Detailed slide-by-slide text content extracted from this presentation.
Slide 01
Particle Physics
- The Standard Model and the Fundamental Building Blocks of the Universe
- QUARKSLEPTONSBOSONSHIGGSQCD
Slide 02
The Standard Model
- The Standard Model of particle physics is our most successful description of fundamental matter and forces. It classifies all known elementary particles and describes three of the four fundamental interactions.
- Matter Particles (Fermions)
- Spin-1/2 particles that make up all visible matter. 6 quarks and 6 leptons, arranged in three generations of increasing mass.
- Force Carriers (Bosons)
- Spin-1 particles that mediate interactions. Photon (electromagnetic), W/Z (weak), 8 gluons (strong). Plus the spin-0 Higgs boson.
- What's Missing
- Gravity (no quantum description), dark matter, dark energy, neutrino masses (require extension), matter-antimatter asymmetry, and the hierarchy problem.
Slide 03
Quarks
- Six flavors of quarks combine in groups of two (mesons) or three (baryons) to form all hadrons. Never observed in isolation due to color confinement.
- The Six Quarks
- Up (u): charge +2/3, mass ~2 MeV. Lightest quark.
- Down (d): charge -1/3, mass ~5 MeV
- Charm (c): charge +2/3, mass ~1.3 GeV
- Strange (s): charge -1/3, mass ~100 MeV
- Top (t): charge +2/3, mass ~173 GeV. Heaviest fermion.
- Bottom (b): charge -1/3, mass ~4.2 GeV
- Color Charge
- Quarks carry "color" charge (red, green, blue) -- the source of the strong force. Only color-neutral combinations are observed: RGB (baryons) or color-anticolor (mesons). This confinement mechanism means pulling quarks apart creates new quark pairs from the energy input.
- Proton = uud (charge +1)
- Neutron = udd (charge 0)
Slide 04
Leptons
- Six leptons that do not feel the strong force. Three charged (electron, muon, tau) and three neutral (neutrinos). Each generation is heavier than the previous.
- Electron (e)
- Mass: 0.511 MeV. Stable. Orbits nuclei to form atoms. Responsible for all of chemistry, electricity, and solid-state physics. Discovered 1897 (J.J. Thomson).
- Muon (mu)
- Mass: 106 MeV (207x electron). Lifetime: 2.2 microseconds. "Who ordered that?" -- I.I. Rabi. Muon g-2 anomaly may hint at new physics.
- Tau (tau)
- Mass: 1777 MeV. Lifetime: 2.9 x 10^-13 s. Heavy enough to decay into hadrons. Discovered 1975 (Martin Perl, Nobel 1995).
- Neutrinos
- Three flavors (electron, muon, tau). Extremely light (
Slide 05
The Four Fundamental Forces
- Strong Nuclear
- Binds quarks into hadrons and protons/neutrons into nuclei. Mediated by 8 gluons. Range: ~10^-15 m. Strongest force but short-range due to gluon self-interaction. Described by QCD.
- Electromagnetic
- Acts between charged particles. Mediated by photons. Infinite range (1/r^2). Responsible for light, chemistry, electronics. Described by QED -- most precisely tested theory in physics.
- Weak Nuclear
- Responsible for radioactive beta decay and neutrino interactions. Mediated by massive W+, W-, Z bosons. Very short range (~10^-18 m). Allows quark flavor changes.
- Gravity
- Universal attraction between masses. Hypothetical mediator: graviton (spin-2, massless). Infinite range but incredibly weak (10^-38 x strong force). Not included in Standard Model. Described by General Relativity.
Slide 06
The Higgs Mechanism
- "I think we have it."CERN Director-General Rolf Heuer, July 4, 2012
- The Higgs field permeates all of space. Particles that interact with it acquire mass; those that don't (photons, gluons) remain massless. The Higgs boson is the quantum excitation of this field.
- Electroweak Symmetry Breaking
- At high temperatures the weak and EM forces are unified. As the universe cooled, the Higgs field acquired a non-zero vacuum value, breaking this symmetry and giving W/Z bosons their mass.
- Discovery at the LHC
- July 4, 2012: ATLAS and CMS independently confirmed a 125 GeV boson consistent with the Higgs. Required 40 years of theoretical prediction, $9 billion accelerator, and analysis of trillions of collisions.
- Properties
- Mass: 125.25 GeV. Spin: 0 (only fundamental scalar). Decays to: bb, WW, ZZ, tau-tau, gamma-gamma. Lifetime: ~10^-22 s. Yukawa couplings proportional to fermion masses.
Slide 07
Quantum Chromodynamics (QCD)
- The theory of the strong interaction between quarks and gluons. Unlike QED, gluons themselves carry color charge, leading to remarkable phenomena.
- Key Properties
- Confinement: Quarks cannot be isolated; energy grows with separation until new pairs form
- Asymptotic freedom: At high energies, quarks become nearly free (Nobel 2004: Gross, Politzer, Wilczek)
- Gluon self-coupling: 8 gluons interact with each other (unlike photons)
- Color neutrality: Only colorless bound states (hadrons) exist
- Phenomena
- Jet formation in colliders (quarks hadronize)
- Quark-gluon plasma at RHIC and LHC (deconfined matter)
- Proton mass: ~99% from gluon field energy, not quark masses
- Lattice QCD: numerical solution on discrete spacetime grids
Slide 08
Electroweak Unification
- Glashow, Weinberg, and Salam showed that electromagnetism and the weak force are manifestations of a single electroweak interaction, unified above ~100 GeV. Nobel Prize 1979.
- Gauge Symmetry: SU(2) x U(1)
- The electroweak theory is based on local gauge invariance under SU(2)_L x U(1)_Y. Four gauge bosons: W1, W2, W3, and B. After symmetry breaking, these mix into W+, W-, Z, and the photon.
- Parity Violation
- The weak force violates parity (mirror symmetry) maximally: it couples only to left-handed fermions and right-handed antifermions. Wu experiment (1957) confirmed this shocking prediction.
- Neutral Currents
- The Z boson mediates "neutral current" interactions (no charge change). Predicted by the theory and discovered at CERN (1973), spectacularly confirming electroweak unification.
Slide 09
CP Violation
- The universe distinguishes between matter and antimatter. CP violation (charge-conjugation + parity) means physics is not perfectly symmetric under simultaneous exchange of particles with antiparticles and mirror reflection.
- History
- 1964: Cronin and Fitch discover CP violation in kaon decays (Nobel 1980)
- 1973: Kobayashi-Maskawa predict 3 generations of quarks are needed (Nobel 2008)
- 2001: BaBar and Belle confirm CP violation in B mesons
- 2019: LHCb observes CP violation in charm system
- Baryogenesis
- Sakharov conditions for generating matter-antimatter asymmetry require CP violation. The Standard Model has too little CP violation to explain the observed asymmetry -- new sources of CP violation must exist. One of the biggest mysteries in physics.
Slide 10
Neutrino Physics
- Originally thought massless, neutrinos were found to oscillate between flavors -- proving they have mass and providing the first definitive evidence for physics beyond the Standard Model.
- Oscillations
- A neutrino produced as electron-type can later be detected as muon-type. This requires mass differences between flavor states. Super-Kamiokande (1998) and SNO (2002) confirmed this. Nobel Prize 2015.
- Mass Hierarchy
- We know mass-squared differences but not the absolute scale or ordering. Is it "normal" (lightest is mostly electron-type) or "inverted"? DUNE and JUNO experiments aim to resolve this.
- Majorana vs. Dirac
- Are neutrinos their own antiparticles (Majorana) or distinct from antineutrinos (Dirac)? Neutrinoless double beta decay searches would confirm Majorana nature. Not yet observed.
- Sterile Neutrinos
- Hypothetical additional flavors that do not interact via any Standard Model force. Could be dark matter candidates. Anomalous results from some experiments remain unconfirmed.
Slide 11
Particle Accelerators
- The microscopes of particle physics. Higher energy probes smaller distances: E = hc/lambda. The LHC collides protons at 13.6 TeV, probing structures 10^-19 m.
- Large Hadron Collider
- 27 km circumference at CERN. Proton-proton collisions at 13.6 TeV. Found the Higgs (2012). Two general-purpose detectors (ATLAS, CMS) plus specialized ones (LHCb, ALICE). High-Luminosity upgrade (2029) will increase data 10x.
- Detectors
- Onion-layer structure: tracking (silicon pixels), calorimetry (energy measurement), muon chambers. Millions of channels recording 40 million collisions/second. Trigger systems select ~1000/second for storage.
- Future Machines
- FCC (Future Circular Collider, 91 km, 100 TeV pp), ILC/CLIC (e+e- precision Higgs factory), muon collider (compact, high energy). Each costs $10-30 billion and requires decades to build.
Slide 12
Beyond the Standard Model
- Despite its success, the Standard Model is incomplete. Several observations and theoretical puzzles demand new physics.
- Supersymmetry (SUSY)
- Every fermion has a boson partner and vice versa. Solves hierarchy problem, provides dark matter candidate, enables gauge coupling unification. No evidence yet despite LHC searches -- parameter space narrowing.
- Grand Unified Theories
- Merge strong and electroweak forces into one at ~10^16 GeV. Predict proton decay (not observed: lifetime > 10^34 years). SU(5), SO(10) models.
- String Theory
- Replaces point particles with 1D strings vibrating in 10/11 dimensions. Naturally includes gravity. No experimental predictions at accessible energies. Mathematically rich but physically untestable so far.
- Dark Matter Candidates
- WIMPs (not yet found), axions (light scalar solving the strong CP problem), sterile neutrinos, gravitinos. Direct detection, indirect detection, and collider searches continue.
Slide 13
The Discovery Timeline
- 1897Electron discovered (J.J. Thomson) -- first subatomic particle
- 1911Atomic nucleus discovered (Rutherford scattering)
- 1932Neutron (Chadwick), positron (Anderson) -- antimatter confirmed
- 1947Pion and strange particles discovered in cosmic rays
- 1956Neutrino detected (Cowan and Reines)
- 1964Quark model proposed (Gell-Mann, Zweig); CP violation found
- 1968Deep inelastic scattering reveals quarks inside protons (SLAC)
- 1974J/psi particle: charm quark confirmed (November Revolution)
- 1983W and Z bosons found at CERN (Rubbia, van der Meer)
- 1995Top quark found at Fermilab (mass ~173 GeV)
- 2000Tau neutrino directly observed (DONUT)
- 2012Higgs boson discovered at LHC
Slide 14
Antimatter
- Every particle has an antiparticle with opposite quantum numbers but identical mass. When particle meets antiparticle, they annihilate into pure energy (photons).
- Prediction and Discovery
- Dirac equation (1928) predicted antimatter. Anderson found the positron in cosmic rays (1932). Antiproton found at Berkeley (1955). Complete antiatoms (antihydrogen) trapped at CERN (2011).
- Matter-Antimatter Asymmetry
- The Big Bang should have produced equal amounts. Yet the universe is almost entirely matter. For every billion antimatter particles, there were a billion and one matter particles. What caused the asymmetry? Unsolved.
- Medical Applications
- PET scans (Positron Emission Tomography): radioactive tracers emit positrons that annihilate with electrons, producing detectable gamma rays. Widely used for cancer diagnosis and brain imaging.
Slide 15
The Strong CP Problem
- QCD has a natural parameter (theta) that would violate CP symmetry and give the neutron an electric dipole moment. Experiments show theta
- The Puzzle
- Nothing in the Standard Model forces theta to be small. Its natural value should be order 1. The extreme smallness of theta is one of the most striking fine-tuning problems in physics -- the strong CP problem.
- Proposed Solutions
- Peccei-Quinn symmetry + axion: A new symmetry dynamically drives theta to zero. Predicts a light pseudoscalar particle: the axion.
- Axion as dark matter: If axion mass is ~10^-5 eV, it could be the dark matter. Actively searched for (ADMX, CASPEr).
- Nelson-Barr models: CP is a good symmetry at high energies, spontaneously broken to generate CKM phase but not theta.
Slide 16
Collider Physics Methods
- How do we discover new particles? By colliding known particles at extreme energies and analyzing the debris with massive, sophisticated detectors.
- Cross Sections
- Probability of a specific interaction occurring, measured in barns (10^-24 cm^2). Higgs production cross section at LHC: ~50 pb -- one Higgs per 2 billion collisions.
- Luminosity
- Number of collisions per unit area per unit time. LHC delivers ~300 fb^-1/year. Higher luminosity means more rare events discovered -- statistical significance grows with sqrt(N).
- 5-Sigma Standard
- Particle physics requires 5 standard deviations (p Monte Carlo Simulation
- Billions of simulated collisions generated using QCD and detector models. Comparing data distributions to simulation reveals new physics as statistically significant excesses or deficits.
Slide 17
Quantum Field Theory
- The mathematical framework underlying the Standard Model. Particles are excitations of quantum fields; interactions are described by gauge symmetries.
- Gauge Invariance
- The requirement that physics is unchanged under local phase transformations necessitates force-carrying particles. U(1) demands the photon; SU(2) demands W/Z; SU(3) demands gluons. Symmetry dictates dynamics.
- Renormalization Group
- Physical quantities depend on the energy scale at which they are measured. Coupling constants "run" with energy. The three SM couplings nearly converge at 10^16 GeV -- suggesting unification.
- Feynman Diagrams
- Pictorial calculation tools. Each diagram represents a term in the perturbation expansion. Vertices, propagators, and loops encode amplitudes. Higher-loop diagrams give increasingly precise (but harder to compute) predictions.
Slide 18
Dark Matter Searches
- Multiple complementary strategies aim to identify the particle nature of dark matter -- the 27% of the universe that is invisible to light.
- Direct Detection
- Underground detectors (XENON-nT, LZ, PandaX) wait for dark matter particles to scatter off nuclei. Sensitivity now reaches cross sections of 10^-47 cm^2. No signal yet -- pushing WIMPs into increasingly constrained parameter space.
- Indirect Detection
- Search for products of dark matter annihilation in space: gamma rays (Fermi-LAT), positrons (AMS-02), neutrinos (IceCube). Galactic center excess is debated -- could be pulsars or dark matter.
- Collider Production
- LHC could produce dark matter particles, detected as "missing energy" (particles escaping without interacting). No excess observed so far in mono-X searches.
- Axion Searches
- ADMX uses tunable microwave cavities in strong magnetic fields to detect axion-to-photon conversion. ABRACADABRA and CASPEr use different techniques for different mass ranges.
Slide 19
The Hierarchy Problem
- Why is the Higgs mass (125 GeV) so much lighter than the Planck scale (10^19 GeV)? Quantum corrections should drive it to the highest energy scale in the theory.
- The Problem
- Loop diagrams from all particles coupling to the Higgs contribute quadratically divergent corrections to its mass. Keeping m_H = 125 GeV requires cancellation of these contributions to 1 part in 10^34 -- extreme fine-tuning.
- Proposed Solutions
- Supersymmetry: Boson and fermion loops cancel exactly
- Composite Higgs: Higgs is not fundamental but a bound state
- Extra dimensions: Gravity is diluted, actual Planck scale is lower
- Multiverse/anthropic: Fine-tuning is environmental selection
- Relaxion: Cosmological dynamics scan the Higgs mass
Slide 20
Flavor Physics
- Why three generations? Why those specific masses? The pattern of fermion masses and mixing angles remains one of the deepest unexplained features of the Standard Model.
- CKM Matrix
- Describes quark mixing between mass and weak-interaction eigenstates. 3 angles + 1 CP-violating phase. Near-diagonal: generations prefer not to mix. The origin of this structure is unknown.
- PMNS Matrix
- Analogous matrix for neutrino mixing. Large mixing angles (unlike quarks). Two are large, one is small. CP-violating phase being measured by current experiments (T2K, NOvA, DUNE).
- Mass Hierarchies
- Top quark is 300,000x heavier than up quark. Electron neutrino is
Slide 21
Anomalies and Tensions
- Several recent measurements show intriguing deviations from Standard Model predictions. Any confirmed anomaly would be the first direct evidence for new physics at the LHC.
- Muon g-2
- The muon's magnetic moment deviates from SM prediction by ~4-5 sigma (combining Fermilab + BNL data). Could indicate new particles in loops. But lattice QCD calculations partially close the gap -- situation unresolved.
- B-Meson Anomalies
- LHCb and Belle II measure B-meson decays. Some branching ratios deviate from predictions. Potential lepton universality violation? Individual significance is 2-3 sigma; overall pattern is suggestive but not conclusive.
- W Boson Mass
- CDF II (2022) measured M_W = 80,433 MeV, 7 sigma above SM prediction. But ATLAS, LHCb, and CMS measurements agree with SM. Likely systematic issues in CDF measurement.
Slide 22
Cosmology Connections
- Particle physics and cosmology are deeply intertwined -- the early universe was a high-energy particle physics experiment.
- Big Bang Nucleosynthesis
- 3 minutes after the Big Bang: protons and neutrons fuse into light nuclei (H, He, Li). Predictions match observations perfectly with 3 light neutrino species -- a triumph of particle cosmology.
- Baryogenesis
- The matter-antimatter asymmetry requires new CP violation, baryon number violation, and departure from thermal equilibrium (Sakharov conditions). Electroweak baryogenesis, leptogenesis, and Affleck-Dine mechanisms are studied.
- Dark Energy
- Vacuum energy from quantum fields should equal 10^120 times observed dark energy. The cosmological constant problem is the worst prediction in physics history. No satisfactory explanation exists.
- Inflation
- A scalar field (inflaton) drove exponential expansion. Its nature is unknown but connects to BSM physics. Some models link the inflaton to the Higgs sector or supersymmetric fields.
Slide 23
Experimental Frontiers
- Energy Frontier
- Push to higher collision energies. LHC at 14 TeV. Proposed FCC at 100 TeV could directly produce particles up to ~30 TeV mass. Multi-TeV muon collider as alternative.
- Intensity Frontier
- Produce enormous numbers of particles to find rare processes. Mu2e (muon conversion), Belle II (B physics), DUNE (neutrinos). Sensitivity to new physics via virtual effects at very high mass scales.
- Cosmic Frontier
- Use the universe as a laboratory. Dark matter detectors, neutrino telescopes, gravitational wave observatories. Nature provides energies and volumes no accelerator can match.
- Precision Frontier
- Measure known quantities to extreme precision. Deviations reveal new physics. Electron EDM, proton radius, alpha_s at 0.1% -- precision kills or confirms theories.
Slide 24
Cosmic Ray Physics
- Cosmic rays are high-energy particles arriving from space -- protons, heavier nuclei, and electrons spanning 12 orders of magnitude in energy, up to 10^20 eV. They are natural particle beams from extreme astrophysical sources.
- The Knee and Ankle
- The cosmic ray energy spectrum follows a power law (E^-2.7) with a "knee" at 3 x 10^15 eV where it steepens and an "ankle" at 3 x 10^18 eV where it flattens. These features likely reflect the transition from galactic to extragalactic origin and different source populations.
- Air Showers
- A primary cosmic ray initiates a cascade of billions of secondary particles in the atmosphere (extensive air shower). Detected at ground level by surface arrays (Auger, TA) or via fluorescence of atmospheric nitrogen.
- Ultra-High Energy Cosmic Rays
- Above 6 x 10^19 eV (GZK limit) protons interact with CMB photons and lose energy rapidly. Pierre Auger Observatory finds these ultra-HECRs arrive anisotropically -- evidence of nearby extragalactic sources such as AGN.
- Composition Mystery
- At the highest energies the composition appears to be increasingly heavy nuclei (iron) rather than protons -- unexpected and still debated. Complicates source identification because heavy nuclei are deflected more by magnetic fields.
Slide 25
Hadron Spectroscopy
- The zoo of composite particles made from quarks reveals the richness of QCD. Mesons (quark-antiquark) and baryons (three quarks) are organized by symmetry into the "Eightfold Way."
- Baryons
- Proton (uud, stable), neutron (udd, 15 min free lifetime), and heavier resonances: Delta, Lambda, Sigma, Xi, Omega. The Omega-minus was predicted by the Eightfold Way and found precisely as expected (Brookhaven, 1964).
- Mesons
- Pions (lightest: pi+, pi-, pi0), kaons (contain strange quarks), D-mesons (charm), B-mesons (bottom). Each has an antiparticle partner. Pi-zero decays to two photons in 8 x 10^-17 seconds.
- Exotic Hadrons
- Tetraquarks (4 quarks) and pentaquarks (5 quarks) were predicted theoretically but only confirmed in 2015-2022 at LHCb. Hundreds of new exotic states discovered. Glueballs (pure gluon bound states) predicted but not yet confirmed.
- Quark-Gluon Plasma
- At extreme temperatures (2 x 10^12 K), hadrons dissolve into a plasma of free quarks and gluons -- the state of matter microseconds after the Big Bang. Created at RHIC (Brookhaven) and LHC ALICE. Behaves as a nearly perfect fluid.
Slide 26
Precision Tests of the Standard Model
- The Standard Model's predictions have been tested to extraordinary precision. Agreement with experiment is its greatest triumph -- and makes anomalies even more significant.
- Hall of Fame Predictions
- W boson mass: predicted vs. measured to 0.1%
- Electron anomalous magnetic moment: 12 decimal places (g-2)
- Z boson properties: LEP measured thousands of observables
- Weak mixing angle: same value from many independent processes
- Running of coupling constants with energy
- Electroweak Precision Tests
- LEP at CERN collided electrons and positrons at the Z-pole (91 GeV) from 1989-2000. The detailed line shape of Z production constrains the number of light neutrino species to exactly 3, rules out hundreds of proposed BSM models, and predicted the top quark mass before its discovery at Fermilab in 1995.
Slide 27
Grand Unified Theories
- At very high energies (~10^16 GeV), the three forces of the Standard Model appear to unify into a single force. GUTs attempt to describe this unification mathematically.
- Coupling Unification
- The three Standard Model coupling constants "run" with energy. In the Standard Model alone they nearly meet at ~10^16 GeV. With supersymmetry they meet precisely -- a major motivation for SUSY. In non-SUSY GUTs the meeting is approximate.
- Proton Decay
- GUTs generically predict proton decay via X,Y gauge bosons (mass ~10^16 GeV). Lifetime predictions: 10^31-10^36 years. Super-Kamiokande limit: >10^34 years for p→e+pi0. Constrains and rules out many simple GUT models.
- Magnetic Monopoles
- GUT symmetry breaking inevitably produces topological defects: magnetic monopoles with mass ~10^16 GeV. Never observed. The inflationary solution to the monopole problem is one of inflation's strong motivations.
- Leptoquarks
- GUT particles mediating baryon-lepton number violation. Could explain B-meson anomalies. Searched for at LHC via pair production. Constraints push masses above ~1-2 TeV for various quantum numbers.
Slide 28
Particle Physics and the Early Universe
- The first microseconds after the Big Bang were a high-energy particle physics experiment. Cosmological observations provide complementary tests of particle physics models.
- Phase Transitions
- Planck epoch (10^-43 s): Gravity unified? Unknown physics
- GUT transition (~10^-36 s): Strong separates; inflation begins?
- Electroweak transition (~10^-12 s): Higgs field acquires VEV; baryogenesis?
- QCD transition (~10^-6 s): Quark-gluon plasma freezes into hadrons
- BBN (3 min): Light nuclei form; counts neutrino species
- WIMP Miracle
- A stable particle with weak-scale mass (~100 GeV) and weak interactions naturally produces the observed dark matter density through thermal freeze-out in the early universe. This "WIMP miracle" motivated decades of searches. The null results from direct detection and LHC are forcing the community to consider lighter or more weakly-coupled candidates.
Slide 29
Neutrino Oscillation Physics
- The discovery that neutrinos change flavor while traveling (neutrino oscillations) was the first confirmed observation of physics beyond the Standard Model. The phenomenon is now measured with high precision.
- Solar Neutrino Problem
- The Sun produces far fewer electron neutrinos than predicted. Homestake mine detector (Ray Davis) found only 1/3 expected. Resolved by SNO (2002): the "missing" neutrinos had changed flavor. Total flux matches solar model predictions perfectly.
- Atmospheric Neutrinos
- Cosmic ray muons produce muon neutrinos. Super-Kamiokande (1998) found fewer muon neutrinos from below (traveled through Earth) than above -- they had oscillated into tau neutrinos. First confirmed oscillation evidence. Nobel Prize 2015.
- Oscillation Parameters
- Six parameters govern oscillations: three mixing angles (theta_12, theta_23, theta_13), one CP-violating phase (delta), and two mass-squared differences. All measured except the sign of delta (CP in leptons) -- the target of DUNE and Hyper-K.
- Mass Ordering
- Is m3 the heaviest (normal) or lightest (inverted) state? JUNO (China, 2024) and DUNE aim to resolve this using reactor and accelerator neutrinos respectively. Critical for neutrinoless double beta decay predictions.
Slide 30
Summary
- Particle physics has built an extraordinarily successful model of fundamental matter and forces -- yet we know it is incomplete. The next decades will either confirm this framework or revolutionize it.
- What We Know
- 17 fundamental particles, 3 forces, 1 Higgs field. All predicted particles discovered. Precision tests verified to parts per trillion. The Standard Model works magnificently.
- What We Don't Know
- Dark matter identity, matter-antimatter asymmetry, neutrino mass mechanism, hierarchy problem, quantum gravity, dark energy, and why the specific values of 19 free parameters.
- The Quest Continues
- The LHC, neutrino experiments, dark matter searches, precision measurements, and proposed future colliders all aim at the same goal: finding the cracks that reveal a deeper theory beneath the Standard Model.
