Carnival of the Subatomic Particles

Carnival of the

Elementary

Particles

PROLOGUE

I. Everything is made of Atoms

Democritus, an ancient Greek

Philosopher, once tried to seek

The answer to a vexing riddle:

Break a stick right down the middle,

Giving you two little sticks.

Now, if you enjoy such tricks,

Then repeat the whole procedure

With one small stick. You may need your

Sharpest knife to make the slice,

But now you will have done it twice!

Will the process never cease?

Or must there be a smallest piece

Which can't be cut up into pieces,

At which point the cutting ceases?

Atoms are that smallest part,

Beyond which point the cutter's art

No longer functions. So taught us

That ancient Greek: Democritus.

II. But there are things inside Atoms

But I have always found it risible

To call the Atom indivisible,

When deep inside all Atoms lie

Their very tiny Nuclei,

Containing almost all the mass,

Surrounded by a foggy gas:

Electrons! We should all be proud

How much we know about that cloud,

Whose properties were once a mystery

But now belong to science history:

An explanation full and blemish-free

That underlies the whole of chemistry.

III. And things inside the Nucleus

And yet the story's even richer.

Within the Nucleus we picture

Nucleons: still smaller particles,

About which I could write whole articles.

But let it here suffice to say

The two varieties that they

Possess. (1) Protons with a charge

Of electricity just large

Enough to hold Electrons in

Those clouds in which they whirl and spin.

(2) Neutrons: uncharged partners of

The Protons, held to them as love

Binds lovers in their warm embrace,

But bound by Mesons in this case.

What could be to God's greater glory?

And yet there's much more to the story!

IV. And things inside the Nucleons!

The Nucleons themselves have pieces

Described in many a doctor's thesis.

The Standard Model is the name

Of this subnucleonic game.

It underlies the interplay

Of everything. And so, I say:

Enough of idle talk and twaddle:

Let's celebrate the Standard Model!

THE STANDARD MODEL

The Up and Down Quarks are the units

That make both Nucleons behave

In just the manner that they do. It's

Extremely simple. Note that they've

Both got inside them smaller pieces.

For Nucleons are like valises,

Each stuffed with Quarks. We now agree

A Nucleon is made of three

Internal Quarks. Quite elementary:

The Protons are two Ups, one Down

All bound together like a crown;

In Nature’s book another entry:

The Neutrons are two Downs, one Up,

Together, in a single cup.

The Protons all have just one unit

Of charge, electrical. Although

The Neutrons lack charge -- yes they do! (It

Permits them easily to flow

Through crystals.) But this neat arrangement

Requires some genuine estrangement

From common notions. Thus, the charge

Of Up Quarks isn't very large:

Only two-thirds the normal portion

That one expects a charge to be.

What's more, the Down Quark, cunningly,

Has just one-third. And here's a caution:

Up and Down charges, that combine,

Are furnished with a different sign.

So Up-Down-Down has full charge zero

While Up-Up-Down has full charge one.

It doesn't take a super hero

To realize the job's now done.

The tripling has been quite delightful:

The Proton’s charge is just its rightful

Amount. The other way Quarks fall

The Neutron gets no charge at all.

Next you may ask what is the tether

That holds these trios in one place?

Instead of wandering through space

What makes three Quarks remain together?

The Gluons! Gluons do the job

Of making Quarks a single blob.

The way in which the Gluons tie in

A group of Quarks to just one place

Deserves a mention very high in

Examples of a strong embrace.

For if you try to tear asunder

Three Quarks you make a real blunder:

You'll find the harder that you try,

The stronger bond the Gluons tie.

For Gluons bear the strict assignment

Not to let single Quarks appear.

I have to make that very clear.

This property is called Confinement.

However much you try to free

A single Quark, it cannot be.

Each Nucleon's a three-Quark triple

One Up, two Downs; Two Ups, one Down.

But there's another little stipul-

Ation that has acquired renown:

For you should know that Quarks have color,

Although to make the story duller,

It's not the kind that you can see

But just a form of poetry.

The colors don’t come in profusion.

One Quark is Red, one Green, one Blue.

That's all there is. I'm telling you

To ward off possible confusion.

And here's a final piece of news:

The anti-Quarks have anti-hues.

The anti-Red-Quark, for example,

Has to be colored anti-Red.

Likewise, I'm sure it wouldn't trample

The preconceptions in your head

To learn the hue of anti-Blue-Quarks

Is anti-Blue. And like all true Quarks

The anti-Green-Quark has to mean

A Quark that's colored anti-Green.

Now here's a rule that's quite delicious:

The Red and Green and Blue make White.

The color's disappeared, alright.

And though it may not sound propitious

When color, anti-color play

All of the color goes away.

All particles are colored purely

Neutral if they're directly seen.

In Nucleons the three Quarks surely

Must then be Red, and Blue, and Green.

Another way that's somewhat duller

To make up something lacking color

Directly puts together two

Paired Quarks of hue and anti-hue.

In just this way one makes a Meson,

Like Pion, Eta, Kaon, Rho

And others ones you might not know

Unless you have a special reason.

Only the parts have color. Yes,

The things we see are colorless.

Now Up and Down are not the only

Varieties that Quarks possess.

In case you worried they'd be lonely,

You needn't fear. For I confess

There are two other generations

That furnish Quarkish explanations

Of why there is so big a zoo.

Each generation comes with two

Fine Quarkish partners. One pair's Charméd

And Strange. The other's Bottom, Top.

This makes you wonder, will it stop?

No problem. Do not be alarméd!

There's nothing else we have to fix.

The Quarkish flavors stop at six.

You may remember that I've spoken

About Electrons, tiny things.

They too have partners (I'm not jokin'!)

That fly about as though on wings.

Neutrinos have the smallest masses

Of all the fundamental classes

Of particles. As I recall.

They've hardly any mass at all.

Through endless ranks of rocks and boulder

At speeds approaching that of light

They pass unhindered in their flight.

There's almost nothing that can shoulder

Those swift Neutrinos off their path.

We live in a Neutrino bath!

Here too things come in generations.

A heavy 'lectron called the Mu

Is one of God's more strange creations.

And has its own Neutrino, too.

A third Neutrino fills the picture.

Following a familiar stricture,

Which surely isn't broken now,

Its partner's the still heavier Tau.

Electron, Mu, and Tau along with

All their Neutrinos, commonly

Are known as Leptons. These make three

New generations that belong with

The three Quark pairs. The same format!

Well might one ask “Who ordered that?"

A flavor changing transmutation

Is called a weak decay. And there's

Accompanying it the swift creation

Of Lepton-Antilepton pairs.

The Down- to Up-Quark weak transition

-- Beta decay (from old tradition) --

Creates Electrons, moving fast,

And Antineutrinos in the blast.

This is the way that Neutrons trouble you,

Turning to Protons with the aid

Of two assistants, that are made

Of new gauge fields. Called Z and W

They're massive cousins to a sprite:

The massless Photon, speck of light.

Behold the Higgs! The most elusive

Of particles, I do insist.

Not yet observed, we lack conclusive

Data to show that they exist.

Without the Higgs there'd be no masses

Creating some grotesque impasses.

This means within our Standard tale

The Higgs's the crucial Holy Grail.

Please do not doubt the Higgs' reality.

We're hoping very soon to learn

From evidence produced at CERN

That it exists, with clear finality.

So don't forget: the Higgs's the thing

That makes the Standard Model King.

EPILOGUE: THE HYDROGEN ATOM

Democritus had not a notion

Of Hydrogen in ancient Greece,

Much less an inkling of the motion

Within its Atom, without cease.

But we, today, know that there's really

A swift Electron, moving freely

Around three Quarks, of different hue

All bound by Gluons' cosmic glue.

If you were ever once afraid of

Not understanding Nature's ways,

Here it unfolds, beneath your gaze.

These are such stuff as dreams are made of.

See how the Quarks and Gluons prance!

Behold their magic as they dance!