Merge pull request #54 from RaoOfPhysics/master

Changes to research description
2026-06-27 17:29:55 +08:00 · 2014-08-12 21:48:35 +02:00
parent 2ed2be50fd 26b47bb44a
commit bbd5a9050c
9 changed files with 66 additions and 51 deletions
@@ -1,9 +1,9 @@
-<p class="lead">You discovered CP-violation!</p>
+<p class="lead">You discovered CP violation!</p>

-<h4>CP Symmetry</h4>
-<p>C (Charge) and P (Parity) are discrete transformations that can be applied to a physical system.</p>
+<h5><b>CP Symmetry</b></h5>
+<p>C (Charge) and P (Parity, which can be thought of as “handedness”) are discrete transformations that can be applied to a physical system.</p>
 <p>If a theory is symmetric under C, then it works the same if all particles are exchanged with their antiparticles.
-If it has P-symmetry, then it is invariant under inversion ("mirroring") of all spatial coordinates</p>
+If it has P-symmetry, then it is invariant under inversion (“mirroring”) of all spatial coordinates.</p>

 <p>For a long time, physicists believed that all of physics is invariant under the combination CP of both symmetries.
 It turned out that this is wrong, as was discovered by Cronin, Fitch et al. in 1964 when they studied the decay of the neutral K meson.</p>
@@ -12,21 +12,21 @@ It turned out that this is wrong, as was discovered by Cronin, Fitch et al. in 1
 <div class="row">
    <h5>CPV in the Kaon System</h5>
    <div class="col-md-3">
-        <img class="img-responsive" src="assets/info/cpv.png" alt="A plot from the original publication">
+        <img class="img-responsive" src="../assets/info/cpv.png" alt="A plot from the original publication">
    </div>
    <div class="col-md-3">
        <p>In 1964, Cronin, Fitch, et al. showed that CP symmetry is broken in the decay of the long-lived neutral K meson.</p>
-        <p>If all of physics was invariant under CP transformation, then this long-lived version of the K meson would never decay into 2 pions.</p>
-        <p>Yet, this kind of decay was discovered!</p>
-        <p>You can see their results on the left: In the middle plot (the one relevant for K meson decays), a clear excess is recognizable.</p>
-        <p>For their discovery, Cronin and Fitch received the Nobel prize in 1980.</p>
+        <p>If all of physics was invariant under CP transformation, then this long-lived version of the K meson would never decay into two pions.</p>
+        <p>However, this kind of decay was discovered!</p>
+        <p>You can see their results on the left: In the middle plot (the one relevant for K-meson decays), a clear excess is recognizable.</p>
+        <p>For their discovery, Cronin and Fitch received the Nobel Prize in Physics in 1980.</p>
    </div>
 </div>

 <h5><b>Resources</b></h5>
 <ul>
  <li><a href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.13.138" target="_blank">The original publication by Cronin, Fitch et al.</a></li>
-  <li><a href="http://en.wikipedia.org/wiki/CP_violation" target=_blank">Wikipedia on CP violation</a></li>
+  <li><a href="http://en.wikipedia.org/wiki/CP_violation" target="_blank">Wikipedia on CP violation</a></li>
  <li><a href="http://en.wikipedia.org/wiki/Kaon#CP_violation_in_neutral_meson_oscillations" target="_blank">Neutral kaon mixing on Wikipedia</a></li>
 </ul>
 </div>
@@ -1,17 +1,18 @@
-<p class="lead">You discovered the J/ψ meson.</p>
+<p class="lead">You discovered the J/ψ meson!</p>
 <h5><b>The J/ψ meson</b></h5>
-<img class="img-responsive" src="assets/info/jpsi.png" alt="A plot from one of the original publications" align="center">
-<p>The J/ψ is a meson consisting of a charm quark and a charm antiquark. It is the first excited state of the charmonium (the bound state of a charm-anticharm state), that was discovered independently by two research groups in 1974: one at the Stanford Linear Accelerator Center, headed by Burton Richter, and one at the Brookhaven National Laboratory, headed by Samuel Ting of MIT. Richter and Ting were rewarded for their shared discovery with the 1976 Nobel Prize in Physics.
+<img class="img-responsive" src="../assets/info/jpsi.png" alt="A plot from one of the original publications" align="center">
+<p>
+The J/ψ is a meson consisting of a charm quark and its antiquark. It is the first excited state of the charmonium (a bound charm-anticharm state), and was discovered independently by two research groups in 1974: one at the Stanford Linear Accelerator Center, led by Burton Richter, and one at the Brookhaven National Laboratory, led by Samuel Ting of MIT. Richter and Ting were awarded the 1976 Nobel Prize in Physics for their shared discovery.
 </p>

 <h5><b>History of the name</b></h5>
 <p>
-Because of the nearly simultaneous discovery, the J/ψ is the only particle to have a two-letter name. Richter named it "SP", after the SPEAR accelerator used at SLAC; however, none of his coworkers liked that name. After consulting with Greek-born Leo Resvanis to see which Greek letters were still available, and rejecting "iota" because its name implies insignificance, Richter chose "ψ" – a name which, as Gerson Goldhaber pointed out, contains the original name "SP", but in reverse order.<br>Since the scientific community considered it unjust to give one of the two discoverers priority, most subsequent publications have referred to the particle as the "J/ψ"
+The J/ψ is the only particle with a two-letter name, as a result of its nearly simultaneous discovery by two independent groups. Ting wanted to name the particle “J”, while Richter called it “SP” (after the SPEAR accelerator used at SLAC), a name none of his colleagues liked. Richter finally settled on the Greek letter “ψ” (pronounced “psi”).<br>Since the scientific community considered it unjust to give one of the two discoverers priority, most subsequent publications have referred to the particle as the “J/ψ”.
 </p>

 <h5><b>Resources</b></h5>
 <ul>
  <li><a href="http://prl.aps.org/pdf/PRL/v33/i23/p1404_1" target="_blank">The original presentation of J. J. Aubert et al.</a></li>
  <li><a href="http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.33.1404" target="_blank">The original presentation of J.-E Augustin et al.</a></li>
-  <li><a href="http://en.wikipedia.org/wiki/J/psi_meson" target="_blank">J/psi meson on Wikipedia</a></li>
+  <li><a href="http://en.wikipedia.org/wiki/J/psi_meson" target="_blank">J/ψ meson on Wikipedia</a></li>
 </ul>
@@ -1,18 +1,19 @@
-<p class="lead">You discovered the bottom quark.</p>   
-   
-<h5><b>The bottom quark</b></h5>
-<img class="img-responsive" src="assets/info/b.png" alt="A plot from one of the original publications" align="center">
+<p class="lead">You discovered the bottom quark!</p>
+
+<h5><b>The bottom (or beauty) quark</b></h5>
+<img class="img-responsive" src="../assets/info/b.png" alt="A plot from one of the original publications" align="center">
 <br>
-<p>The bottom (or beauty) quark is a third-generation quark with a charge of -1/3. It has a large mass (around 4.2 GeV/c^2 — more that 4 times the proton mass!). The bottom quark is notable because it is a product in almost all top quark decays, and is a frequent decay product for the Higgs boson.
+<p>
+The bottom (or beauty) quark is a third-generation quark with a charge of &minus;&frac13;. It has a large mass (around 4.2 GeV/c<sup>2</sup> — more that four times the mass of a proton!). The bottom quark is notable because it is a product in almost all decays of the top quark and is a frequent decay product for the Higgs boson.
 </p>

 <h5><b>History of the discovery</b></h5>
 <p>
-The bottom quark was predicted in 1973 by physicists Makoto Kobayashi and Toshihide Maskawa as part of their explanation for CP violation. The name "bottom" was introduced in 1975 by Haim Harari. The bottom quark was discovered in 1977 by the Fermilab E288 experiment team led by Leon M. Lederman, when collisions produced bottomonium. Kobayashi and Maskawa won the 2008 Nobel Prize in Physics for their explanation of CP-violation. Upon its discovery, there were efforts to name the bottom quark "beauty", but "bottom" became the predominant name.
+The bottom quark was predicted in 1973 by physicists Makoto Kobayashi and Toshihide Maskawa as part of their explanation for CP violation. The name “bottom” was introduced in 1975 by Haim Harari. The bottom quark was discovered in 1977 by the Fermilab E288 experiment team led by Leon M. Lederman, when collisions produced bottomonia (mesons with a bottom quark and its antiquark). Kobayashi and Maskawa won the 2008 Nobel Prize in Physics for their explanation of CP violation. Upon its discovery, there were efforts to name the bottom quark “beauty”, but “bottom” became the predominant name.
 </p>

 <h5><b>Resources</b></h5>
 <ul>
  <li><a href="http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.39.252" target="_blank">The original presentation of S. W. Herb et al.</a></li>
  <li><a href="http://en.wikipedia.org/wiki/Bottom_quark" target="_blank">The bottom quark on Wikipedia</a></li>
-</ul> 
+</ul>
@@ -1,13 +1,11 @@
-<p class="lead">The description of the detector.</p>
-<h5><b>The particle detectors</b></h5>
-                                                                                                                                       
+<p class="lead">What are particle detectors?</p>
+
 <p>
-Particle detectors are high-tech devices used to study the interactions of composite and elementary particles.
-The detected particles can originate from nuclear decays, cosmic radiation or interactions in a particle accelerator.
-Modern detectors, such as those used at the LHC consist of many components, of which many are specialized to detect certain particles or certain particle properties.
+Particle detectors can be thought of as high-tech cameras that take “photographs” of phenomena that physicists want to study. These phenomena may originate in nuclear decays, cosmic radiation or interactions in a particle accelerator. Let us take a closer look at detectors such as those used at the LHC, which consist of layers of specialized components each designed to specific particles and identify certain properties.
 </p>

-<h5><b>Layers</b></h5>
+<h5><b>Components</b></h5>
+
 <h5><span class="badge" style="background:#FFF371;">&nbsp;</span>&nbsp;Tracker</h5>
 <p>
    The tracker helps us to calculate the momentum of charged particles. They bend due to magnetic field. The smaller the curve radius is, the less momentum the particle had. We also differentiate positive and negative particles based on the direction of the track.
@@ -20,7 +18,12 @@ Modern detectors, such as those used at the LHC consist of many components, of w

 <h5><span class="badge" style="background:#E1FF79;">&nbsp;</span>&nbsp;Hadronic calorimeter</h5>
 <p>
-    The Hadron Calorimeter (HCAL) is used to measure the energy of hadrons, particles made of quarks and gluons. Some examples of them are protons, neutrons and pions. It also helps us detect neutrinos but indirectly. Energy needs to be conserved, so if we observe missing energy, this indicates neutrinos.
+    The Hadron Calorimeter (HCAL) is used to measure the energy of hadrons, composite particles that made of quarks and gluons. Some examples of hadrons are protons, neutrons and pions. It also helps us detect neutrinos but indirectly. Energy needs to be conserved, so if we observe missing enery, this indicates neutrinos or as-yet-undiscovered particles flew through the detector.
+</p>
+
+<h5><span class="badge" style="background:#A0B3FF;">&nbsp;</span>&nbsp;Magnet</h5>
+<p>
+    Particle detectors require magnets with very strong magnetic fields in order to sufficiently bend particles flying with high momenta. Trajectories of particles with higher momenta bend less, while those with lower momenta bend a lot more. The magnetic field also helps distinguish between positively and negatively charged particles: they bend in opposite directions in the same magnetic field.
 </p>

 <h5><span class="badge" style="background:#EA301F;">&nbsp;</span>&nbsp;Muon chamber</h5>
@@ -32,4 +35,4 @@ Modern detectors, such as those used at the LHC consist of many components, of w
 <ul>
  <li><a href="http://en.wikipedia.org/wiki/Particle_detector" target="_blank">Particle detectors on Wikipedia</a></li>
  <li><a href="http://en.wikipedia.org/wiki/Compact_Muon_Solenoid" target="_blank">The CMS detector on Wikipedia</a></li>
-</ul> 
+</ul>
@@ -1,17 +1,18 @@
-<p class="lead">You discovered the Tau lepton.</p>
-<h5><b>The tau lepton</b></h5>
-<img class="img-responsive" src="assets/info/tau.png" alt="A plot from the original publication" align="right">
-The tau is an elementary particle similar to the electron, with negative electric charge and a spin of 1/2. Together with the electron, the muon, and the three neutrinos, it is classified as a lepton. Despite of the meaning of the word lepton (fine, small, thin) the tau is very massive: it has mass of 1776.82 MeV/c^2 (for comparison: the mass of the electron is 0.511 MeV/c^2, the mass of the proton is 938.27 MeV/c^2).
-<p></p>
-
-<h5><b>The discovery of the tau</b></h5>
+<p class="lead">You discovered the τ lepton!</p>
+<h5><b>The τ lepton</b></h5>
+<img class="img-responsive" src="../assets/info/tau.png" alt="A plot from the original publication" align="right">
 <p>
-The tau was detected in a series of experiments between 1974 and 1977 by Martin Lewis Perl with his colleagues at the SLAC-LBL group. Their equipment consisted of SLAC's then-new e+–e− colliding ring, called SPEAR, and the LBL magnetic detector. They could detect and distinguish between leptons, hadrons and photons.<br>
+The τ (tau) is an elementary particle that can be thought of as a much heavier cousin of the electron, with a spin of &frac12;. It belongs to the family of leptons, along with the electron, the muon, and the three neutrinos. Despite the origin of the word lepton (meaning fine, small, thin) the τ is very massive at 1776.82 MeV/c<sup>2</sup>, which is nearly 3500 times the mass of the electron and around twice the mass of the proton.
+</p>
+
+<h5><b>The discovery of the τ</b></h5>
+<p>
+The τ was detected in a series of experiments between 1974 and 1977 by Martin Lewis Perl and his colleagues at the SLAC-LBL group. Their equipment consisted of SLAC’s then-new e<sup>+</sup>e<sup>&minus;</sup> colliding ring, called SPEAR, and the LBL magnetic detector. They could detect and distinguish between leptons, hadrons and photons.<br>
 Martin Perl shared the 1995 Nobel Prize in Physics with Frederick Reines. The latter was awarded his share of the prize for experimental discovery of the neutrino.
 </p>

 <h5><b>Resources</b></h5>
 <ul>
-  <li><a href="http://en.wikipedia.org/wiki/Tau_(particle)" target="_blank">The Tau lepton on Wikipedia.</a></li>
  <li><a href="http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.35.1489" target="_blank">The original publication by M. L. Perl et al.</a></li>
-</ul>   
+  <li><a href="http://en.wikipedia.org/wiki/Tau_(particle)" target="_blank">The τ lepton on Wikipedia.</a></li>
+</ul>
@@ -1,16 +1,17 @@
-<p class="lead">You discovered the top quark.</p>
+<p class="lead">You discovered the top quark!</p>
 <h5><b>The top quark</b></h5>
-<img class="img-responsive" src="assets/info/t.png" alt="A plot from one of the original publications" align="center">                                                                                                                                       
+<img class="img-responsive" src="../assets/info/t.png" alt="A proton and an antiproton annhilate to form a top-antitop pair" align="center">
+
 <p>
-More information will come here...
+At 174.2 GeV/c<sup>2</sup>, the top quark is the heaviest particle we know of. It belongs to the third generation of quarks and has a charge of &frac23;. As a result of its large mass, it decays (mostly into bottom quarks) almost instantly after it is produced. This behemoth does not form bound states with other quarks or antiquarks.
 </p>

-<h5><b>History</b></h5>
+<h5><b>History of the top quark</b></h5>
 <p>
-...and also here.
+Coming soon…
 </p>

 <h5><b>Resources</b></h5>
 <ul>
  <li><a href="http://en.wikipedia.org/wiki/Top_quark" target="_blank">The top quark on Wikipedia</a></li>
-</ul> 
+</ul>
@@ -1,11 +1,19 @@
-<p class="lead">You discovered the W and Z bosons.</p>
+<p class="lead">You discovered the W and Z bosons!</p>
 <h5><b>The weak force</b></h5>
-<img class="img-responsive" src="assets/info/antihydrogen.png" alt="A plot from one of the original publications" align="center">                                                                                                                                       
+<img class="img-responsive" src="../assets/info/w.png" alt="A W&minus; boson produced in the transformation of a neutron into a proton" align="center">
 <p>
-More information will come soon...
+The weak interaction is a nuclear process that is responsible, among other things, for &beta; (beta) decay the transformation of neutrons into protons. The weak force is mediated by two bosons called the W and the Z. The W comes in two types: W<sup>+</sup> and W</sup>&minus;</sup>. The Z is neutral and is sometimes represented as Z<sup>0</sup>.
+</p>
+
+<h5><b>Discovery of the W and Z bosons</b></h5>
+
+<p>
+The W and Z bosons are quite massive and so require powerful accelerators in order to be produced and studied. The Super Proton Synchrotron at CERN was the first machine capable of this, and the UA1 collaboration lead by Carlo Rubbia discovered both particles in 1983. Rubbia along with Simon Van der Meer, whose developments on the accelerator allowed such a machine to be built, were jointly awarded the Nobel Prize in Physics in 1984.
 </p>

 <h5><b>Resources</b></h5>
 <ul>
+  <li><a href="http://cds.cern.ch/record/854078/" target="_blank">CERN Press Release announcing the discovery of the W boson</a></li>
  <li><a href="http://en.wikipedia.org/wiki/Weak_interaction" target="_blank">The weak interaction on Wikipedia</a></li>
-</ul> 
+  <li><a href="http://en.wikipedia.org/wiki/W_and_Z_bosons" target="_blank">The W and Z bosons on Wikipedia</a></li>
+</ul>