• Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, worn by a woman
  • Corekeeper worn on a model – Pixelated Physics
  • White Corekeeper physics T-shirt, pixel-art strong nuclear force design, worn by a man
  • White Corekeeper physics T-shirt, pixel-art strong nuclear force design, front view
  • Pixelated Physics neck label inside the white Corekeeper physics T-shirt
  • White Corekeeper physics T-shirt, pixel-art strong nuclear force design, folded
  • White Corekeeper physics T-shirt, pixel-art strong nuclear force design, hanging on a chair
  • White Corekeeper physics T-shirt, plain back view
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, worn by a man
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, front view
  • Black Corekeeper physics T-shirt, plain back view
  • Pixelated Physics neck label inside the black Corekeeper physics T-shirt
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, folded
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, front view
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, worn by a man
  • Size chart for the Corekeeper unisex strong nuclear force physics T-shirt
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, hanging on a chair
  • Black Corekeeper physics T-shirt, pixel-art strong nuclear force design, on a hanger
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CorekeeperStrong Nuclear Force / Nuclear Binding

Corekeeper – Strong Nuclear Force / Nuclear Binding Physics T-Shirt

$29.99 USD
$29.99 USD
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Shipping calculated at checkout. Free US shipping · $10 flat shipping outside the US.
Color
White · Black
Size
S–5XL
Made
To order · shipping times

Every nucleus heavier than hydrogen packs protons that repel each other, yet it holds together. The strong force binds protons and neutrons in every nucleus, overcoming proton repulsion at femtometre range. Corekeeper wears it in pixel art on a unisex tee. The physics panel below has the equation, every symbol and the sources.

Color
Size

Size guideS–5XL · inches

Free US shipping$10 flat shipping outside the USMade to order, ships in 2–5 business days

Details

Size & fitS–5XL

Unisex heavy cotton (Gildan 5000), classic fit.

SizeWidthLengthSleeve
S182815.1
M202916.5
L223018
XL243119.5
2XL263221
3XL283322.4
4XL303423.7
5XL323525

Measurements in inches, ±1.5 in tolerance.

ShippingFree US

Free US shipping · $10 flat shipping outside the US. Printed to order for you.

Delivery times & where we ship

Returns & replacements21 days

Every item is printed to order, so we can’t accept returns or exchanges for change of mind, or if you ordered the wrong size or colour.

Print defect, misprint, damage or the wrong item? We’ll send a free replacement, or a refund if you prefer. Report it within 21 days of delivery with a photo; no need to send it back.

Full refund & replacement policy

The physics

Corekeeper holds on hard, but only up close. Step back a couple of femtometres and he lets go.

Inside a nucleus, protons repel one another electrically. In 1935 Hideki Yukawa proposed that nucleons hold each other by trading a particle, and saw that the mass of that particle would set the reach of the force. A briefly borrowed particle of mass m cannot travel far before it must be paid back, about ħ/mc. Make the reach the size of a nucleus and the carrier should weigh a couple of hundred electron masses. That is the first formula on this page: an attraction that dies away exponentially beyond the range λ.

The particle turned up in 1947 in photographic emulsions exposed to cosmic rays, and was named the pion. Cecil Powell received the 1950 Nobel Prize for the photographic method and its meson discoveries; Yukawa had received the 1949 prize for the prediction. Put the measured charged-pion mass, 139.57 MeV, into Yukawa's range and you get 1.41 femtometres, about the spacing of nucleons in a nucleus. Today this pull is understood as a residue of the strong force between quarks, much as the forces between neutral molecules are residues of the electric forces inside them.

The second formula measures how tightly he holds. Weigh a helium-4 nucleus and it comes up short. Two protons and two neutrons, weighed separately, total 28.3 MeV more than the nucleus they form: about 0.75 percent of the mass, missing. That missing mass is the binding energy, released when the nucleus was made, and the energy needed to pull it apart. Building helium from hydrogen releases energy on this scale, which is why it powers the Sun.

Corekeeper does not chase anyone. His grip is fierce at one femtometre and nearly gone at five.

Equations

\[V(r) = -\frac{g^{2}}{4\pi}\frac{e^{-r/\lambda}}{r}, \qquad \lambda = \frac{\hbar}{m_\pi c}\]
\[B = \left(Z m_p + N m_n - M_{\text{nuc}}\right)c^{2}\]
SymbolMeaningUnit
\(V(r)\) Yukawa potential between nucleons \(\mathrm{J}\)
\(g\) coupling constant (Gaussian-like units: g²/r has units of energy) \(\mathrm{J^{1/2}·m^{1/2}}\)
\(\lambda\) range of the force \(\mathrm{m}\)
\(m_\pi\) pion mass \(\mathrm{kg}\)
\(B\) nuclear binding energy (quoted in MeV) \(\mathrm{J}\)
\(Z, N\) proton and neutron numbers \(\mathrm{1}\)
\(m_p, m_n\) proton, neutron masses \(\mathrm{kg}\)
\(M_{\text{nuc}}\) nuclear mass \(\mathrm{kg}\)

Sources

  1. NobelPrize.org — Hideki Yukawa, Physics 1949, facts
  2. Encyclopaedia Britannica — Strong force
  3. NIST CODATA 2022 — proton mass energy equivalent in MeV
  4. NIST CODATA 2022 — neutron mass energy equivalent in MeV
  5. NobelPrize.org — Cecil Powell, Physics 1950, facts
  6. PDG 2024 listings — charged pion (mass 139.57039 MeV)
  7. NIST CODATA 2022 — reduced Planck constant times c in MeV fm
  8. NIST CODATA 2022 — alpha particle mass energy equivalent in MeV
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Field notes

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