[ALICE3] PDG 0 stands for all pdgs

[njacazio]

No description provided.

[github-actions]

O2 linter results: ❌ 21 errors, ⚠️ 8 warnings, 🔕 0 disabled

[alibuild]

Auto-approving on behalf of @njacazio.

[alibuild]

Error while checking build/O2Physics/code-check for e72fde8 at 2026-07-15 17:35:

## sw/BUILD/O2Physics-latest/log
2026-07-15T17:30:11.365+0200 [23:139772862016064] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "ActionCache.GetActionResult()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]
2026-07-15T17:30:11.365+0200 [23:139772862016064] [executioncontext.cpp:544] [ERROR] Error while querying action cache at "http://localhost:8980": 14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused
2026-07-15T17:31:13.240+0200 [23:139772862016064] [buildboxcommon_grpcretrier.cpp:177] [ERROR] Retry limit (0) exceeded for "FindMissingBlobs()", last gRPC error was [14: failed to connect to all addresses; last error: UNKNOWN: ipv4:127.0.0.1:8980: Failed to connect to remote host: Connection refused]


## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 1 errors and 0 warnings.'
Found 1 errors and 0 warnings.
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/1a8c34e04b88e10a495394518a13feeaad01bf77/O2Physics-code-check/errors.txt
ALICE3/Tasks/alice3-qa-singleparticle.cxx:48:8: error: constructor does not initialize these fields: pdg [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 1 -gt 0 ]]
++ exit 1
--

Full log here.