A new look at the proton
September 11, 2007
The HERMES experiment (HERA measurement of spin). This photo shows that the entire experiment is mounted on rails and can be moved out of the ring of the particle accelerator (HERA). At the bottom left of the photo a piece of tube from the accelerator can be seen through which the electrons move (to the right).
Dutch researcher Paul van der Nat investigated more than three million collisions between electrons and protons. In his PhD thesis he demonstrates -for the first time– that the spin contribution of quarks to the proton can be studied by examining collisions in which two particles (hadrons) are produced.
The spin of a particle can most easily be compared to the rotating movement of a spinning top.
In the HERMES experiment at the HERA particle accelerator in Hamburg, physicists are investigating how the spin of protons can be explained by the characteristics of their building blocks: quarks and gluons.
Van der Nat investigated a method to measure the contribution of the spin of the quarks to the total spin of the proton, independent of the contribution of the spin of the gluons. For this a quark is shot out of the proton by an electron from the particle accelerator, as a result of which two hadrons are formed.
The direction and amount of motion of these two hadrons is accurately measured. This method, which Van der Nat applied for the first time, turned out to be successful.
Spin is a characteristic property of particles, just like matter and electrical charge. Spin was discovered in 1925, by the Dutch physicists Goudsmit and Uhlenbeck. In 1987, scientists at CERN in Geneva discovered that only a small fraction of the proton's spin is caused by the spin of its constituent quarks.
The HERMES experiment was subsequently set up to find this missing quantity of spin, and has been running since 1995. It is expected that spin will play an increasingly important role in many applications. The MRI scanner is a well-known example of an application in which the spin of protons plays a key role.
Source: NWO
-
New tool for proton spin
May 06, 2011 |
4.5 / 5 (2) |
2
-
Unique new probe of proton spin structure at Relativistic Heavy Ion Collider
Feb 15, 2011 |
5 / 5 (10) |
4
-
How does the proton get its spin?
Feb 17, 2010 |
4.3 / 5 (33) |
17
-
A new look at the proton
Sep 25, 2007 |
4.2 / 5 (31) |
0
-
End of an era at HERA accelerator
Jul 02, 2007 |
4.2 / 5 (5) |
0
-
Engineers build first sub-10-nm carbon nanotube transistor
Feb 01, 2012 |
4.9 / 5 (33) |
30
-
Something old, something new: Evolution and the structural divergence of duplicate genes
Jan 31, 2012 |
4.6 / 5 (7) |
1
-
The hidden nanoworld of ice crystals: Revealing the dynamic behavior of quasi-liquid layers
Jan 30, 2012 |
5 / 5 (4) |
1
-
Stock market network reveals investor clustering
Jan 27, 2012 |
3.9 / 5 (23) |
8
-
Of microchemistry and molecules: Electronic microfluidic device synthesizes biocompatible probes
Jan 26, 2012 |
5 / 5 (2) |
0
-
what makes two sounds similar???
1 hour ago
-
What would happen when a jet travelling at Mach 10 experiences engine failure
7 hours ago
-
Rust from my microwave ruined a nice bowl of soup and also my day
9 hours ago
-
gas leaks in space
13 hours ago
-
Weight required to balance a boom stand?
14 hours ago
-
Questions about Equivalence principle & Einstein Elevator?
16 hours ago
- More from Physics Forums - General Physics
More news stories
Explained: Sigma
It's a question that arises with virtually every major new finding in science or medicine: What makes a result reliable enough to be taken seriously? The answer has to do with statistical significance -- but ...
Feb 09, 2012 |
5 / 5 (20) |
76
Quantum physicist explains $100K offer for proof scaled-up quantum computing is impossible
(PhysOrg.com) -- MIT researcher Scott Aaronson has certainly riled the physics community with his offer this past Friday, of $100,000 to anyone who can prove that scaled-up quantum computing is impossible. ...
Diamond light, brighter than the sun
Its the size of five football pitches and generates light 10 billion times brighter than the sun. As the Diamond Light Source celebrates its tenth anniversary this year, Penny Bailey visits one of the ...
Feb 07, 2012 |
4.4 / 5 (9) |
18
|
Physicists 'record' magnetic breakthrough
An international team of scientists has demonstrated a revolutionary new way of magnetic recording which will allow information to be processed hundreds of times faster than by current hard drive technology.
Feb 07, 2012 |
4.6 / 5 (43) |
14
|
Hints of the Higgs - papers are submitted
Back in December 2011, the ATLAS and CMS experiments at CERN presented some exciting results that provided tantalising hints of the Higgs boson.
Feb 08, 2012 |
4.3 / 5 (8) |
10
Scientists discover molecular secrets of 2,000-year-old Chinese herbal remedy
For roughly two thousand years, Chinese herbalists have treated Malaria using a root extract, commonly known as Chang Shan, from a type of hydrangea that grows in Tibet and Nepal. More recent studies suggest that halofuginone, ...
New method to examine batteries -- MRI from the inside
There is an ever-increasing need for advanced batteries for portable electronics, such as phones, cameras, and music players, but also to power electric vehicles and to facilitate the distribution and storage of energy derived ...
Google might launch Drive for cloud storage soon
(PhysOrg.com) -- Google's next big move, according to the Wall Street Journal, is a cloud storage service called Drive. Hardly first to the plate, Google is simply catching up to introducing its cloud reposi ...
Lab study raises questions over nano-particle impact
Tests involving chickens have raised questions about the impact on health from engineered nano-particles, the ultra-fine grains commonly used in drugs and processed foods, scientists said on Sunday.
A mitosis mystery solved: How chromosomes align perfectly in a dividing cell
Although the process of mitotic cell division has been studied intensely for more than 50 years, Whitehead Institute researchers have only now solved the mystery of how cells correctly align their chromosomes during symmetric ...
Starve a virus, feed a cure? Findings show how some cells protect themselves against HIV
A protein that protects some of our immune cells from the most common and virulent form of HIV works by starving the virus of the molecular building blocks that it needs to replicate, according to research published online ...