2561 DPyC SMF false [["minutes", "Minutes"], ["notes", "Notes"], ["paper", "Paper"], ["poster", "Poster"], ["slides", "Slides"], ["summary", "Summary"]] Cinvestav ea481e58ca9c64e14d7982cb66bcd604 3312 The Division of Particles and Fields of the Mexican Physical Society (DPyC-SMF) organizes every year the Annual Meeting (RADPyC). This space is dedicated mainly for the exposure of results of graduate students and young researchers working in high energy physics and includes some review talks on the hot topics of the field. This year the meeting will be held in Auditorio José Ádem, Cinvestav, Mexico City, México. The scientific programme will consist of invited and contributed talks, and a poster session. It will begin in the morning of Wednesday 17 June and end before lunch on Friday 19 June. We will have the following invited talks: - Ana Colmenero, HAWC (UMSNH) - Jens Erler, The EW SM and constraints on NP (Mainz, PRISMA) - Iván Martínez Soler, Neutrino physics (Durham Univ.) - Cristina Oropeza, CMS (Ibero) - Antonio Ortiz, ALICE (ICN-UNAM) - Gabriel Palacios, Accelerator physics (UNAM) - Antonio Pich, Flavor physics (IFIC) - Pedro Podesta, Belle-II (UAS) - Selomit Ramírez, QCD, Loop Tree Duality, Quantum Computing (UAS) - Saúl Ramos, Flavor physics from a top-down perspective (IF-UNAM) - Alfredo Raya, NICA (UMSNH) - Eric Vázquez, DM-neutrinos (exp.) (IF-UNAM) The whole event can be followed by Zoom: https://us02web.zoom.us/j/85815121456?pwd=t1JWdqhgarEQRyewmXIEzNlkIcqU8a.1 (858 1512 1456 & 044752). Due to recent internet security problems at Cinvestav it will NOT be broadcasted via the DPyC facebook account (facebook is currently blocked on our premises). False 2026-06-17T09:00:00 2026-06-19T14:30:00 2026-03-23T09:50:55 2026-06-19T17:51:55 Mexico/General cinvestav f09241183e84638d226a8885656239cd Cinvestav 6be00aeecce15d4b2547496f45352003 CINVESTAV-IPN Mexico 207484e6583dd9c0c1af2f52ce04fdd8 Cinvestav ea481e58ca9c64e14d7982cb66bcd604 Cinvestav 3cd3ab69a079e614c15e4c750e7d3d60 BUAP 5848375cb8b0db28e94350f19dcb744f Benemérita Universidad Autónoma de Puebla 65efd11437264d48aa1f7486255a57bc 56 false [["minutes", "Minutes"], ["notes", "Notes"], ["paper", "Paper"], ["poster", "Poster"], ["slides", "Slides"], ["summary", "Summary"]] FCFM - BUAP c1c3089c3685d8d676c5409e01586224 FCFM - BUAP c1c3089c3685d8d676c5409e01586224 Benemerita Universidad Autonoma de Puebla 2b5d72d3f577b2043021a09e3d64539b Benemérita Universidad Autónoma de Puebla e5b8a62243e4c482657b5fe70ed80faa 00:15 In this work, we are interested in studying the spin-spinor formalism to deal with amplitudes for massive particles. After presenting the basic formulae and conventions, we evaluate the amplitudes for two specific examples, namely the decay $W \rightarrow l \nu_l$ and the reaction $ e^+ e^- \rightarrow \mu^+ \mu^-$. For each case, we display the amplitudes for all possible spin configurations for the initial and final states. We find it convenient to represent the flow of spin/helicities from the initial to the final particles in terms of graphs that resemble trees with branches. This simplifies the calculation of the total squared amplitude as the sum of the squares of the amplitudes for each branch; one can also verify the symmetries of the process by comparing different branches related by symmetries. Finally, we want to study the massless limit of the massive theory, and for this, we turn to the concept of Little Group Contraction (LGC), which was used by Inonu and Wigner to obtain the algebra of the Little Group (LG) for the massless case by taking the correct limit of the massive one.