Chapter 268

At Geneva Airport, Xu Qingzhou had a half-hour long phone call with the school beauty Song. Only after hearing her yawn did he hang up and continue to look down at the materials.

At 8:00 PM, he waited for Academician Yang Bing and Wang Wang Shixiong Zhang Changqing.

"Academician Yang, Wang Wang Shixiong Zhang." Xu Qingzhou put the draft paper into his computer bag, stood up, and greeted them.

"Qingzhou, you've been waiting a long time, right?" Academician Yang said with a smile.

"No." Xu Qingzhou shook his head.

Seeing that Xu Qingzhou had just been looking at materials, Academician Yang said admiringly: "No wonder you can achieve such accomplishments; it's all about using the time others spend playing to do things. This is the reward for hard work."

Xu Qingzhou smiled helplessly: "I was just looking casually. In front of seniors like you, Academician Yang, how would I dare to boast about being hardworking."

The middle-aged man smiled and said: "You know, the Xia Nation has too few reserve talents in this field; this young man is worth cultivating."

Read! {

Abby Baker, the leader of the American team.

Another large-scale experiment is the upcoming CMS experiment, which uses the LHC to generate high-energy proton beams, accelerates them to near the speed of light, and then uses the CMS detector to record particle events generated by proton beam collisions.

After doing this, he went to take a shower to refresh himself.

Upon arriving at his accommodation, Xu Qingzhou took a photo to report his itinerary and told Song Yao that he had arrived.

Seeing Xu Qingzhou lost in thought, Wang Qiming looked up, and the resentment in his eyes grew.

There were only two people in the conference room.

"It seems he really doesn't like the look of me." Xu Qingzhou said.

"Analyzing the diphoton channel of the Higgs boson is a complex and delicate process..."

The members of the Xia Nation team gradually arrived—eight people. The slightly younger ones were Xu Qingzhou and a girl who looked to be twenty-six or twenty-seven.

The experiment mainly finds the Higgs boson from the two decay channels: diphoton and 4-lepton. After that, it studies the particle's decay mode, signal strength, and interaction strength with other particles.

"It's okay." Xu Qingzhou nodded.

What's more, in the next few decades, the Xia Nation will be able to lead the way.

"Did you sleep well last night?" Mao Yi asked with a smile.

"Therefore, the analysis plan for the diphoton channel will be provided by our Xia Nation team and the American team respectively. We will have a meeting in 5 days, and only one plan can pass. This also means that whoever has the better plan can lead this part of the experiment on diphoton channel analysis."

Half an hour passed, and the three people got off the car at the hotel entrance.

Xu Qingzhou nodded.

"The main goal of the first phase is to analyze the diphoton channel to find the Higgs boson. The production rate of Higgs to diphoton is very low, while the background production rate is 12 orders of magnitude higher."

"Two years have passed since the first confirmation of the Higgs boson, but the number of actual experiments can be counted on one's fingers, after all..."

"This young man also has great insights into quantum physics. I have read one of his articles, and it was written very well."

On the balcony, Zhang Changqing looked around and, seeing no one else, asked Xu Qingzhou in a low voice: "Did Professor Wang Qiming give you a cold shoulder?"

"You are also still young."

Xu Qingzhou listened quietly; he had actually known about these things Academician Yang mentioned for a long time.

According to the Xia Nation's schedule, it was time to sleep now. Although he had slept for three or four hours during the day, his biological clock was already set, so he was extremely sleepy now.

Xu Qingzhou greeted them; both of these people were experts in particle physics.

"Thank you. To be honest, in my opinion, meeting old friends is much more interesting than going to a cocktail party."

But as long as it involves things between nations, nothing is simple.

Wang Qiming glanced at Xu Qingzhou indifferently and nodded slightly. It couldn't be called enthusiastic; in fact, there was even a hint of hostility.

"The first method uses a data-driven approach to estimate background levels, such as the sideband data method or the control sample method. These methods use the experimental data itself to build a background model, thereby reducing reliance on external simulations."

Background refers to the contribution generated by all other physical processes unrelated to the Higgs signal during the detection process of the Higgs boson to diphoton decay channel. Simply put, it is irrelevant clutter.

"And for this experiment, in addition to the most basic CMS experiment, we also need the assistance of the ATLAS experiment. Therefore, the first stop is the Geneva headquarters, mainly to discuss the experimental plan with the ATLAS experimental group."

Xu Qingzhou followed Academician Yang and the others out of the airport, got into a black Audi, and drove toward the LHC headquarters in the suburbs of Geneva, the European Organization for Nuclear Research (CERN).

After chatting with Song Yao, Xu Qingzhou got up, finished washing, ate breakfast in the restaurant, and arrived at the conference room at 7:30.

Xu Qingzhou didn't feel surprised. Although most LHC experiments are completed under the model of international cooperation, what has always been promoted is gathering scientists from research institutions around the world to witness an exciting moment together.

Xu Qingzhou was originally thinking about how to solve the background problem when he was dragged to the restroom by Wang Wang Shixiong Zhang.

Academician Yang nodded, then turned to look at the European old man beside him: "Mr. Collins, we meet again."

Xu Qingzhou agreed very much. Modern physical theories basically originate from the West. It is already remarkable that the Xia Nation can catch up and have its current development.

"We all know that the production rate of Higgs to diphoton is very low. Therefore, the problem before us appears—how to effectively exclude the background."

After going to the restroom, Zhang Changqing took him to the balcony to breathe fresh air and asked at the same time: "Junior brother, how do you feel?"

ATLAS, the A Toroidal LHC ApparatuS experiment, is one of the two large-scale experiments at the LHC.

Xu Qingzhou tapped his fingertips, thinking about solutions in his mind.

The middle-aged man put down his phone and reported to the old man drinking beside him: "Professor Baker, the people from the Xia Nation have all arrived."

Not to mention the bias in quotas—the Xia Nation's quota is pitifully small—even if they really joined the experiment, everyone comes from different countries, and they will compete openly and secretly, hoping to have more say in the experiment.

"Then I'll buy you a drink."

"Thank you."

Looking at his last disciple, Academician Yang shook his head helplessly and said: "If you are idle, tell Qingzhou about this experiment."

At the same time, in the room on the 8th floor.

"This has led to many things still being in the theoretical stage. Furthermore, it cannot be guaranteed that every theory is correct; experimental opportunities are limited, and trial-and-error costs are high."

Zhang Changqing continued to say: "Regarding the analysis plan for the diphoton channel, in addition to the Xia Nation team, the American team is also doing the same thing."

Through the introduction, Xu Qingzhou knew that this old man was Francesca Collins, the person in charge of the CMS laboratory and a world-class particle physicist.

The two shook hands with a smile.

"You, learn more from Qingzhou; don't think about going out to play all day." Before Xu Qingzhou could speak, Academician Yang had already spoken.

Seeing Xu Qingzhou's calm expression, Zhang Changqing felt that his description wasn't profound enough. He thought for a while and said: "This is like looking for a gold grain in a pile of sand; it's very difficult."

"Okay, let's go first." Academician Yang nodded. "Team Leader Yang." The middle-aged man shouted.

Common methods include optimizing photon screening conditions, such as energy thresholds, angle limits, isolation requirements, etc., to reduce the contribution of background events.

"We won't be worse than them." Academician Yang smiled.

Zhang Changqing let out a breath and said helplessly: "We are under a lot of pressure this time. Compared with the United States, the Xia Nation is indeed at a disadvantage in high-energy physics."

For example, the strong interaction of quarks and gluons can produce two high-energy photons; these photons might be mistaken for products of Higgs decay.

Speaking of this, Zhang Changqing shrugged and continued: "The LHC often breaks down, to the point that it needs long-term maintenance; it only restarted in March this year."

5 physicists, 2 mathematics experts.

Professor Collins smiled faintly, nodded to Xu Qingzhou and the others, turned, and left. Having been on a plane for a day, everyone was very tired, so they agreed to hold a meeting at 8:00 tomorrow and returned to their rooms.

Academician Yang praised Xu Qingzhou even more in his heart. It could be seen that this young man was sincere when he said those words—humble, eager to learn, steady, and hardworking; he was indeed material for scientific research.

Abby Baker talked to himself, his gaze falling on the last person, smiling, "Xu Qingzhou, a genius in mathematics. Unfortunately, this is physics, not mathematics."

"Okay."

"Hearing that you were coming, I even pushed back tonight's cocktail party."

Xu Qingzhou nodded slightly; he had long known these basic facts by heart.

At 12:00 local time, Xu Qingzhou closed his computer and went to bed. Perhaps because he was too tired, he fell into a deep sleep as soon as he touched the bed and didn't wake up until 7:00 the next morning.

He was actually quite surprised—when did the rigid and stubborn Xia Nation people become so adventurous, actually giving a quota to a young person?

And the first step currently is the analysis of the two decay channels: diphoton and 4-lepton.

After showering, seeing it wasn't 11:00 yet, Xu Qingzhou took out the draft paper he hadn't finished calculating on the plane during the day and continued to calculate.

"I was just saying." Zhang Changqing laughed sheepishly.

The group chatted and laughed as they entered the hotel to check in. Professor Collins still had things to do and had to leave first.

A middle-aged man with a refined face, wearing glasses, was looking down at materials; another was of similar age.

"Yes, it's my first time here." Xu Qingzhou looked out the window; this was indeed the first time in this life he had come here.

On the first day of their long-distance relationship, the school beauty Song sent a photo of herself and Er Miao, said good morning to Xu Qingzhou, and said she was going to the countryside to visit her grandparents.

For him, the Higgs boson stuff was not difficult to understand.

Xu Qingzhou smiled and reached out: "Very happy to meet you, Professor Collins."

Seeing Xu Qingzhou still nodding without that look of surprise, Zhang Changqing felt helpless and thought to himself: "Damn, is Xu Xu Shidi's mentality so strong? Or... does he have to wait until he truly comes into contact with the experiment to deeply realize it?"

Hearing this, Academician Yang put down the materials and said with a smile: "We don't need to be pessimistic. In recent years, the Xia Nation has still made many gratifying advances in this area, and some fields are even in a leading position."

"Because I feel that war is always there."

Or using multivariate analysis techniques to build a discriminator. This kind of discriminator can evaluate the possibility of an event being a signal or background based on multiple input variables—photon energy, momentum, angular distribution, etc... Zhang Changqing's gaze couldn't help but look at Xu Qingzhou. Xu Xu Shidi is daydreaming... is he not understanding? But thinking about it, it's normal. The teacher's rhythm is too fast, and Xu Xu Shidi is following the experimental group for the first time; it's normal not to keep up.

"The teacher is right, hehe, our Xia Nation is not weak now." Zhang Changqing said.

"It's okay."

"Task: Analysis of the diphoton channel."

Quantum mechanics describes the behavior and interactions of microscopic particles. The existence and characteristics of the Higgs boson were predicted and understood precisely on the basis of quantum mechanics, and its existence and properties also follow the laws of quantum field theory.

!.

There are 8 people in total.

"Let's go, junior brother."

Xu Qingzhou noticed something unusual, looked up, and saw Wang Qiming looking at him indifferently. He couldn't help but have a strange expression—does this person have a grudge against him? An hour passed, and Academician Yang waved his hand, signaling a break.

Abby Baker was noncommittal, his gaze looking through the window into the distance, and he said slowly: "An economist friend of mine said that there will be a 'war' between the Xia Nation and the United States in the future. I disagree."

Regarding diphotons, it is handled by the Xia Nation and the United States. As for 4-leptons, it is handled by Germany and India. Other member states will only be able to play a role later.

"Yang Bing, he and I are also old friends."

Mao Yi joked with a smile: "Young people's bodies are just good, unlike me, I couldn't sleep at all on the first day I came."

"Mr. Xu, welcome to the LHC."

"That's no problem."

"This must be Mr. Xu."

Xu Qingzhou nodded again; the CMS detector is located in Cessy, France.

Before leaving, Professor Collins reminded: "Yang, the American team is very powerful; you guys need to hurry up."

By nearly 8:00, Academician Yang and Wang Wang Shixiong Zhang had also arrived.

"Qingzhou, sit." Mao Yi looked up.

The middle-aged man is Shen Yuanjie, the deputy team leader of the Xia Nation team.

Zhang Changqing received a call on the side. After hanging up, he said: "Professor, the car is here."

Two figures were already waiting at the door—the middle-aged man with a Xia Nation face on the left, and a European old man on the right.

Zhang Changqing said enthusiastically: "Then when we have time, let's go for a stroll together. In this season, the scenery here in Switzerland is just right."

"Professor Mao, Professor Wang."

Zhang Changqing, like Gong Yunfei, is a chatterbox: "The members of the CMS Xia Nation team, besides professors from Jingda, also include experts from the Institute of High Energy Physics of the Academy of Sciences. Adding you, there are 8 people in total."

Without extra pleasantries, Academician Yang looked around and said: "Our team is participating in the CMS experiment for the second time. I'm too lazy to say pleasantries. We are pressed for time, so let's get straight to the topic."

"Junior brother, is this your first time in Switzerland?" Zhang Changqing asked with a smile.

Abby Baker picked up the materials on the side, which contained the participants of the Xia Nation team's CMS experiment.

"Actually, the experimental team originally only had 6 quotas, but because the LHC maintenance time was too long, not many results were produced, yet the membership fees were collected without missing a cent. So, every experiment was given two extra quotas."

"Among these extra quotas this time, one is Xiao Chen from the Academy of Sciences, and the other is you."

Zhang Changqing spread his hands: "Professor Wang Qiming originally wanted to let his own doctoral student come, but as a result..."

Xu Qingzhou suddenly realized; no wonder he looked at him with displeasure.

(End of chapter)