کوارکها

کوارکها ذرات بنیادی ماده هستند که نوترون، پروتون و سایر هادرونها را تولید می کنند. شش نوع کوارک مختلف وجود دارد که هر کدام از آنها طعم نامیده می شوند.

طعم		جرم  (GeV/c2)	بار الکتریکی (e)
u بالا	up	0.004	+2/3
d پائین	down	0.008	-1/3
c افسون	charm	1.5	+2/3
s  عجیب	strange	0.15	-1/3
t سر	top	176	+2/3
b ته	bottom	4.7	-1/3

کوارکها فقط درون هادرونها وجود دارند. زیرا بوسیله میدان نیروی کنش قوی (بار -رنگی) محدود شده اند. بنابراین نمی توانیم با منزوی کردن کوارکها جرم آنها را اندازه گیری کنیم. بعلاوه جرم هادرونها از از مجموع انرژی جنبشی و انرژی پتانسیل در حین کنش قوی به دست می آید.

هادرونهایی که از کوارکهای سبک ساخته می شوند، مجموع جرم کوارکهای تشکیل دهنده ی هادرون، بیشتر از جرم هادرون است. برای مثال جرم پروتون را با مجموع جرم دو کوارک بالا و یک کوارک پائین (که اجزاء سازنده ی پروتون هستند) مقایسه کنید.

up+	up+	down	=	proton
0.004	0.004	0.008		0.938

بنابراین سئوال این است که منظور ما از جرم کوارک چیست و چگونه آن را اندازه می گیریم؟ کمیتی را که که ما بعنوان جرم کوارک مطرح می کنیم، در حقیقت از رابطه ی زیر تعریف می شود:

F = ma,  m=F/a

این معادله بما می گوید، یک جسم در مقابل اعمال نیرو بر آن چگونه رفتار می کند. معادلات فیزیک ذرات بنیادی حاوی روش محاسبه این است که هنگام برخورد یک فوتون پر انرژی با کاروک چه اتفاقی روی می دهد. جرم کوارک عامل کنترل شتاب آن در مقابل نیروی اعمال شده بر کوارک است. این روش تابت و بهترین راه همآهنگی نظریه و آزمایش است تا هم نسبت جرم انواع هادرونها مطالعه کنیم و هم رفتار کوارکها را در آزمایشهایی با انرژی بالا.  در هر صورت، با هیچ یک از این روشها نمی توان جرم دقیق کوارکها را تعیین کرد.

 

چگونه می دانیم که کوارکها واقعی هستند؟

 

 سئوالی که ممکن است مطرح شود این است که اگر ما نمی توانیم کوارکها را از هم جدا کنیم، چگونه می دانیم که آنها در ساختمان هادرونها وجود دارند؟ پاسخ ساده است، تمام محاسبات ما بر وجود آنها تاکید دارد و نتیجه ی آزمایشها جواب درستی می دهد.

For example, when we bounce electrons off of protons and neutrons, the pattern of scattering angles observed is characteristic of point-like spin-1/2 scatters. The relative rates for electron versus neutrino scattering is that predicted from the quark electric charges. The process of electron-positron annihilation to quark pairs gives similar characteristic predictions, all these are also confirmed experimentally. The accumulation of many such results, where experiments match predictions based on quarks, convinces us that quarks are real.

 

quark properties

May we proudly present the players of the leading parts on the stage of the micro-cosmos? They will presently perform: "the nuclear interactions". Here they come...............

The quarks:

down charge = -1/3 spin = +1/2 mass = 3-9 MeV

up charge = +2/3 spin = +1/2 mass = 1-5 MeV

The "charge" is equal to the distance from the center of gravity of the triangle to the horizontal axis. The value of the "spin" equals the surface of the triangle (= 1/2). The direction of the spin is the direction whereto the triangle points, clockwise is positive. The "color-property" is represented by the colors. The colors of the quarks are randomly chosen here. The "mass" is not represented in the pictoquarks.

Mirrored round the vertical axis, the quarks have negative spin:

down charge = -1/3 spin = -1/2 mass = 3-9 MeV

up charge = +2/3 spin = -1/2 mass = 1-5 MeV

Mirrored round the horizontal axis we see the "anti-quarks":

anti-down charge = +1/3 spin = +1/2 mass = 3-9 MeV

anti-up charge = -2/3 spin = +1/2 mass = 1-5 MeV

The next 4 quarks have the same properties as the down and the up, but with greater mass:

strange charge = -1/3 spin = +1/2 mass = 75-170 MeV

charm charge = +2/3 spin = +1/2 mass = 1150-1350 MeV

bottom charge = -1/3 spin = +1/2 mass = 4000-4400 MeV

top charge = +2/3 spin = +1/2 mass = 175000 MeV

Anti-strange, anti-charm, anti-bottom and anti-top are mirrored round the horizontal axis.

Stability.

Down, up, anti-down and anti-up are stable quarks; the other quarks have too much mass and are unstable. After a very short time the unstable quarks loose this extra mass and automatically decay into lighter quarks.

Here are pictoquarks of all 24 quarks together, with these pictures and pictures of the neutrinos you can visualize all matter and anti-matter in the universe.

stable

unstable

plural unstable

Colors.

The quarks are not colored at all but they posses a property that acts like a color. The colors in the pictoquarks are symbolic and represent this property. All elementary particles are white and you can visualize them as combinations of 3 quarks, 3 anti-quarks or quark/anti-quark pairs, sometimes with a neutrino. Particles that would exist out of more than 3 quarks are left out of consideration. Quarks are red, green or blue and anti-quarks have the anti-colors: cyan, magenta or yellow.

• red, green, and blue - (3 quarks)
• cyan, magenta, and yellow - (3 anti-quarks)
• red, and cyan - (quark + anti-quark)
• green, and magenta - (quark + anti-quark)
• blue, and yellow - (quark + anti-quark)

Adding and subtracting of pictoquarks.

Pictoquarks can be added together to form particles that consist of several quarks. To illustrate the addition of pictoquarks, the proton and the neutron are composed here.

+

+

=

+

+

=

Together with the pictoquarks you add the charge, the spin and the colors. The sum of the masses is more than the masses of the quarks in all; this problem still needs to be solved.

Subtracting a quark is the same as adding an anti-quark.

http://home.hetnet.nl/

Quarks are fundamental matter particles that are constituents of neutrons and protons and other hadrons. There are six different types of quarks. Each quark type is called a flavor.

Flavor		Mass (GeV/c2)	Electric Charge (e)
u	up	0.004	+2/3
d	down	0.008	-1/3
c	charm	1.5	+2/3
s	strange	0.15	-1/3
t	top	176	+2/3
b	bottom	4.7	-1/3

Quarks only exist inside hadrons because they are confined by the strong (or color charge) force fields. Therefore, we cannot measure their mass by isolating them. Furthermore, the mass of a hadron gets contributions from quark kinetic energy and from potential energy due to strong interactions. For hadrons made of the light quark types, the quark mass is a small contribution to the total hadron mass. For example, compare the mass of a proton (0.938 GeV/c²) to the sum of the masses of two up quarks and one down quark (total of 0.02 GeV/c²).

So the question is, what do we mean by the mass of a quark and how do we measure it. The quantity we call quark mass is actually related to the m in F = ma (force = mass x acceleration). This equation tells us how an object  will behave when a  force is applied. The equations of particle physics include, for example, calculations of what happens to a quark when struck by a high energy photon.  The parameter we call quark mass controls its acceleration when a force is applied. It is fixed to give the best match between theory and experiment both for the ratio of masses of various hadrons and for the behavior of quarks in high energy experiments. However, neither of these methods can precisely determine quark masses.  

 

How Do We Know Quarks Are Real?

A question you might well ask!  If we cannot separate them out, how do we know they are there? The answer is simply that all our calculations depend on their existence and give the right answers for the experiments.

For example, when we bounce electrons off of protons and neutrons, the pattern of scattering angles observed is characteristic of point-like spin-1/2 scatters. The relative rates for electron versus neutrino scattering is that predicted from the quark electric charges. The process of electron-positron annihilation to quark pairs gives similar characteristic predictions, all these are also confirmed experimentally. The accumulation of many such results, where experiments match predictions based on quarks, convinces us that quarks are real.

 

quark properties

May we proudly present the players of the leading parts on the stage of the micro-cosmos? They will presently perform: "the nuclear interactions". Here they come...............

The quarks:

down charge = -1/3 spin = +1/2 mass = 3-9 MeV

up charge = +2/3 spin = +1/2 mass = 1-5 MeV

The "charge" is equal to the distance from the center of gravity of the triangle to the horizontal axis. The value of the "spin" equals the surface of the triangle (= 1/2). The direction of the spin is the direction whereto the triangle points, clockwise is positive. The "color-property" is represented by the colors. The colors of the quarks are randomly chosen here. The "mass" is not represented in the pictoquarks.

Mirrored round the vertical axis, the quarks have negative spin:

down charge = -1/3 spin = -1/2 mass = 3-9 MeV

up charge = +2/3 spin = -1/2 mass = 1-5 MeV

Mirrored round the horizontal axis we see the "anti-quarks":

anti-down charge = +1/3 spin = +1/2 mass = 3-9 MeV

anti-up charge = -2/3 spin = +1/2 mass = 1-5 MeV

The next 4 quarks have the same properties as the down and the up, but with greater mass:

strange charge = -1/3 spin = +1/2 mass = 75-170 MeV

charm charge = +2/3 spin = +1/2 mass = 1150-1350 MeV

bottom charge = -1/3 spin = +1/2 mass = 4000-4400 MeV

top charge = +2/3 spin = +1/2 mass = 175000 MeV

Anti-strange, anti-charm, anti-bottom and anti-top are mirrored round the horizontal axis.

Stability.

Down, up, anti-down and anti-up are stable quarks; the other quarks have too much mass and are unstable. After a very short time the unstable quarks loose this extra mass and automatically decay into lighter quarks.

Here are pictoquarks of all 24 quarks together, with these pictures and pictures of the neutrinos you can visualize all matter and anti-matter in the universe.

stable

unstable

plural unstable

Colors.

The quarks are not colored at all but they posses a property that acts like a color. The colors in the pictoquarks are symbolic and represent this property. All elementary particles are white and you can visualize them as combinations of 3 quarks, 3 anti-quarks or quark/anti-quark pairs, sometimes with a neutrino. Particles that would exist out of more than 3 quarks are left out of consideration. Quarks are red, green or blue and anti-quarks have the anti-colors: cyan, magenta or yellow.

• red, green, and blue - (3 quarks)
• cyan, magenta, and yellow - (3 anti-quarks)
• red, and cyan - (quark + anti-quark)
• green, and magenta - (quark + anti-quark)
• blue, and yellow - (quark + anti-quark)

Adding and subtracting of pictoquarks.

Pictoquarks can be added together to form particles that consist of several quarks. To illustrate the addition of pictoquarks, the proton and the neutron are composed here.

+

+

=

+

+

=

Together with the pictoquarks you add the charge, the spin and the colors. The sum of the masses is more than the masses of the quarks in all; this problem still needs to be solved.

Subtracting a quark is the same as adding an anti-quark.

http://home.hetnet.nl/