
web application is its flexibility and possibility of cre-173
ation of personalized exercises/labs by the instructor. It174
includes four different versions with increasing level of175
difficulty; level four (HYPATIA4) being the full version176
which permits the reconstruction and histogramming of177
the Z and Higgs bosons.178
4. HEP SCENARIOS OF HYPATIA179
As mentioned above, the Go-lab portal already in-180
cludes two full ILSs dedicated to the discovery of the181
Z0 [15] and Higgs boson [16] respectively. By following182
the ILSs step-by-step instructions are given to students183
and teachers, so that the scenarios can be performed in184
class without external help. A search for the Z0 and185
Higgs boson can also be performed using HYPATIA4186
online, but in this case the help of a HEP scientist (ei-187
ther visiting or remote) is necessary. The same is true188
for the offline version of HYPATIA, where the Z path189
instructions [12] have to be followed with external help.190
In the Z boson exercise the students study the Z0 →191
e−e+ and Z0 → µ−µ+ decays. They are guided to learn192
how to separate the characteristic signatures which the193
muons or the electrons leave in the ATLAS detector194
C.Kourkoumelis and S.Vourakis / Nuclear Physics B Proceedings Supplement 00 (2014) 1–6 4
by studying the event display in two mutually perpen-195
dicular views. After the identification of two opposite196
charged muons or electrons, the corresponding tracks197
are inserted into the invariant mass table and their invari-198
ant mass is automatically calculated. By studying the199
invariant mass histogram, mll, the user is instructed to200
determine whether she/he has found a “resonance” cor-201
responding to the mass of the Z0 boson, and in this202
way infer its existence. The histograms of the invariant203
masses of Z0 → 2e and Z0 → 2µ (mee and mµµ his-204
tograms) are also available, so the user can compare the205
two masses and their differences, if any. The user should206
also observe the finite width of the resonance and draw207
conclusions about the lifetime of the boson and the ex-208
perimental errors.209
The Higgs exercise builds upon the experience gained210
during the “Discover the Z boson” exercise. This time211
the students look at Higgs boson decays into four lep-212
tons (H → 4l) which can be two pairs of electron-213
positron or muon-antimuon or one of each. The user214
looks for two Z bosons in the event and inserts the de-215
cay products of each one into the invariant mass table.216
This way she/he can determine the mass and width of217
the Higgs boson2 through the corresponding mllll his-218
togram.219
5. THE HYPATIA SCENARIOS DIRECTLY220
CONNECTED TO THE SCHOOL CURRIC-221
ULA222
The Go-lab portal also contains two new scenarios di-223
rectly connected with the school curricula: these exer-224
cises have short duration, are aimed at younger students225
and can be easily implemented in the classroom in the226
course of one lesson plan.227
The first exercise, aims to demonstrate that the con-228
servation principles [17] apply to big science as well,229
namely from the macroscopic to the microscopic world.230
The cross-section of the ATLAS detector perpendicular231
to the proton beams (z-axis) is used to demonstrate the232
principle, since both before and after the collision, the233
total momentum is zero. In this exercise we use spe-234
cially selected and filtered events with very few charged235
tracks (muons, which are easily identifiable). The stu-236
dents should add up all momenta of the tracks either by237
vector addition or by adding the x,y components. The238
2The events contained in the “Higgs” online file are not real datafrom ATLAS but are “pseudo” events produced by overlapping tworeal Z events, therefore the mass of the few “Higgs” events comes outclose to 2mZ .
kinematic quantities of each track (direction, momen-239
tum) are given in the table shown in the lower left hand240
side of Figure 2. Then by calculating the vector oppo-241
site to the sum of the momenta of all particles, the stu-242
dents either confirm that it is almost zero (experimen-243
tal errors always exist in real data) or that a substantial244
amount of momentum is missing in a particular direc-245
tion. This may be an indication of an invisible neutrino.246
They can also compare the result of their calculation247
with the corresponding quantity calculated by the web248
app ETmiss and the direction of the resulting vector (in249
the x-y plane) to the red dotted line shown on the can-250
vas which is the corresponding quantity calculated by251
the webapp.252
The philosophy behind the second exercise [18] is to253
apply the Lorentz law of the force exerted on a particle254
by the magnetic field in order to calculate the strength of255
the magnetic field of the ATLAS solenoid surrounding256
the Inner Detector [2]. ATLAS measures the momen-257
tum of charged particles by bending them in the mag-258
netic field of its several magnets. The inner magnet is259
a superconducting solenoid creating an almost uniform260
field of 2 Tesla. The magnetic field lines are parallel261
to the beams, thus the tracks of the charged particles262
are bent by the Lorentz force in the x-y plane (trans-263
verse plane, plane of Figure 2). The force exerted in264
this plane is the centripetal force which is equal to the265
Lorentz force:266
(m ∗ v2T )/R = q ∗ vT ∗ B (1)267
where vT is the velocity of the charged particle calculate268
in the plane transverse to the colliding beams269
Taking as known the strength of the magnetic field in270
Tesla, the absolute value of the charge q and estimating271
the radius of curvature of the tracks R in meters, AT-272
LAS calculates the pT (the transverse component of the273
momentum) of the charged tracks:274
pT (GeV/c) = 0.3 ∗ R(m) ∗ B(T ) (2)275
In the exercise the user treats the pT as known (by276
selecting a track and looking at its value in the table277
shown in the lower left hand side of Figure 2. The R278
(arc radius) is calculated by HYPATIA by right clicking279
on three well separated points on the curved track and280
fitting a circle to it3. The result obtained by the user is281
the strength of the field in Tesla, since HYPATIA soft-282
ware solves equation (2) for B. After performing this283
3In order to have tracks which are bent within the 2.4 m diameterof the solenoid only charged tracks with transverse momenta between500-700 MeV/c appear in the list of tracks of this exercise.
C.Kourkoumelis and S.Vourakis / Nuclear Physics B Proceedings Supplement 00 (2014) 1–6 5
calculation for a small number of tracks, the user ob-284
tains the mean value of B and the instructor can pursue285
a discussion of statistics, outliers etc.286
6. ACTIVITIES FOR IMPLEMENTATION OF287
HYPATIA IN THE SCHOOL CLASS288
Since 2007 when the first of the five European289
projects was launched and the first offline version290
of HYPATIA was written, outreach teams from the291
consortium, the participating countries and beyond292
have been using HYPATIA in the context of master-293
classes, e-Masterclasses and mini-masterclasses. Sum-294
mer schools, teachers’s training sessions and contests295
have also been organized in the framework of the above296
mentioned EC projects to effectively support and dis-297
seminate the widespread use of the proposed activities298
in the participating countries and beyond (i.e. Australia,299
Canada, Bulgaria, U.S.A. etc).300
6.1. International Masterclasses301
The IMC organized each March by the International302
Particle Physics Outreach Group (IPPOG) [19] provide303
an opportunity for high school students and their teach-304
ers to be “scientists for a day”. Their goal is to famil-305
iarize the teachers and students with the cutting-edge306
research performed at CERN and in the LHC in partic-307
ular. Each year about 10,000 high school students from308
41 countries all over the world go to one of about 150309
nearby universities or research centres for one day in310
order to unravel the mysteries of particle physics by an-311
alyzing real data.312
During the day-long activity the local organizers313
(HEP scientists from universities or research centres)314
explain the ideas of particle physics and its importance315
in basic research while demonstrating the fundamentals316
of particle detector operation and explaining the way317
particles interact and leave characteristic signatures in318
the detectors according to their type.319
HYPATIA is used in the ATLAS Z path activity [12]320
of the IMC’ s. This is the most popular exercise used by321
67 institutes worldwide in 2014. The students use the322
HYPATIA offline tool and real events from the ATLAS323
detector in order to identify and study decays of short-324
lived particles such as Z0 → 2l, J/ψ → 2l, Y → 2l,325
H → 4l and H → 2γ decays. After the end of the326
event analysis, the students compare their results with327
those of students from about 5-6 other institutes which328
performed the same analysis, during a videoconference.329
6.2. Mini Masterclasses and e-Masterclasses330
The mini-masterclasses and e-masterclasses were pi-331
oneered by the Discover the COSMOS project and are332
smaller scale half-day masterclasses where the students333
can stay in their own school (or go to CERN) and334
are guided either remotely (by video-conferencing) or335
by a few visiting scientists with the simultaneous help336
from their trained teachers. For these masterclasses the337
students use the web application version of HYPATIA338
which allows easy use in any internet enabled device339
without the need for deployment. Usually these master-340
classes are accompanied by a virtual visit to the ATLAS341
control room. This way the students have the opportu-342
nity to see the scientists at work doing their shifts and343
discuss with them in a long question and answer ses-344
sion, following the presentation of the mini-experiment.345
Figure 3 shows a map of the very recent masterclasses346
performed in Greece during the last two years, which347
covered almost all regions of the country by visiting348
about 50 schools. Similar events were also performed
Figure 3: Mini masterclasses in Greece
349
in other European countries as well as at CERN, where350
students from four different countries came together for351
such events. Moreover, during the 2013 CERN Open352
Days, a large crowd of about 3,000 visitors came to the353
ATLAS stand and had hands on experience with the on-354
line HYPATIA tool as well as with MINERVA (Mas-355
terclass INvolving Event Recognition Visualised with356
Atlantis), Collider, LHC game and CERNland.357
C.Kourkoumelis and S.Vourakis / Nuclear Physics B Proceedings Supplement 00 (2014) 1–6 6
6.3. HYPATIA Teachers training during CERN exposi-358
tions359
In addition to summer schools a large number of HY-360
PATIA training workshops were organized during the361
visits of the CERN mini exposition in Greece as well as362
in Spain and Cyprus. The mini expo, for its 2011-2012363
tour, was upgraded with new posters, hands-on activities364
and combined with educational activities. In every one365
of its six stops in different Greek cities (Athens, Herak-366
lion, Patras, Alexandroupolis, Kavala and Volos) several367
local teacher workshops were organized, training more368
than 650 teachers.369
In the spring of 2014 the “Accelerating Sci-370
ence” CERN exposition came to Athens for a month.371
It was hosted at the premises of the Eugenideio Foun-372
dation (science museum and planetarium). The exhi-373
bition was a huge success with more than 11,000 visi-374
tors, among them 4,000 students from 92 schools. Also375
about 120 teachers were trained in the use of HYPATIA376
in three workshops held in parallel with the exhibition.377
7. Conclusions378
During the past two years a great effort has been379
made to exploit the recent publicity about CERN and380
the Higgs boson, in Greece and in Europe. The Inter-381
national Masterclasses, the mini Masterclasses and the382
two CERN exhibitions have helped thousands of people,383
ranging from the general public to students and their384
teachers to get acquainted with HEP and CERN. The385
number of European schools visiting CERN has risen386
significantly. More specifically the number of Greek387
schools visiting CERN during the past two years has388
increased by 23% from 2012 to 2013 and a further 31%389
from 2013 to 2014. CERN can no longer accommo-390
date them! Furthermore, an example of the impact that391
all those actions have had on Greek students and teach-392
ers, is the fact that Odysseus’ Comrades team from Var-393
vakios Pilot School in Athens were joint winners of394
the Beam line competition of CERN. The teacher who395
led the team, A. Valadakis, has been trained in the use396
of HYPATIA and participated with his students at sev-397
eral masterclasses. He has also brought his students at398
CERN several times. This is a great example of the im-399
pact of such actions extending beyond the classroom400
and the given exercises. It shows that under the right401
circumstances, students and teachers can build upon the402
knowledge they gain through those actions and eventu-403
ally construct their own exercises or experiments.404
8. Acknowledgments405
This research has been co-financed by the European406
Union (European Social Fund - ESF) and Greek na-407
tional funds through the Operational Program “Educa-408
tion and Lifelong Learning ” of the National Strate-409
gic Reference Framework (NSRF) - Research Fund-410
ing Program: THALES. Investing in knowledge society411
through the European Social Fund.412
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