The Standard Model

Standard Model - Source: Wikipedia

 The Standard Model of particle physics is the theoretical framework that describes the fundamental building blocks of the universe and the forces through which they interact. It is one of the most successful and rigorously tested theories in modern physics.

Here is a breakdown of how the universe is put together according to the Standard Model.

1. The Building Blocks: Matter Particles (Fermions)

All tangible matter in the universe is made up of particles called fermions, which have half-integer spin (e.g., 1/2). These are divided into two main categories, each split into three "generations" of increasing mass.

Quarks

Quarks are heavy particles that experience the strong nuclear force. They combine to form composite particles called hadrons (like protons and neutrons).

• Generation 1: Up (u), Down (d) — These make up ordinary stable matter.

• Generation 2: Charm (c), Strange (s)

• Generation 3: Top (t), Bottom (b)

Leptons

Leptons do not feel the strong nuclear force.

• Generation 1: Electron (e^-), Electron Neutrino (ν_e)

• Generation 2: Muon (μ), Muon Neutrino (ν_μ)

• Generation 3: Tau (τ), Tau Neutrino (ν_τ)

Note: For every matter particle, there is a corresponding antimatter particle with the same mass but opposite electric charge (e.g., the positron is the antielectron).

2. The Messengers: Force Carriers (Gauge Bosons)

Particles interact by exchanging force-carrier particles called gauge bosons, which have integer spin (e.g., 1). The Standard Model accounts for three of the four fundamental forces of nature:

Force	Description	Gauge Boson (Carrier)	Mass / Range
Electromagnetism	Governs atomic structure, light, and chemical reactions.	Photon (γ)	Massless / Infinite
Strong Nuclear Force	Binds quarks inside protons/neutrons and holds atomic nuclei together.	Gluon ($g$)	Massless / Short-range
Weak Nuclear Force	Responsible for radioactive decay (like beta decay) and initiating solar fusion.	W+ / W- and Z0 Bosons	Very heavy / Ultra short-range

3. The Mass Giver: The Higgs Boson

The Higgs Boson (H) is a scalar boson (spin 0) associated with the Higgs field, which permeates the entire universe.

• Mechanism: As fundamental particles move through this field, they interact with it. The strength of this interaction determines the particle's inertial mass.

• Particles like the top quark interact strongly and are very heavy; photons do not interact with it at all and remain massless.

• Its discovery at CERN's Large Hadron Collider (LHC) in 2012 was the final piece confirming the Standard Model's framework.

What the Standard Model Left Out

While incredibly robust, the Standard Model is known to be an incomplete theory of nature because it fails to explain a few massive cosmological puzzles:

• Gravity: It does not include general relativity. The hypothetical carrier of gravity, the graviton, has not been incorporated mathematically into the quantum framework.

• Dark Matter & Dark Energy: The model only accounts for about 5% of the energy-mass composition of the observable universe. The remaining 95% is completely unaccounted for.

• Neutrino Mass: In the original mathematical formulation of the Standard Model, neutrinos are massless. However, oscillation experiments have proved they possess tiny, non-zero masses.

• Matter-Antimatter Asymmetry: It doesn't fully explain why the universe today is overwhelmingly made of matter, even though the Big Bang should have produced equal amounts of matter and antimatter.

Muon Neutrinos Transform to Electron Neutrinos

Super Kamiokande is the worldʼs largest underground neutrino detector,
and is located 1000 metres underground in Kamioka Mine, Hida, Gifu Precture, Japan.
Credit: Image courtesy of Stony Brook University

Yesterday at the European Physical Society meeting in Stockholm, the international T2K collaboration announced definitive observation of muon neutrino to electron neutrino transformation. In 2011, the collaboration announced the first indication of this process, a new type of neutrino oscillation, then; now with 3.5 times more data this transformation is firmly established. The probability that random statistical fluctuations alone would produce the observed excess of electron neutrinos is less than one in a trillion. Equivalently the new results exclude such possibility at 7.5 sigma level of significance. This T2K observation is the first of its kind in that an explicit appearance of a unique flavor of neutrino at a detection point is unequivocally observed from a different flavor of neutrino at its production point.

More info: sciencedaily and Stony Brook University

HST2012, CERN - Day 6

In this day we had two lectures. One lecture was about the latest discoveries (top quark, bottom quark and tau neutrino); the second lecture was about the Principle of Uncertainty. I don't want to bored you with this stuff. So lets talk about our first visit: LINAC 2. We went to the restricted area with radiation control and watch the place where Physics started. Everything started with a tiny Hydrogen bottle. The H2 goes to a chamber where the electrons are retain and protons are "synchronized". After that the protons are injected to a linear accelerator and goes to LEIR. Look here:

 

The Standard Model of Particle Physics

LHC physics data taking gets underway at new record collision energy of 8TeV

At 0:38 CEST this morning, the LHC shift crew declared ‘stable beams’ as two 4 TeV proton beams were brought into collision at the LHC’s four interaction points. This signals the start of physics data taking by the LHC experiments for 2012.  The collision energy of 8 TeV is a new world record, and increases the machine’s discovery potential considerably.

(font CERN)

• Press Release: LHC physics data taking gets underway at new record collision energy of 8TeV
• Video: CERN News - Physics restarts in the LHC at new record energy
• CERN: LHC bate novo recorde mundial de energia

The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, which mediate the dynamics of the known subatomic particles.

Still, the Standard Model falls short of being a complete theory of fundamental interactions because it does not incorporate the physics of dark energy nor of the full theory of gravitation as described by general relativity. The theory does not contain any viable dark matter particle that possesses all of the required properties deduced from observational cosmology. It also does not correctly account for neutrino oscillations (and their non-zero masses). Although the Standard Model is believed to be theoretically self-consistent, it has several apparently unnatural properties giving rise to puzzles like the strong CP problem and the hierarchy problem.

Nevertheless, the Standard Model is important to theoretical and experimental particle physicists alike. For theorists, the Standard Model is a paradigmatic example of a quantum field theory, which exhibits a wide range of physics including spontaneous symmetry breaking, anomalies, non-perturbative behavior, etc. It is used as a basis for building more exotic models which incorporate hypothetical particles, extra dimensions and elaborate symmetries (such as supersymmetry) in an attempt to explain experimental results at variance with the Standard Model, such as the existence of dark matter and neutrino oscillations. In turn, experimenters have incorporated the Standard Model into simulators to help search for new physics beyond the Standard Model.

Recently, the Standard Model has found applications in fields besides particle physics, such as astrophysics, cosmology, and nuclear physics.

(in Wikipedia)

You can read another posts about particles and Higgs in my blog. Now, watch this videos about Standard Model:

week and month review

Posts this week:

• The Power of a Solar Storm  Mar 26, 2012
• More questions about the origins of the Moon  Mar 26, 2012
• Projectile Motion with Angry Birds  Mar 26, 2012
• How Large is the Universe  Mar 28, 2012   
• Double Slit Experiment   Mar 28, 2012  
• Solar Tornado   Mar 30, 2012
• Current and Voltage   Mar 31, 2012

TOP 5 this week:

1. Solar Tornado  Mar 30, 2012
2. More questions about the origin of the Moon   Mar 26, 2012
3. The Power of a Solar Storm  Mar 26, 2012
4. How Large is the Universe  Mar 28, 2012
5. Projectile Motion with Angry Birds  Mar 26, 2012

TOP 5 this month:

1. Measure the Speed of Light with Chocolate
2. Great Sun spot 
3. Neutrino's Saga - final chapter?
4. Torus in a galactic nucleus
5. Angry Birds Space: NASA announcement

Week review

Posts this week:

• The Comets Tale (Playlist)  Mar 17, 2012
• Neutrino's Saga - final chapter?  Mar 16, 2012
• The Evolution of the Moon  Mar 15, 2012
• Great Sun Spot  Mar 14, 2012   
• Torus in a galactic nucleus  Mar 13, 2012  
• Angry Birds Space: NASA announcement  Mar 13, 2012

TOP 5 this week:

1. Great Sun spot  Mar 14, 2012   [HOT post]
2. Torus in a galactic nucleus  Mar 13, 2012
3. Neutrino's Saga - final chapter?  Mar 16, 2012
4. Angry Birds Space: NASA announcement  Mar 13, 2012
5. The Scale of the Universe 2  Mar 12, 2012

Neutrino's Saga - final chapter?

Time of flight difference between the speed of light and the arriving neutrinos. Observe a great difference between the two experiments. Now, we have to wait for the new results of the OPERA experiment, after the cable's problem.

The ICARUS experiment uploaded a paper to the arXiv website with a preprint paper about the neutrinos' velocity, in October 2011, defying the superluminal neutrinos. Now, after the assumption of a problem in a cable, by the OPERA team, ICARUS published a preprint paper that confirms the previous results that neutrinos doesn't travel with a speed superior that the speed of light. 

So, we have to wait for the OPERA results (we need a large number of events and it takes... days), to confirm that neutrinos aren't superluminal.

Here is the abstract:

Measurement of the neutrino velocity with the ICARUS detector at the CNGS beam

The CERN-SPS accelerator has been briefly operated in a new, lower intensity neutrino mode with ~10^12 p.o.t. /pulse and with a beam structure made of four LHC-like extractions, each with a narrow width of ~3 ns, separated by 524 ns. This very tightly bunched beam structure represents a substantial progress with respect to the ordinary operation of the CNGS beam, since it allows a very accurate time-of-flight measurement of neutrinos from CERN to LNGS on an event-to-event basis. The ICARUS T600 detector has collected 7 beam-associated events, consistent with the CNGS delivered neutrino flux of 2.2 10^16 p.o.t. and in agreement with the well known characteristics of neutrino events in the LAr-TPC. The time of flight difference between the speed of light and the arriving neutrino LAr-TPC events has been analysed. The result is compatible with the simultaneous arrival of all events with equal speed, the one of light. This is in a striking difference with the reported result of OPERA [1] that claimed that high energy neutrinos from CERN should arrive at LNGS about 60 ns earlier than expected from luminal speed. 

 Read more in DiscoverMagazine.com, CNet and Wired. 

Week review

Posts this week:

• The Scale of the Universe 2
• Daya Bay find new kind of neutrino transformation
• DARPA Cheetah Sets Speed Record for Legged Robots
• Earth from Space
• Deep exploits: the quest for dark matter
• Star formation by collapse of molecular clouds
• Great websites
• Higgs Boson: Latest Update
• Don't think atomic nucleus' as static
• Curved Paths

Top Posts this week:

PostsMore » Higgs Boson: Latest Update Mar 7, 2012,  Earth from Space Mar 7, 2012 Star formation by collapse of molecular clouds Mar 7, 2012 Daya Bay find new kind of neutrino transformation Mar 8, 2012 Don't think atomic nucleus' as static Mar 6, 2012

•