High Performance computing in Particle Physics

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• High Performance computing in Particle Physics
  Cosmology
• Application to Neutrino Parameters Correlations
• Nidal CHAMOUN
• Department of Physics,
• HIAST,
• Damascus, Syria

HIAST
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Table of Contents

• Basics
• Need for Powerful Computing in High Energy
  Physics
• Art of Cosmological Simulations
• The LHC Grid
• Neutrino Parameters model with many free
  parameters

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Powerful Computing in High Energy Physics

• Theoretical particle physics is an integral part
  of the world-wide activities to search for new
  physics beyond the Standard Model of High Energy
  Physics.
• In order to distinguish signs of non-standard
  physics from our present description of
  elementary particle interactions it is mandatory
  to have theoretical predictions originating from
  the underlying theory alone from a priori
  computations and without further approximations

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Powerful Computing in High Energy Physics

• Several applications in computational particle
  physics are still far beyond the reach of
  state-of-the-art computers, whenever following
  the evolution of even simple dynamics equations
  responsible for very complex behavior requires
  inordinately long execution times.
• For instance, In the approach of Lattice Gauge
  Theory the continuum of nature is replaced with a
  discrete lattice of space-time points.

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Powerful Computing in High Energy Physics

• This lattice approximation allows for numerical
  simulations on massively parallel computer
  architectures.
• Furnished with this conceptual tool, the high
  precision experimental data as expected from the
  newly planned accelerators can be interpreted in
  a clean manner not suffering from any built-in
  approximations.
• However, despite its space-time economy, the
  lattice needs the power of the world's largest
  supercomputers to perform the calculations that
  are required in the complex problem of solving
  the complicated equations describing elementary
  particle interactions.

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Powerful Computing in High Energy Physics

• This is the case when we integrate, say, over
  configuration space of a three-dimensional
  lattice system of too many sites, requiring up to
  Tera Monte Carlo steps, which is still an
  untreatable task.
• Extensive use of parallelism is the main avenue
  to boost computer performance.

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Art of Cosmological Simulations

• During the last 10 years new extensive
  observations of the Universe were made using both
  ground-based telescopes and space instruments.
• The huge observational progress has been
  accompanied by considerable effort in our
  theoretical understanding of the formation of
  different components of the observed structure of
  the Universe galaxies and their satellites,
  clusters of galaxies, and super-clusters.
• the standard
• cosmological model

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Art of Cosmological Simulations

• A substantial part of this theoretical progress
  is due to the improvement of numerical methods
  and models, which mimic structure formation on
  different scales using a new generation of
  massive parallel supercomputers.
• The nonlinear evolution of cosmological
  fluctuations can be studied only numerically. The
  details of galaxy formation must be followed
  using hydrodynamic simulations.
• However, many features can already be studied by
  semi-analytical methods

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Art of Cosmological Simulations

• Modern astrophysics and cosmology are
  characterized by dealing with complex problems
  whose dynamical range covers extended space-time
  scales, ranging from stability of solar systems
  to physics of quasars and large scale
  structures. .
• Thus, the requirements for modern cosmological
  simulations are extreme
• a very large dynamical range for force resolution
  and many millions of particles are needed.

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Art of Cosmological Simulations

• Case study Helium and deuterium abundances as
  a test for the time variation of the fine
  structure constant and the Higgs vacuum
  expectation value,
• J. Phys. G Nucl. Part. Phys. 34 (2007) 163176,
  by Chamoun, Mosquera, Landau Vucetich

We used semi-analytical methods (1991 Astrophys.
J. 378, 50418) to calculate the abundances of
helium and deuterium produced during Big Bang
nucleosynthesis assuming the fine structure
constant and the Higgs vacuum expectation value
may vary in time
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Time Variation of Fundamental Constants ??
Nucleosynthesis
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Time Variation of Fundamental Constants ??
Nucleosynthesis

• We assumed that the discrepancy between SBBN
  estimation for 4He and D and their observational
  data is due to a change in time for the
  fundamental constants the Higgs vev v, the fine
  structure constant a.
• We analysed the dependence of the 4He and D
  abundances on these fundamental constants within
  perturbation theory and on deviations with
  respect to the mean value of the baryonic density

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Time Variation of Fundamental Constants ??
Nucleosynthesis

• The calculation of the heavier elements
  abundance requires much more computations and
  coupled equations to be solved.

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Table of Contents

• Basics
• Need for Powerful Computing in High Energy
  Physics
• Art of Cosmological Simulations
• The LHC Grid
• Neutrino Parameters model with many free
  parameters

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The Grid What is it?
processing power on demandlike electrical power
a virtual metacomputer for the seamless access to
dispersed resources
coordinated resource sharing and problem solving
in dynamic, multi-institutional, virtual
organizations
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The GridVirtual Organizations
VO2
VO1
group of individuals or institutes who are
geographically distributed but appear to
function as one single unified organization
Internet
O1
O3
O2
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The Grid What is it?
reality is catching up fast with the dream

• Distributed computing a method of computer
  processing in which different parts of a program
  run simultaneously on two or more computers that
  are communicating with each other over a network.
  It is a type of segmented or parallel computing.
  It also requires that the division of the program
  take into account the different environments on
  which the different sections of the program will
  be running.

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What the Grid can do ?
What type of applications will the Grid be used
for?
the first big-time users of the Grid will
probably be scientists with challenging
applications that are simply too difficult to do
on just one set of computers.
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Computational problems

• Degree of parallelism ability to split into
  many smaller sub-problems that can be worked on
  by different processors in parallel
• Degree of granularity dependence of each
  sub-problem on the result of other sub-problems.

• As a rule of thumb, fine-grained calculations are
  better suited to big, monolithic supercomputers
• On the other hand, parallel calculations
  (high-throughput computing) are ideal for a more
  loosely-coupled network of computers.

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Large Hadron Collider Computing Grid project at
CERN

• To study the fundamental properties of subatomic
  particles and forces

Brookhaven National Laboratory (US) Fermi
National Accelerator Laboratory (Fermilab)
(US) Forschungszentrum Karlsruhe (Germany)
Rutherford Appleton Laboratory (UK)
CCIN2P3 (France) INFN-CNAF (Italy) SARA/NIKHEF
(Netherlands)
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Grid _at_ CERN

• CERN has a reputation for being at the forefront
  of networking technology - "where the Web was
  born" is the lab's motto. When it comes to Grid
  technology, this is particularly true CERN is
  leading some of the most ambitious Grid projects
  in the world
• The Large Hadron Collider (LHC), to run fully
  in autumn 2009, will smash particles, protons to
  protons with nearly the speed of light to create
  conditions that occurred a few seconds after the
  Big Bang.

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Need for Grid Computing in LHC

• These collisions will happen at an unprecedented
  energy of 14 trillion electron volts. The beam
  collisions would reveal physics beyond the
  Standard Model.
• Once operational we shall collect data of the
  order of 15 Petabytes (15 million Gigabytes)
  every year. That is more than 1000x the amount of
  information in book form printed every year
  around the world , and nearly 1 of all
  information that humans produce on the planet
  each year - including digital images, photos
• This data shall be used by thousands of
  scientists from all around the world.

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The LHC Computing Grid

• One of the challenges that this scenario shall
  pose would be to build and maintain data storage
  and provide analysis infrastructure for the
  entire high energy physics community.
• The current model adopted at the LHC includes a
  four-tier Grid Structure which shall distribute
  data worldwide. Formal access to the NWIC Grid is
  requested, in support of these activities.
• This LHC Computing Grid, launched on October 3,
  2008, is a distribution network where The data
  stream from the detectors provides approximately
  300 GB/s, filtered for "interesting events",
  resulting in a "raw data" stream of about 300
  MMB/s.
• The CERN computer center, considered the "Tier
  0" has a dedicated 10 Gb/s connection to the
  counting room

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Large Hadron Collider Computing Grid project at
CERN

• the LHC at Geneva produces roughly 15 Petabytes
  (15 million Gigabytes) of data annually. This
  data are accessed by the high energy physics
  community throughout the world

multiple copies of data and automatic reassigning
of computational tasks to available resources
ensures load balancing of resources and
facilitates access to the data
5000 scientists from about 500 research
institutes and universities
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•                
•                   
• MINSP (Short for Minimization of String
  potential)
• country Syria
• author Nizar Alhafez
• institute HIAST
• domain Theoretical Physics
• contacts nzhafez_at_hiast.edu.sy
• description We seek a minimum for a potential
  function (coming from the physics of string
  theory), involving many parameters. One run (when
  fixing different parameters) lasts for between 3
  to 10 hours, and hence the application needs
  (when we change parameters in the given regions)
  more than 15 years thinking to run the
  application on one machine.
• requirements The application requires
  AXIONsoftware. It has been installed on EUMEDGRID
  e-Science

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Table of Contents

• Basics
• Need for Powerful Computing in High Energy
  Physics
• Art of Cosmological Simulations
• The LHC Grid
• Neutrino Parameters model with many free
  parameters

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Neutrino Physics

• Neutrinos (meaning "Small neutral ones") are
  elementary particles that often travel close to
  the speed of light, lack an electric charge, are
  able to pass through ordinary matter almost
  undisturbed and are thus extremely difficult to
  detect. Neutrinos have a minuscule, but nonzero
  mass.

• The establishment of a non-vanishing neutrino
  mass in
• neutrino oscillation experiments is one of the
  major new
• Achievements in theoretical physics in the last
  decade.

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Neutrino experimental constraints

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A Model for Neutrino Mass Matrix

• Zero minors of the neutrino mass matrix,
  PHYSICAL REVIEW D 78, 073002 (2008), by Lashin
  Chamoun
• We examine the possibility that a certain class
  of neutrino mass matrices, namely, those with two
  independent vanishing minors in the flavor basis,
  regardless of being invertible or not, is
  sufficient to describe current data.

• Strategy spanning the free parameters in their
  accepted ranges,
• and test whether or not there are acceptable
  choices meeting the
• current data constraints.

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Neutrino Mass Matrix
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Neutrino Mass Matrix
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Neutrino Mass Matrix
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Neutrino Model with two vanishing minors
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What about One Vanishing Minor Neutrino Mass
Matrix

• A work in progress
• Less constraints ?More free parameters
• Need to span a larger space ? need a more
  powerful computer
• Can deduce correlations among the different
  parameters

• Strategy Again, the nature of nested loops
  suggests the possibility
• of using a distributed computing program which is
  split up into parts
• that run simultaneously on multiple computers
  communicating over
• a network .

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Neutrino Model with 1-vanishing minor

• We obtain acceptable points (here, \rho
  \sigma) for fixed
• acceptable choices of given parameters (here
  \delta). However, I
• Need to span \delta over its whole admissible
  range.

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Table of Contents

• Basics
• Need for Powerful Computing in High Energy
  Physics
• Art of Cosmological Simulations
• The LHC Grid
• Neutrino Parameters model with many free
  parameters

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Discussion