Latest / The Quark Side - Quantum Physics Podcast / The Neutrino Mystery Enters a New Era

Transcript

The Neutrino Mystery Enters a New Era · The Quark Side - Quantum Physics Podcast

• 0:01
  Speaker 1: Welcome to the quark Side. Quantum Physics podcast, an exploration
• 0:05
  Speaker 1: of the fundamental structure of reality where quantum laws govern matter, energy,
• 0:11
  Speaker 1: and information. Here, uncertainty is a feature, not a flaw,
• 0:16
  Speaker 1: and understanding begins with the smallest scales.
• 0:27
  Speaker 2: Take a second wherever you are right now, and just
• 0:30
  Speaker 2: look down at your hand.
• 0:31
  Speaker 3: Yeah, just really look at it, right.
• 0:32
  Speaker 2: Like if you flex your fingers or look at your palm.
• 0:35
  Speaker 2: It seems like this completely impenetrable wall of you know, skin,
• 0:41
  Speaker 2: bone and muscle. Like you knock on a wooden door
• 0:43
  Speaker 2: and your hand stops dead.
• 0:45
  Speaker 3: It feels completely solid.
• 0:46
  Speaker 2: Exactly, the electromagnetic repulsion between the atoms in your hand
• 0:50
  Speaker 2: and the atoms in the door. It creates this this
• 0:54
  Speaker 2: illusion of absolute solidity, right.
• 0:57
  Speaker 4: But I mean it is an incredibly persistent illusion because
• 1:00
  Speaker 4: from the perspective of the broader universe, your hand, the door,
• 1:03
  Speaker 4: the chair you're sitting on, they're basically ghost towns. The
• 1:07
  Speaker 4: doors are just blown wide open because at this exact second,
• 1:11
  Speaker 4: there are roughly sixty five billion tiny cosmic particles passing
• 1:16
  Speaker 4: through every single square centimeter of your body.
• 1:19
  Speaker 2: Oh wait, sixty five billion, yeah, per square centimeter, every
• 1:23
  Speaker 2: single second that is just it's staggering. And the craziest
• 1:26
  Speaker 2: part is they aren't just random cosmic dust, right. These
• 1:28
  Speaker 2: are neutrinos, right, neutrinos. And some of them are like
• 1:31
  Speaker 2: freshly forged in the nuclear furnace of our Sun, screaming
• 1:35
  Speaker 2: outward at nearly the speed of light.
• 1:37
  Speaker 3: Yeah.
• 1:37
  Speaker 4: And others are ancient, I mean literally ancient relics. They're
• 1:41
  Speaker 4: leftover background radiation from the Big Bang itself.
• 1:45
  Speaker 1: Wow.
• 1:45
  Speaker 4: So they have been whizzing through the vacuum of space
• 1:48
  Speaker 4: for you know, almost fourteen billion years, and right now
• 1:53
  Speaker 4: they are silently flooding through your living room, passing straight
• 1:57
  Speaker 4: through the Earth's crust and just coming out the other
• 1:59
  Speaker 4: side into the vacuum of space without hitting a single atom.
• 2:02
  Speaker 2: It's wild. And they bypass normal matter because they only
• 2:05
  Speaker 2: interact via the weak nuclear force and gravity right exactly.
• 2:08
  Speaker 4: They have no electrical charge, and their mass is so
• 2:13
  Speaker 4: so vanishingly small that for decades physicists actually assumed they
• 2:17
  Speaker 4: had absolute zero mass.
• 2:19
  Speaker 2: They just assumed they weighed nothing, right.
• 2:21
  Speaker 4: I mean, a neutrino can pass through a block of
• 2:23
  Speaker 4: solid lead a light year thick, and there's a fifty
• 2:25
  Speaker 4: percent chance it wouldn't hit a single thing.
• 2:27
  Speaker 2: A light year of lead.
• 2:28
  Speaker 4: Yeah, their probability of interacting with matter, which physicists call
• 2:32
  Speaker 4: their cross section, is almost zero.
• 2:35
  Speaker 2: Which I mean that sets up one of the greatest
• 2:37
  Speaker 2: engineering challenges in human history. Oh, absolutely, because if a
• 2:41
  Speaker 2: particle can sail through a light year of lead, how
• 2:44
  Speaker 2: do you catch it?
• 2:45
  Speaker 3: Right? How do you even see it? Yeah?
• 2:47
  Speaker 2: If the universe is absolutely drenched in these things, but
• 2:50
  Speaker 2: they slip through everything like phantoms, how do we prove
• 2:54
  Speaker 2: they are there, let alone measure them? I mean we
• 2:56
  Speaker 2: have to build.
• 2:57
  Speaker 3: A trap, and not just any trap.
• 2:59
  Speaker 2: Right. You don't just set up a telescope in your
• 3:01
  Speaker 2: backyard or build a standard particle collider. You have to
• 3:04
  Speaker 2: go underground, specifically to Kaikeping in southern China's Guangdong Province.
• 3:11
  Speaker 4: Right, the Jiongman Underground Neutrino Observatory.
• 3:14
  Speaker 2: Jay, you know, Jay?
• 3:15
  Speaker 3: You know? Yeah?
• 3:15
  Speaker 4: It is basically an absolute cathedral of modern physics. It
• 3:19
  Speaker 4: situated seven hundred meters so nearly half a mile straight
• 3:22
  Speaker 4: down into solid granite.
• 3:23
  Speaker 2: Which is fascinating because the intuition for most people when
• 3:26
  Speaker 2: studying cosmic phenomena is to go high.
• 3:29
  Speaker 4: Right, Yeah, you think of telescopes on mountains.
• 3:31
  Speaker 2: Exactly. You build observatories on the peaks of mountains in
• 3:34
  Speaker 2: Chile or Hawaii to get away from the atmosphere and
• 3:37
  Speaker 2: get closer to space. But here the science demands the
• 3:41
  Speaker 2: exact opposite it does.
• 3:42
  Speaker 4: And what's fascinating here is that the surface of the
• 3:45
  Speaker 4: Earth is actually incredibly noisy on a subatomic level. Oh interesting, Yeah,
• 3:49
  Speaker 4: we are constantly being bombarded by cosmic rays, and when
• 3:53
  Speaker 4: those high energy protons hit our upper atmosphere, they create
• 3:57
  Speaker 4: a shower of secondary particles, specifically muons. Okay, muons, right,
• 4:01
  Speaker 4: So if you put a delicate, highly sensitive neutrino detector
• 4:04
  Speaker 4: on the surface of the Earth, the constant rain of
• 4:06
  Speaker 4: muons whilch is completely blind the sensor.
• 4:09
  Speaker 2: You just wash everything out, exactly.
• 4:11
  Speaker 4: It would be like trying to study the acoustic properties
• 4:15
  Speaker 4: of a single snowflake falling in the middle of a screaming,
• 4:18
  Speaker 4: sold out stadium.
• 4:19
  Speaker 2: That is a great analogy. You'd never hear it, never.
• 4:23
  Speaker 4: So by burying the detector under seven hundred meters of granite,
• 4:26
  Speaker 4: you basically use the Earth itself as a giant filter.
• 4:29
  Speaker 4: The rock absorbs the muons and all that other background.
• 4:32
  Speaker 2: Radiation, weaving total absolute silence, and in that silence, only
• 4:38
  Speaker 2: the ghostly neutrinos, which you know they don't care about
• 4:41
  Speaker 2: the hundreds of meters of rock at all, can slip
• 4:43
  Speaker 2: into the cavern. But Jay, you know, is positioned in
• 4:46
  Speaker 2: Kaiping for a very specific reason. And it's not just
• 4:49
  Speaker 2: the quality of the granite, is it.
• 4:51
  Speaker 4: No, it's not. It's the location relative to two specific
• 4:55
  Speaker 4: nuclear power plants, the Taishan and Yangjang reactors.
• 4:58
  Speaker 2: Okay, so wait, let's unpack this because jone isn't actually
• 5:02
  Speaker 2: looking for cosmic neutrinos from space. It's looking for anti
• 5:05
  Speaker 2: neutrinos produced by those.
• 5:07
  Speaker 4: Reactors, right, Anti neutrinos, which are the equally mysterious opposite
• 5:12
  Speaker 4: versions of.
• 5:12
  Speaker 2: Neutrinos, Which sounds so complicated, like why look at anti
• 5:16
  Speaker 2: neutrinos to understand neutrinos. It's kind of like trying to
• 5:19
  Speaker 2: understand how a stealth jet works by studying its exact
• 5:23
  Speaker 2: mirror reflection in a puddle.
• 5:25
  Speaker 4: That's yeah, Actually, that's a really good way to put it.
• 5:27
  Speaker 4: Nuclear fission reactors are incredibly prolific anti neutrino factories. So
• 5:31
  Speaker 4: when uranium or plutonium undergoes beta decay in the reactor core,
• 5:35
  Speaker 4: they spit out an enormous, highly predictable flux of electron
• 5:39
  Speaker 4: anti neutrinos.
• 5:40
  Speaker 2: Highly predictable being the key phrase there.
• 5:43
  Speaker 4: Exactly, by positioning Geno exactly fifty three kilometers away from
• 5:47
  Speaker 4: both reactor complexes, physicists create what's known as a controlled baseline.
• 5:53
  Speaker 2: They know exactly what they're starting.
• 5:55
  Speaker 4: With, right, They know exactly how many antineutrinos are being produced,
• 5:58
  Speaker 4: and they know the exact since those particles have to
• 6:01
  Speaker 4: travel through the Earth before hitting the detector.
• 6:03
  Speaker 2: Okay, So I want to focus on the mechanics of
• 6:05
  Speaker 2: the trap itself, because the way Jano catches these anti
• 6:08
  Speaker 2: neutrinos is just it's a masterpiece of chemistry and optics.
• 6:12
  Speaker 4: It really is an engineering marvel.
• 6:14
  Speaker 2: So at the bottom of this cavern they have built
• 6:17
  Speaker 2: a massive acrylic sphere.
• 6:19
  Speaker 3: Yeah, it's huge.
• 6:19
  Speaker 2: It's one hundred and fifteen feet across, and it is
• 6:22
  Speaker 2: filled with twenty thousand tons of a highly purified transparent
• 6:28
  Speaker 2: liquid called liquid scintillator, right, which is.
• 6:30
  Speaker 4: Essentially a derivative of petroleum linear alkalbin zene.
• 6:34
  Speaker 2: Okay, And that liquid is surrounded by roughly forty three
• 6:37
  Speaker 2: thousand photomultiplier.
• 6:39
  Speaker 4: Tubes, which sounds intimidating, but they are basically ultra sensitive
• 6:43
  Speaker 4: cameras capable of detecting a single individual photon of light, a.
• 6:47
  Speaker 2: Single particle of light. So, an anti neutrino travels fifty
• 6:51
  Speaker 2: three kilometers from the nuclear reactor, passes through the solid rock,
• 6:55
  Speaker 2: and enters this dark sphere, right, And if it defies
• 6:58
  Speaker 2: the odds and actually hits proton in that liquid scentillator,
• 7:02
  Speaker 2: it triggers a reaction. But it's not just a random spark, right,
• 7:05
  Speaker 2: because they need to be sure. It's a very specific
• 7:08
  Speaker 2: two part sequence called in rease beta decay.
• 7:11
  Speaker 3: Yeah.
• 7:11
  Speaker 4: The physics of inverse beta decay is just brilliant.
• 7:14
  Speaker 2: Okay.
• 7:15
  Speaker 4: So when the antiineutrino hits the proton, it transforms the
• 7:18
  Speaker 4: proton into a neutron and spits out a positron, which
• 7:22
  Speaker 4: is the antimatter equivalent of an electron. Okay, antimatter, right,
• 7:25
  Speaker 4: And that positron immediately collides with a regular electron and
• 7:29
  Speaker 4: the liquid and because matter and antimatter annihilate each other,
• 7:33
  Speaker 4: they vanish in a tiny flash of gamma rays.
• 7:35
  Speaker 2: So that's the first flash that's the first flash. But
• 7:38
  Speaker 2: the detector doesn't just record that flash and call it
• 7:40
  Speaker 2: a day, because I mean random background radiation could cause
• 7:43
  Speaker 2: a similar blip exactly.
• 7:45
  Speaker 3: It waits for the echo.
• 7:46
  Speaker 2: The echo. I love that.
• 7:47
  Speaker 3: Yeah.
• 7:48
  Speaker 4: Remember that neutron we created in the initial collision. It
• 7:51
  Speaker 4: wanders around in the liquid for about two hundred microseconds,
• 7:54
  Speaker 4: just losing energy until it gets captured by a hydrogen nucleus.
• 7:58
  Speaker 2: And when that capture happens, it.
• 7:59
  Speaker 4: Releases a second, slightly more energetic flash of light.
• 8:03
  Speaker 2: It's a delayed coincidence. That's the fingerprint precisely. So you
• 8:06
  Speaker 2: see the positron flash, you start a microscopic stopwatch, and
• 8:09
  Speaker 2: exactly two hundred microseconds later you see the neutron flash.
• 8:13
  Speaker 2: It's like setting a giant pitch black tripwire and waiting
• 8:17
  Speaker 2: for a microscopic spark.
• 8:18
  Speaker 3: Yeah.
• 8:19
  Speaker 2: It's the subatomic equivalent of seeing a bolt of lightning,
• 8:23
  Speaker 2: counting the seconds and waiting for the exact corresponding crack
• 8:27
  Speaker 2: of thunder to confirm it wasn't just you know, a
• 8:30
  Speaker 2: strobe light in the distance.
• 8:32
  Speaker 3: That is exactly it.
• 8:33
  Speaker 4: That double flash is the unmistakable signature of an anti
• 8:36
  Speaker 4: neutrino interaction. The photo multiplayer tubes pick up those microscopic
• 8:41
  Speaker 4: bursts of photons, convert them into electrical signals, and suddenly
• 8:45
  Speaker 4: you have trapped your.
• 8:47
  Speaker 2: Ghost, which brings us to the actual data. Because setting
• 8:50
  Speaker 2: this massive underground tripwire and trapping the ghost is just
• 8:54
  Speaker 2: step one. What scientists are really hoping to see when
• 8:57
  Speaker 2: those flashes go off is what these particles are doing
• 8:59
  Speaker 2: as they travel that fifty three kilometers.
• 9:01
  Speaker 4: And they are doing some very weird things, very weird.
• 9:05
  Speaker 2: Just this Wednesday, the Jauno team published their initial findings
• 9:09
  Speaker 2: in the journal Nature, based on the first two months
• 9:12
  Speaker 2: of data collection, which just started in August.
• 9:14
  Speaker 3: Yeah, it's very fresh data, and.
• 9:15
  Speaker 2: Even in that short window, they are zeroing in on
• 9:18
  Speaker 2: one of the most bizarre phenomena in quantum mechanics, which
• 9:21
  Speaker 2: is neutrino oscillation or flavor switching.
• 9:24
  Speaker 4: Right, So, neutrino's come in three distinct varieties or flavors
• 9:27
  Speaker 4: in physics terminology, you know, the electron neutrino, the mewon neutrino,
• 9:31
  Speaker 4: and the town neutrino. Okay, the bizarre thing is that
• 9:33
  Speaker 4: a neutrino doesn't maintain its flavor as it travels through space.
• 9:37
  Speaker 4: An electron neutrino can spontaneously morph into a muon neutrino,
• 9:41
  Speaker 4: and then into a town neutrino and back again.
• 9:44
  Speaker 2: Right. And here's where it gets really interesting, because I
• 9:47
  Speaker 2: want to break down how this happens. The standard explanation
• 9:50
  Speaker 2: you always hear is the sports ball analogy. You throw
• 9:53
  Speaker 2: a baseball halfway to the plate, it turns into a
• 9:55
  Speaker 2: tennis ball and it lands in the catcher's mid as
• 9:58
  Speaker 2: a golf ball.
• 9:59
  Speaker 3: Yeah, that one all the time.
• 10:01
  Speaker 2: But that doesn't actually explain the physics. It just describes
• 10:04
  Speaker 2: the magic trick exactly.
• 10:05
  Speaker 4: It doesn't tell you why.
• 10:07
  Speaker 2: Right. The actual mechanism relies on quantum superposition.
• 10:12
  Speaker 4: Right, So a neutrino doesn't actually have a single defined mass.
• 10:16
  Speaker 2: Which is so hard to wrap your head around.
• 10:18
  Speaker 3: It really is.
• 10:19
  Speaker 4: There are three different mass states, mass one, mass two,
• 10:22
  Speaker 4: and mass three. An electron neutrino isn't just mass one.
• 10:26
  Speaker 4: It is a quantum mixture, like a specific recipe of
• 10:29
  Speaker 4: all three mass states existing simultaneously.
• 10:32
  Speaker 2: Okay, so the best way to visualize this isn't a
• 10:35
  Speaker 2: baseball changing into a tennis ball. It's more like a
• 10:37
  Speaker 2: musical chord. Let's say an electron neutrino is a C
• 10:40
  Speaker 2: major chord played on a piano.
• 10:42
  Speaker 3: Okay, I like this.
• 10:43
  Speaker 2: It's made of three distinct notes, C, E, and G.
• 10:48
  Speaker 2: Those three notes represent the three mass states. When the
• 10:52
  Speaker 2: nuclear reactor creates the antimutrino, it strikes that exact chord.
• 10:56
  Speaker 2: But here's the catch. The universe is a slightly of
• 11:00
  Speaker 2: tune piano. Because the three notes the three mass states
• 11:04
  Speaker 2: have slightly different weights, their waves travel at minutely different speeds.
• 11:09
  Speaker 4: Exactly so, as the chord travels fifty three kilometers through
• 11:12
  Speaker 4: the Earth, the waves of those three notes drift out
• 11:15
  Speaker 4: of phase with each other.
• 11:16
  Speaker 3: They begin to interfere.
• 11:18
  Speaker 2: So if you listen to that sound wave immediately after
• 11:20
  Speaker 2: it struck, it sounds like C major. But if you
• 11:22
  Speaker 2: stand ten kilometers away, the waves have overlapped differently, and
• 11:26
  Speaker 2: suddenly the E note is the loudest. It sounds like
• 11:28
  Speaker 2: a completely different chord. That's the muon flavor. By the
• 11:31
  Speaker 2: time it hits the detector fifty three kilometers away, the
• 11:34
  Speaker 2: quantum waves have shifted again. Depending on exactly where you
• 11:36
  Speaker 2: stand to listen the baseline distance, you hear a different flavor.
• 11:39
  Speaker 4: That is a perfect way to explain it. The changing
• 11:42
  Speaker 4: flavor is just the observable result of those three different
• 11:45
  Speaker 4: mass waves shifting in and out of alignment over distance.
• 11:48
  Speaker 3: Wow.
• 11:49
  Speaker 4: And that actually brings us to the core mystery JUNO
• 11:53
  Speaker 4: was built to solve, which is the mass hierarchy.
• 11:56
  Speaker 2: Probably, okay, the mass hierarchy.
• 11:58
  Speaker 3: Right.
• 11:58
  Speaker 4: We know these three mass states exist, and we know
• 12:00
  Speaker 4: they interfere with each other from decades of previous experiments.
• 12:04
  Speaker 4: We know the exact difference in weight between mass one
• 12:08
  Speaker 4: and mass two. They're very close together.
• 12:11
  Speaker 2: But mass three is the odd.
• 12:12
  Speaker 4: Ball, exactly. Mass three is the odd ball. We know
• 12:15
  Speaker 4: it's significantly different from the other two, but we do
• 12:18
  Speaker 4: not know if it is much heavier than one and
• 12:21
  Speaker 4: two or much lighter.
• 12:23
  Speaker 2: It's like watching a street magician juggle three identical looking boxes,
• 12:27
  Speaker 2: right right. You know two have feathers and one has
• 12:29
  Speaker 2: a brick, or maybe two have bricks and one has feathers,
• 12:31
  Speaker 2: but they keep changing colors in mid air, so you
• 12:33
  Speaker 2: can't pin down which is which.
• 12:35
  Speaker 4: That's exactly the problem. And if mass three is the heaviest,
• 12:39
  Speaker 4: physicists call that the normal ordering. If mass three is
• 12:42
  Speaker 4: the lightest, sitting beneath one and two, it's the inverted ordering.
• 12:47
  Speaker 2: And this isn't just, you know, a bookkeeping issue for physicists.
• 12:50
  Speaker 2: Knowing the order of those masses dictates our entire understanding
• 12:54
  Speaker 2: of the standard model of particle physics.
• 12:56
  Speaker 3: Oh, it's huge.
• 12:57
  Speaker 2: It ties into fundamental questions about the big band, like
• 13:01
  Speaker 2: if we figure out the mass hierarchy, it helps us
• 13:04
  Speaker 2: understand why neutrinos behave differently than anti neutrinos, which could
• 13:08
  Speaker 2: explain why the universe is made of matter instead of
• 13:11
  Speaker 2: anti matter.
• 13:11
  Speaker 3: You're right.
• 13:12
  Speaker 4: It could explain why we even exist, rather than the
• 13:15
  Speaker 4: universe just instantly annihilating itself right after it was born.
• 13:18
  Speaker 2: Which is just a massive question to be answering with
• 13:21
  Speaker 2: flashes of light underground.
• 13:22
  Speaker 4: It is, and if we connect this to the bigger picture,
• 13:25
  Speaker 4: that is why the new Nature paper from the Jano
• 13:28
  Speaker 4: collaboration is generating such immense excitement. The initial two months
• 13:33
  Speaker 4: of results haven't fully solved the weight mystery yet, they
• 13:36
  Speaker 4: haven't definitively declared normal or inverted ordering.
• 13:40
  Speaker 2: Right, two months isn't enough time, No, But.
• 13:42
  Speaker 4: They have achieved something equally vital. They have mapped the
• 13:45
  Speaker 4: oscillation waves, the shifting notes of our musical chord with
• 13:49
  Speaker 4: unprecedented precision.
• 13:51
  Speaker 2: Right, they measured two specific parameters what physicists call signs
• 13:55
  Speaker 2: squared Theta twelve and delta M squared twenty one. They
• 14:00
  Speaker 2: essentially measured the exact frequency of how the notes go
• 14:03
  Speaker 2: out of tune. Leon jan when a co author of
• 14:07
  Speaker 2: the study noted that JNO is unique because it can
• 14:09
  Speaker 2: observe two different oscillation frequencies, a fast ripple and a
• 14:13
  Speaker 2: slow ripple simultaneously in the exact same data set.
• 14:17
  Speaker 4: Yes, they are essentially proving that their microphone is sensitive
• 14:21
  Speaker 4: enough to hear the absolute finest harmonic distortions in the cord.
• 14:25
  Speaker 4: The mass hierarchy difference is a tiny, subtle effect layered
• 14:29
  Speaker 4: on top of the main oscillation.
• 14:31
  Speaker 2: You'd need a ridiculous amount of resolution to see it exactly.
• 14:34
  Speaker 4: You need a detector with incredible energy resolution. And JNO
• 14:37
  Speaker 4: has proven with this initial data that it's twenty thousand
• 14:40
  Speaker 4: tons of liquid scintillator and forty three thousand photo multiplier
• 14:44
  Speaker 4: tubes have the exact sensitivity required to eventually tease out
• 14:48
  Speaker 4: that mass ordering.
• 14:49
  Speaker 2: But you know, JANO has proven it has the sensitivity.
• 14:52
  Speaker 2: But confirming something this fundamental to the universe requires a
• 14:55
  Speaker 2: global effort. It requires triangulation.
• 14:57
  Speaker 3: Oh. Absolutely.
• 14:58
  Speaker 2: The international physics community, people like Kate Schulberg at Duke University,
• 15:01
  Speaker 2: are incredibly energized by these jaun No results, and it
• 15:05
  Speaker 2: makes them look forward to more thrilling results. But they
• 15:08
  Speaker 2: are also looking at the next decade of infrastructure because
• 15:12
  Speaker 2: JNO isn't going to be alone in this search.
• 15:14
  Speaker 3: No, not at all.
• 15:15
  Speaker 2: There are two other massive underground cathedrals currently under construction,
• 15:20
  Speaker 2: the Hypercomoconde in Japan and the Deep Underground Neutrino Experiment
• 15:24
  Speaker 2: or a DOA in the United States.
• 15:27
  Speaker 4: And this raises an important question, Right, why do we
• 15:29
  Speaker 4: need Japan and the US to join this effort over
• 15:32
  Speaker 4: the next decade?
• 15:33
  Speaker 2: Right if JNO can just do it exactly?
• 15:36
  Speaker 4: The necessity of those projects lies in the core philosophy
• 15:39
  Speaker 4: of the scientific method.
• 15:40
  Speaker 2: You have to double check the work.
• 15:42
  Speaker 4: You have to if JENO announces the mass hierarchy in
• 15:45
  Speaker 4: three years, we can't simply rewrite the physics textbooks based
• 15:48
  Speaker 4: on a single detector using a single method. You have
• 15:51
  Speaker 4: to aggressively combat systemic error.
• 15:54
  Speaker 3: What if there's a.
• 15:54
  Speaker 4: Fundamental quirk in how liquid scintillator reacts? Right, what if
• 15:58
  Speaker 4: the fifty three kilometer base from a reactor introduces some
• 16:02
  Speaker 4: kind of unforeseen bias.
• 16:03
  Speaker 2: So you don't just build a carbon copy of Jono
• 16:06
  Speaker 2: in Nevada to double check the math. You attack the
• 16:09
  Speaker 2: problem from completely different technological angles.
• 16:11
  Speaker 4: Completely different So hyper cameoconde, for instance, doesn't use liquid scintillator.
• 16:17
  Speaker 4: It uses highly purified water water, just water, just water,
• 16:21
  Speaker 4: And it doesn't look for inverse beta decay. It looks
• 16:23
  Speaker 4: for sharing CoV radiation. So when a neutrino hits a
• 16:27
  Speaker 4: water molecule and creates a charged particle moving faster than
• 16:31
  Speaker 4: the speed of light and water, wait, faster than light,
• 16:33
  Speaker 4: faster than light travels in water?
• 16:35
  Speaker 2: Yes, oh, okay, got it.
• 16:36
  Speaker 4: When that happens, it creates a faint blue cone shaped
• 16:40
  Speaker 4: shockwave of light. It's like a sonic boom, but for.
• 16:43
  Speaker 2: Light that is incredible and doon. He takes an even
• 16:46
  Speaker 2: more radical approach, right Oh yeah. Demi is being built
• 16:49
  Speaker 2: in South Dakota a mile underground and an old gold mine,
• 16:52
  Speaker 2: and it will use massive tanks of liquid argon kept
• 16:56
  Speaker 2: at nearly three hundred degrees below zero.
• 16:58
  Speaker 4: Which is a huge engineering challenge on its.
• 17:00
  Speaker 2: Own right, And instead of catching flashes of light liquid
• 17:04
  Speaker 2: argon time projection chambers essentially record a highly detailed three
• 17:09
  Speaker 2: D video of the ionized tracks left behind when a
• 17:12
  Speaker 2: neutrino shatters an argon nucleus.
• 17:15
  Speaker 4: It's totally different, and the baselines are entirely different too.
• 17:18
  Speaker 4: Jno relies on reactor antineutrinos traveling fifty three kilometers. Jato
• 17:23
  Speaker 4: is going to use a massive particle accelerator at Fermo
• 17:25
  Speaker 4: Lab near Chicago to generate a high intensity beam of
• 17:29
  Speaker 4: muon neutrinos. A beam, yes, and they'll fire that beam
• 17:32
  Speaker 4: straight through the Earth's mantle thirteen hundred kilometers to South Dakota.
• 17:36
  Speaker 2: Firing a beam of ghost particles straight through the Earth's crust.
• 17:40
  Speaker 2: It sounds like science fiction, But the distance is the point,
• 17:43
  Speaker 2: isn't it. Because when neutrinos travel thirteen hundred kilometers through
• 17:46
  Speaker 2: solid rock, they interact with the electrons in the dirt right.
• 17:50
  Speaker 3: It's called the MSW effect.
• 17:51
  Speaker 4: The normal matter of the Earth actually alters the flavor
• 17:54
  Speaker 4: switching of the neutrinos. So by analyzing how the dense
• 17:57
  Speaker 4: rock alters the oscillation over thirteen one hundred kilometers with
• 18:01
  Speaker 4: liquid argon and then comparing it to how fifty three
• 18:04
  Speaker 4: kilometers of rock alters reactor anti neutrinos in liquid scintillator.
• 18:09
  Speaker 4: Physicists can basically cross examine reality.
• 18:11
  Speaker 2: So if jan O, hyper k, and jew In all
• 18:14
  Speaker 2: independently point to the exact same mass hierarchy using vastly
• 18:18
  Speaker 2: different baseline distances, energy ranges, and detection mediums.
• 18:21
  Speaker 4: Then you haven't just spotted a trend. You've discovered an
• 18:25
  Speaker 4: undeniable fundamental truth of nature.
• 18:27
  Speaker 2: So what does this all mean? We are actively living
• 18:30
  Speaker 2: through a golden age of particle astrophysics. We are watching
• 18:34
  Speaker 2: human ingenuity scale up to almost unimaginable proportions to measure
• 18:38
  Speaker 2: the infinitely small I mean. We are digging out half
• 18:41
  Speaker 2: mile deep caverns in solid granite, filling one hundred and
• 18:44
  Speaker 2: fifteen foot spheres with twenty thousand tons of synthetic liquid,
• 18:48
  Speaker 2: and firing particle beams across entire continents.
• 18:51
  Speaker 4: All to catch the faintest fleeting echoes of a particle
• 18:53
  Speaker 4: that weighs almost nothing.
• 18:55
  Speaker 2: It's unbelievable.
• 18:56
  Speaker 4: It reveals a profound elegance in how the universe is constructed.
• 19:00
  Speaker 4: The macroscale engineering required to observe the subatomic world is staggering.
• 19:05
  Speaker 3: But the fact that we.
• 19:06
  Speaker 4: Can actually decode the quantum superposition of a particle born
• 19:10
  Speaker 4: in the core of a star just by waiting for
• 19:13
  Speaker 4: a delayed double flash of light underground. I mean it's
• 19:16
  Speaker 4: a triumph of deduction.
• 19:17
  Speaker 2: It completely reframes the concept of empty space. The space
• 19:21
  Speaker 2: between the screen you're looking at in your eyes isn't empty.
• 19:24
  Speaker 2: The space inside your own cells isn't empty. It is
• 19:27
  Speaker 2: roaring with this cosmic storm of subatomic architecture that we
• 19:31
  Speaker 2: simply lacked the biological senses to perceive.
• 19:34
  Speaker 3: We didn't even know it was there, right.
• 19:36
  Speaker 2: We only know neutrinos exists because a few decades ago
• 19:39
  Speaker 2: the mathematics of beta decay showed that some energy was
• 19:41
  Speaker 2: mysteriously missing. The math demanded an invisible particle to balance
• 19:46
  Speaker 2: the equation. So we spend a century inventing the technology to.
• 19:49
  Speaker 4: Catch them, and now we're catching them we are.
• 19:51
  Speaker 2: Which leaves you with a staggering thought to mull over
• 19:54
  Speaker 2: if sixty five billion ancient, nearly massless particles can stream
• 19:59
  Speaker 2: through your thumbnail every single second without you ever feeling
• 20:02
  Speaker 2: a tremor, and they only reveal themselves in highly controlled
• 20:06
  Speaker 2: seven hundred meters deep traps of liquid scintillator. What other
• 20:11
  Speaker 2: architectures are we entirely blind to? That is the question,
• 20:15
  Speaker 2: what other dark matter, or unrecognized forces, or bizarre quantum
• 20:19
  Speaker 2: phenomena are actively shaping the room you are sitting in
• 20:22
  Speaker 2: right now, just woven out of physics. We just haven't
• 20:25
  Speaker 2: written the math to look for yet.
• 20:27
  Speaker 4: It's the ultimate scientific motivator, because the things we can't
• 20:30
  Speaker 4: see are usually the things that define everything else.
• 20:33
  Speaker 2: Keep looking closely at the world around you, because the
• 20:36
  Speaker 2: deeper you go, the more you realize that even the
• 20:38
  Speaker 2: most solid, impenetrable surface is just a window into something
• 20:41
  Speaker 2: far more mysterious. Thanks for listening.